Heating and air conditioning - Tech Tip II : TXV Basics

Author

Tech Tip II : TXV Basics

tony berlin

2006-03-16, 6:21 pm

How TXV's Improve SEER

TXVs that close when the compressor shuts off are referred to as
Hard Shut Off (HSO) TXVs.This isolates most of the charge in the
outdoor unit when the compressor is off, allowing evaporator pressure
to pull down faster on compressor start up.

TXV Problem Solving Basics

I. Underfeeding (Starving)-(Cooling Mode Only)
Symptoms: Frost on valve or indoor coil, low pressure indicated at
suction service valve, high superheat, low liquid pressure indicated
at LL service valve.
Possible Causes: Low refrigerant charge, no subcooling, clogged filter
drier, LL restriction, blocked TXV port, dead powerheard.

II. Overfeeding (Flooding)-(Cooling Mode Only)
Symptoms: High pressure at suction service valve, low superheat,
low or normal liquid pressue.
Possible Causes: Overcharged, TXV bulb not attached or improperly
attached to suction line, check valve blocked open, blocked external
equalizer, TXV stuck open.

III. Overfeeding (Flooding)-(Cooling Mode Only)
Symptoms: Low pressure at suction valve, low superheat, high or
normal pressure at LL valve.
Possible Causes: Blocked return air, dirty RA filter, dirty coil, blower
failure.

IV. Hunting (Cooling Mode Only)
Symptoms: Pressure at suction valve swings more than (+/-) 3 psi
(6 psi total), superheat or suction temp. swings more than (+/-) 4F
(8F total).
Possible Causes: Blocked RA, dirty RA filter, dirty coil, blower failure,
low refrigerant charge.

V. Restriction (Heating Mode Only)
Symptoms:High suction pressure, low LL pressure, unit runs for
brief period and trips on compressor O/L.
Possible Causes: Check valve stuck closed.

TXVs provide better performance over the entire operating range of
the system, protects the compressor from flood back, provides
better performance with low/high refrigerant charge conditions. TXVs
are also a crucial component in achieving 13 SEER + ratings.

---------------------------------
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PrecisionMechanicaL

2006-03-16, 8:21 pm

"tony berlin" <hvac_pro_series_moderator@yahoo.com> wrote in message
news:4419efce$0$20107$834e42db@reader.greatnowhere.com...
> How TXV's Improve SEER
>
> TXVs that close when the compressor shuts off are referred to as
> Hard Shut Off (HSO) TXVs.This isolates most of the charge in the
> outdoor unit when the compressor is off, allowing evaporator pressure
> to pull down faster on compressor start up.
>
> TXV Problem Solving Basics
>
> I. Underfeeding (Starving)-(Cooling Mode Only)
> Symptoms: Frost on valve or indoor coil, low pressure indicated at
> suction service valve, high superheat, low liquid pressure indicated
> at LL service valve.
> Possible Causes: Low refrigerant charge, no subcooling, clogged filter
> drier, LL restriction, blocked TXV port, dead powerheard.
>
> II. Overfeeding (Flooding)-(Cooling Mode Only)
> Symptoms: High pressure at suction service valve, low superheat,
> low or normal liquid pressue.
> Possible Causes: Overcharged, TXV bulb not attached or improperly
> attached to suction line, check valve blocked open, blocked external
> equalizer, TXV stuck open.
>
> III. Overfeeding (Flooding)-(Cooling Mode Only)
> Symptoms: Low pressure at suction valve, low superheat, high or
> normal pressure at LL valve.
> Possible Causes: Blocked return air, dirty RA filter, dirty coil, blower
> failure.
>
> IV. Hunting (Cooling Mode Only)
> Symptoms: Pressure at suction valve swings more than (+/-) 3 psi
> (6 psi total), superheat or suction temp. swings more than (+/-) 4F
> (8F total).
> Possible Causes: Blocked RA, dirty RA filter, dirty coil, blower
failure,
> low refrigerant charge.
>
> V. Restriction (Heating Mode Only)
> Symptoms:High suction pressure, low LL pressure, unit runs for
> brief period and trips on compressor O/L.
> Possible Causes: Check valve stuck closed.
>
> TXVs provide better performance over the entire operating range of
> the system, protects the compressor from flood back, provides
> better performance with low/high refrigerant charge conditions. TXVs
> are also a crucial component in achieving 13 SEER + ratings.
>
>

That's better, and thank you....

Excluding html formatting serves to make usenet posts compatable with
virtually all newsreaders and also simplifies maintaining intact the
attributes of earlier contributers where there are subsequent responders.

Next issue to address is that your software is apparently blocking replies
to both the unmoderated and unmoderated crosspost target...

--

SVL

HVACGod

2006-03-16, 8:21 pm

"PrecisionMechanicaL" <precisionmachinist@hotmail.com> wrote in message
news:09mdnXDBJNV0bITZnZ2dnUVZ_tOdnZ2d@scnresearch.com...
>
> "tony berlin" <hvac_pro_series_moderator@yahoo.com> wrote in message
> news:4419efce$0$20107$834e42db@reader.greatnowhere.com...
blower[color=darkred]
> failure,
>
>
> That's better, and thank you....
>
> Excluding html formatting serves to make usenet posts compatable with
> virtually all newsreaders and also simplifies maintaining intact the
> attributes of earlier contributers where there are subsequent responders.
>
> Next issue to address is that your software is apparently blocking replies
> to both the unmoderated and unmoderated crosspost target...
>
> --
>
> SVL
>
>
I will look at the software, did not think it was capable of blocking
anything, I will look at the established rules and correct them if that is
the problem. You can forward any posts directly to the submit address if
that is a problem you are experiencing, I wil look into it and correct it as
soon as possible, thanks for pointing it out.

PrecisionMechanicaL

2006-03-16, 10:21 pm

"HVACGod" <hvacprosubmit@HotPOP.com> wrote in message
news:441a0bcd$0$20105$834e42db@reader.greatnowhere.com...
replies[color=darkred]

( Correction ), had meant to say "both the moderated and unmoderated
crosspost target".....
[color=darkred]
>
> I will look at the software, did not think it was capable of blocking
> anything, I will look at the established rules and correct them if that is
>

Not exactly sure of what's going on here........just that yesterday evening
I found it necessary to submit a duplicate response ( the latter of which
was to alt.hvac alone ) as my first response ( where I had left both
crosspost targets left intact ) failed to propagate to either group. ( where
I'm thinking it logical to expect it should have gone to the unmoderated
group immediatly )

>
> the problem. You can forward any posts directly to the submit address if
> that is a problem you are experiencing, I wil look into it and correct it
as
> soon as possible, thanks for pointing it out.
>

Just that it seems kinda rude ( as well as utterly pointless ) to crosspost
at all ( if such is actually the case )......

So far as posting the "Tech tips"here....they likely are appreciated by at
least some folks, and so ( unless others strongly object ), do feel free to
continue in posting them--even suggest perhaps adding a "plug" in your sig
line, thus pointing those that might be interested towards the moderated
group.......if nothing else, the group does seem to have the potential of
becoming an uncluttered repository of technical information...whether or not
this is a 'good thing' depends much on one's own particular point of view.

Sorry, gotta run now........( this giving "useful feedback" to some
"net-nazi" is goina ruin my hard-earned "image" )

<wink>

Oh, and good luck with it.

--

SVL

2006-03-17, 9:21 am

PrecisionMechanicaL wrote:
> "HVACGod" <hvacprosubmit@HotPOP.com> wrote in message
> news:441a0bcd$0$20105$834e42db@reader.greatnowhere.com...
>
>
> replies
>
>
>
> ( Correction ), had meant to say "both the moderated and unmoderated
> crosspost target".....
>
>
>
>
> Not exactly sure of what's going on here........just that yesterday evening
> I found it necessary to submit a duplicate response ( the latter of which
> was to alt.hvac alone ) as my first response ( where I had left both
> crosspost targets left intact ) failed to propagate to either group. ( where
> I'm thinking it logical to expect it should have gone to the unmoderated
> group immediatly )
>
>
>
> as
>
>
>
> Just that it seems kinda rude ( as well as utterly pointless ) to crosspost
> at all ( if such is actually the case )......
>
> So far as posting the "Tech tips"here....they likely are appreciated by at
> least some folks, and so ( unless others strongly object ), do feel free to
> continue in posting them--even suggest perhaps adding a "plug" in your sig
> line, thus pointing those that might be interested towards the moderated
> group.......if nothing else, the group does seem to have the potential of
> becoming an uncluttered repository of technical information...whether or not
> this is a 'good thing' depends much on one's own particular point of view.
>
> Sorry, gotta run now........( this giving "useful feedback" to some
> "net-nazi" is goina ruin my hard-earned "image" )
>
> <wink>
>
> Oh, and good luck with it.

I could care less about the format that he posts with since I don't host
Google Groups, but I do wish he would post something that is technically
correct.

Richard Perry

Noon-Air

2006-03-17, 7:21 pm

"tony berlin" <hvac_pro_series_moderator@yahoo.com> wrote in message
news:4419efce$0$20107$834e42db@reader.greatnowhere.com...
How TXV's Improve SEER

TXVs that close when the compressor shuts off are referred to as
Hard Shut Off (HSO) TXVs.This isolates most of the charge in the
outdoor unit when the compressor is off, allowing evaporator pressure
to pull down faster on compressor start up.

TXV Problem Solving Basics

I. Underfeeding (Starving)-(Cooling Mode Only)
Symptoms: Frost on valve or indoor coil, low pressure indicated at
suction service valve, high sup normal liquid pressue.
Possible Causes: Overcharged, TXV bulb not attached or improperly
attached to suction line, check valve blocked open, blocked external
equalizer, TXV stuck open.

III. Overfeeding (Flooding)-(Cooling Mode Only)
Symptoms: Low pressure at suction valve, low superheat, high or
normal pressure at LL valve.
Possible Causes: Blocked return air, dirty RA filter, dirty coil, blower
failure.

IV. Hunting (Cooling Mode Only)
brief period and trips on compressor O/L.
Possible Causes: Check valve stuck closed.

TXVs provide better performance over the entire operating range of
the system, protects the compressor from flood back, provides
better performance with low/high refrigerant charge conditions. TXVs
are also a crucial component in achieving 13 SEER + ratings.

What if its a heat pump in heat mode??

PrecisionMechanicaL

2006-03-17, 11:21 pm

"RP" <no_mail_no_spam@yahoo.com> wrote in message
news:j96dnb7hduUbM4fZnZ2dnUVZ_tGdnZ2d@centurytel.net...

Has nothing to do with Google--( though googlers often cant seem to grasp
the whole concept......just that it fucks up the attributes, makes it all
appear as a single post.

===

Kinda like this, where your reply directly below is mixed in with mine,
making it appear as though it were me that actually wrote it.....

I could care less about the format that he posts with since I don't host
Google Groups, but I do wish he would post something that is technically
correct.

===

--Pretty soon you can't tell who in the fuck it was said that what.....and
gets esp bad if some XXXXXXX then top-posts....

Curious then, where exactly does the technical error lie ?

--

SVL

2006-03-18, 1:21 am

PrecisionMechanicaL wrote:
> "RP" <no_mail_no_spam@yahoo.com> wrote in message
> news:j96dnb7hduUbM4fZnZ2dnUVZ_tGdnZ2d@centurytel.net...
>
> Has nothing to do with Google--( though googlers often cant seem to grasp
> the whole concept......just that it fucks up the attributes, makes it all
> appear as a single post.
>
> ===
>
> Kinda like this, where your reply directly below is mixed in with mine,
> making it appear as though it were me that actually wrote it.....
>
> I could care less about the format that he posts with since I don't host
> Google Groups, but I do wish he would post something that is technically
> correct.
>
> ===
>
>
> --Pretty soon you can't tell who in the fuck it was said that what.....and
> gets esp bad if some XXXXXXX then top-posts....

Ok. I've never noticed that problem, but ok.

>
>
> Curious then, where exactly does the technical error lie ?

Let's review.

Earlier he Anthony posted:
[color=darkred]
to 0 to 5 VDC or 500 Ohm for 0 to 10 VDC.

My objection here is that he wasn't specific about which 4 to 20mA
device he was referring to, and even so, as it was written the sentence
is incorrect; mA cannot be converted to VDC, as this is a violation of
the known laws of physics. If one refers to a "device" as a "4 to 20mA
device", then it is assumed that we aren't speaking of devices in
general, but rather of a specific type of device, or more correctly a
very specific device of that type. It must also be assumed that only on
this particular "4 to 20mA" device can the voltage output or input be
modified with a resistor as described. OTOH we weren't instructed as to
the "usage" of the resistor, not even a hint as to how to "use" the
resistor, and thus the statement was meaningless, unless of course one
has extra sensory perception.
[color=darkred]
convert to VDC. A .pdf file on the module can be found here:[color=darkred]
the address below, it is a big file.[color=darkred]

Now for the second post.
[color=darkred]
[color=darkred]

Here we are left wondering "How is a faster pressure reduction in the
evaporator
more efficient?" One might even derive an argument to the contrary, to
wit, at higher suction pressures the volumetric efficiency is generally
improved. How does achieving a lower pressure faster provide increased
efficiency given the loss of volumetric efficiency that accompanies it?

There are answers to the questions, but "lower suction pressure faster"
isn't really one of them, that effect is just incidental, that is, it
does nothing to improve efficiency of itself. There is even a loss of
volumetric efficiency associated with lower suction pressure.
The benefits of the hard shut of TXV are
1) Liquid is suspended in the liquid line and inlet of TXV, which speeds
stabilization of the circuit after start up. The conditions for maximum
efficiency are reached sooner. Suction pressure stabilization is what
we're after, rather than the lower suction pressure.
[color=darkred]
[color=darkred]

I don't know what the above sentence says. I'll assume that it was
supposed to say "high superheat, normal liquid pressure.
If a TXV is underfeeding then superheat will be high, sure, but "head"
pressure will be low rather than normal at first, but then as the
compressor heats up the head pressure may actually be high. Point is,
head pressure is irrelevant to diagnosing an underfeeding TXV.
[color=darkred]

All of the above belong in the "overfeeding" section.

[color=darkred]

That should be "high pressure" at suction valve. In addition, head
pressure is irrelevant, but it will typically be low when this condition
occurs, depending upon to what degree the TXV is overfeeding. If the
overfeeding is excessive, then head pressure will be low, if it is
moderate head pressure may be actually a bit higher than normal.
[color=darkred]

None of these will cause overfeeding. A dirty coil will more often than
not cause underfeeding. Hunting is in turn the real cause of the
underfeeding condition.
[color=darkred]
[color=darkred]

Have no idea what he said here, but it sounds wrong.
[color=darkred]

I don't see the relevance, as the check valve should be closed in
cooling mode anyway. Hunting is caused by a capacity mismatch between
evaporator and TXV, namely when the TXV is too big. A dirty coil causes
a reduction in evaporator capacity, and a properly matched TXV is then
suddenly oversized. Hunting results. Installing an oversized TXV will of
course also cause it. Bulb location and mounting can also contribute, as
can equalizer tube location and condition. If the internal check valve
were stuck "open" to some degree then hunting might occur, but the stuck
closed thing, well frankly, I don't follow.
[color=darkred]

The rest is ok, but to be pedantic, achieving 13 SEER doesn't depend
upon TXV's in any way. TXV's aren't "crucial". They are however a
practical and sensible means to that end. They should've be installed on
most every HVAC system IMO, 13 SEER or no.

Richard Perry

PrecisionMechanicaL

2006-03-18, 2:21 am

"RP" <no_mail_no_spam@yahoo.com> wrote in message
news:wMadnQha4qvaCYbZnZ2dnUVZ_v2dnZ2d@centurytel.net...
>
> Let's review.
>
> Earlier he Anthony posted:
>
> to 0 to 5 VDC or 500 Ohm for 0 to 10 VDC.
>
> My objection here is that he wasn't specific about which 4 to 20mA
> device he was referring to, and even so, as it was written the sentence
> is incorrect; mA cannot be converted to VDC, as this is a violation of
> the known laws of physics. If one refers to a "device" as a "4 to 20mA
> device", then it is assumed that we aren't speaking of devices in
> general, but rather of a specific type of device, or more correctly a
> very specific device of that type. It must also be assumed that only on
> this particular "4 to 20mA" device can the voltage output or input be
> modified with a resistor as described. OTOH we weren't instructed as to
> the "usage" of the resistor, not even a hint as to how to "use" the
> resistor, and thus the statement was meaningless, unless of course one
> has extra sensory perception.
>
> convert to VDC. A .pdf file on the module can be found here:
> the address below, it is a big file.
>

Yeah, understood then....parallell resistance laws etc. I hadnt analyzed
that "tip" much if at all.

Gets really interesting when you "wheatstone bridge", for instance.

Still, mostly omissions, lack of clarification....

> Now for the second post.
>
>
>
> Here we are left wondering "How is a faster pressure reduction in the
> evaporator
> more efficient?" One might even derive an argument to the contrary, to
> wit, at higher suction pressures the volumetric efficiency is generally
> improved. How does achieving a lower pressure faster provide increased
> efficiency given the loss of volumetric efficiency that accompanies it?
>
> There are answers to the questions, but "lower suction pressure faster"
> isn't really one of them, that effect is just incidental, that is, it
> does nothing to improve efficiency of itself. There is even a loss of
> volumetric efficiency associated with lower suction pressure.
> The benefits of the hard shut of TXV are
> 1) Liquid is suspended in the liquid line and inlet of TXV, which speeds
> stabilization of the circuit after start up. The conditions for maximum
> efficiency are reached sooner. Suction pressure stabilization is what
> we're after, rather than the lower suction pressure.
>
>
>
> I don't know what the above sentence says. I'll assume that it was
> supposed to say "high superheat, normal liquid pressure.
> If a TXV is underfeeding then superheat will be high, sure, but "head"
> pressure will be low rather than normal at first, but then as the
> compressor heats up the head pressure may actually be high. Point is,
> head pressure is irrelevant to diagnosing an underfeeding TXV.
>
>
> All of the above belong in the "overfeeding" section.
>
>
>
> That should be "high pressure" at suction valve. In addition, head
> pressure is irrelevant, but it will typically be low when this condition
> occurs, depending upon to what degree the TXV is overfeeding. If the
> overfeeding is excessive, then head pressure will be low, if it is
> moderate head pressure may be actually a bit higher than normal.
>
blower[color=darkred]
>
> None of these will cause overfeeding. A dirty coil will more often than
> not cause underfeeding. Hunting is in turn the real cause of the
> underfeeding condition.
>
>
>
> Have no idea what he said here, but it sounds wrong.
>
>
> I don't see the relevance, as the check valve should be closed in
> cooling mode anyway. Hunting is caused by a capacity mismatch between
> evaporator and TXV, namely when the TXV is too big. A dirty coil causes
> a reduction in evaporator capacity, and a properly matched TXV is then
> suddenly oversized. Hunting results. Installing an oversized TXV will of
> course also cause it. Bulb location and mounting can also contribute, as
> can equalizer tube location and condition. If the internal check valve
> were stuck "open" to some degree then hunting might occur, but the stuck
> closed thing, well frankly, I don't follow.
>

Stuck, it'll act as fixed orifice...

>
>
>
> The rest is ok, but to be pedantic, achieving 13 SEER doesn't depend
> upon TXV's in any way. TXV's aren't "crucial". They are however a
> practical and sensible means to that end. They should've be installed on
> most every HVAC system IMO, 13 SEER or no.
>

Basically, sounds like he needs to first have his "tips" reviewed by others
then...before his simply splurting them out.

FWIW, I did find what appeared to be a pretty damned good explanation as to
txv operation some time ago on usenet ( not that I fully understand it all
at this point in time)

I'll leave it up to speculation which of us it was that had originally
authored it.

===

As you all know, I'm an absolute newbee at this shit......( so I'll get out
the vaseline in advance)

Given several heat pumps, supposedly r-22 was once in them...and I suspect
the gas had been pretty much removed from them all--yet pressure a reading
on equalized system consistantly shows appx 10 psi below what one would
expect according to the TP charts....appx 60 psi in 47 deg ambient.

ON compressor operation, these things go out almost immediadly on low
suction.

Dissolved gas retained in the oil is kinda making sense to me....but...why
is it low ???

Venting for appx 30 sec caused the pressure to drop all the way down to 20
psi, but next day was up to 60 again....

All my working units are reading 79 psi under same conditions....spot on
per the charts.

???

--

SVL

PrecisionMechanicaL

2006-03-18, 2:21 am

"PrecisionMechanicaL" <precisionmachinist@hotmail.com> wrote in message
news:I5SdnY-IUJ6QA4bZnZ2dnUVZ_s-dnZ2d@scnresearch.com...
>
> As you all know, I'm an absolute newbee at this shit......( so I'll get
out
> the vaseline in advance)
>
> Given several heat pumps, supposedly r-22 was once in them...and I suspect
> the gas had been pretty much removed from them all--yet pressure a reading
> on equalized system consistantly shows appx 10 psi below what one would
> expect according to the TP charts....appx 60 psi in 47 deg ambient.
>

Err correction--that's damned near to 20 psi difference........

>
> ON compressor operation, these things go out almost immediadly on low
> suction.
>
> Dissolved gas retained in the oil is kinda making sense to me....but...why
> is it low ???
>
> Venting for appx 30 sec caused the pressure to drop all the way down to 20
> psi, but next day was up to 60 again....
>
> All my working units are reading 79 psi under same conditions....spot on
> per the charts.
>
> ???
>

--

SVL

2006-03-18, 2:21 am

PrecisionMechanicaL wrote:

> "PrecisionMechanicaL" <precisionmachinist@hotmail.com> wrote in message
> news:I5SdnY-IUJ6QA4bZnZ2dnUVZ_s-dnZ2d@scnresearch.com...
>
>
> out
>
>
>
> Err correction--that's damned near to 20 psi difference........

That's typically a sign of oil flooding. The refrigerant/oil mixture
will not correspond to the refrigerant's TP chart.
Usually occurs immediately following a freeze-up condition.
[color=darkred]
>

That's in keeping with what I posted above. The cause of your iced up
evaporators.
[color=darkred]

Ever looked at the TP chart for refrigerant oil?
[color=darkred]

The conditions are probably not the same at all. You might check the air
flow and coil condition.

Richard Perry

PrecisionMechanicaL

2006-03-18, 3:21 am

"RP" <no_mail_no_spam@yahoo.com> wrote in message
news:q6qdnSCJJ4nDPIbZRVn-pg@centurytel.net...
>
>
> PrecisionMechanicaL wrote:
>
suspect[color=darkred]
reading[color=darkred]
>
> That's typically a sign of oil flooding. The refrigerant/oil mixture
> will not correspond to the refrigerant's TP chart.
> Usually occurs immediately following a freeze-up condition.
>

THinking theres not much else than oil in there...

>
> That's in keeping with what I posted above. The cause of your iced up
> evaporators.
>

Hard to tell as to icing--water source units, LP lockour occurs in either
mode....water mass flow in the coil making no noticable
differen....obvously, icing to the point of causing coil blockage in the
water coil isnt occuring in heating mode.....

Same low suction lockout behaviour occurs in either mode.

me....but...why[color=darkred]
>
> Ever looked at the TP chart for refrigerant oil?
>

Gotta link ?

--Much appreciated.....

20[color=darkred]
on[color=darkred]
>
> The conditions are probably not the same at all. You might check the air
> flow and coil condition.
>

All is clear, plenty of source mass flow on both the evap and condensor
sides......

Probly, just there's hardly any gas at all in them. ( IMO )

--

SVL

PrecisionMechanicaL

2006-03-18, 3:21 am

"PrecisionMechanicaL" <precisionmachinist@hotmail.com> wrote in message
news:wfKdnTw7JN--O4bZnZ2dnUVZ_vadnZ2d@scnresearch.com...
>
> "RP" <no_mail_no_spam@yahoo.com> wrote in message
> news:q6qdnSCJJ4nDPIbZRVn-pg@centurytel.net...
message[color=darkred]
get[color=darkred]
> suspect
> reading
would[color=darkred]
>
> THinking theres not much else than oil in there...
>
>
>
> Hard to tell as to icing--water source units, LP lockour occurs in either
> mode....water mass flow in the coil making no noticable
> differen....obvously, icing to the point of causing coil blockage in the
> water coil isnt occuring in heating mode.....
>
> Same low suction lockout behaviour occurs in either mode.
>
> me....but...why
>
> Gotta link ?
>
> --Much appreciated.....
>
>
to[color=darkred]
> 20
> on
>
>
> All is clear, plenty of source mass flow on both the evap and condensor
> sides......
>
> Probly, just there's hardly any gas at all in them. ( IMO )
>

These I bought, sight unseen...( I like to have spare heat pumps on
hand ).....Boeing Surplus...nameplate rating is for 58 oz of r-22--for water
source resi, pretty sure--but these compressor and fan are 460v 3 ph.

10 bucks a pop....so I dint do too bad, IMO.

God only knows whether or not they were actually using r-22 in em though.

And they coulda been running water or oil or nitrogen etc ( or who knows
what) into that water coil, for all I know...........

<G>

--

SVL

2006-03-18, 9:21 am

PrecisionMechanicaL wrote:
> "PrecisionMechanicaL" <precisionmachinist@hotmail.com> wrote in message
> news:wfKdnTw7JN--O4bZnZ2dnUVZ_vadnZ2d@scnresearch.com...
>
>
> message
>
>
> get
>
>
> would
>
>
> to
>
>
>
>
> These I bought, sight unseen...( I like to have spare heat pumps on
> hand ).....Boeing Surplus...nameplate rating is for 58 oz of r-22--for water
> source resi, pretty sure--but these compressor and fan are 460v 3 ph.
>
> 10 bucks a pop....so I dint do too bad, IMO.
>
> God only knows whether or not they were actually using r-22 in em though.
>
> And they coulda been running water or oil or nitrogen etc ( or who knows
> what) into that water coil, for all I know...........

LOL. You were holding out on the information. Ok, probably not freezing
up

Richard Perry

Walt

2006-03-18, 10:21 am

"DIDO" <jbravo@verizon.net> wrote in
news:avISf.4588$092.2746@trndny04:

>
> "tony berlin" <hvac_pro_series_moderator@yahoo.com> wrote in
> message
> news:4419efce$0$20107$834e42db@reader.greatnowhere.com...
> How TXV's Improve SEER
>
> TXVs that close when the compressor shuts off are referred
> to as Hard Shut Off (HSO) TXVs.This isolates most of the
> charge in the outdoor unit when the compressor is off,
> allowing evaporator pressure to pull down faster on
> compressor start up.
>
> I never hear of HSO and as I can say
> all refrigeration systems usualy have solenoid
> in liquid line that shuts off liquid on off cycle
> perventing floading on start up,
> however there are TXVs that closes as pressure
> goes up so call MOP rated valves but are
> never used in AC systems
>
> TXV Problem Solving Basics
>
> I. Underfeeding (Starving)-(Cooling Mode Only)
> Symptoms: Frost on valve or indoor coil,
> low pressure indicated at suction service valve,
> high sup normal liquid pressue.
>
> " you mean high superheat and most likly
> liqiud pressure willl be lower then normal"
>
> Possible Causes: Overcharged, TXV bulb not attached or
> improperly attached to suction line,
> check valve blocked open,
>
> "check valve closed"
> " ON SCROLL compressors only and if that
> happens it may blow through relif valve internaly
> onless it shut down on safety or OL"
>
> blocked external equalizer. "NOT LIKELY",
> TXV stuck open."SORRY NO NEVER"
> You mean closed bad power head (assambly)
> Did You forget humen error, filter cloged,
>
> III. Overfeeding (Flooding)-(Cooling Mode Only)
> Symptoms: Low pressure at suction valve,
> " sorry but I dont think so"
>
> low superheat, "WITH" high or normal pressure at LL valve.
> Possible Causes: Blocked return air, dirty RA filter,
> dirty coil, blower failure.
>
> IV. Hunting (Cooling Mode Only)
> brief period and trips on compressor O/L.
> Possible Causes: Check valve stuck closed.
> "Agian on scroll compressors only"
>
> TXVs provide better performance over the entire operating
> range of the system, protects the compressor from flood
> back, "Only if is sized properly and adjusted properly"
> provides better performance with low/high refrigerant charge
> conditions. TXVs are also a crucial component in achieving
> 13 SEER + ratings.
>
>
>
> ---------------------------------------------------------------
> ---------------
> Yahoo! Mail
> Use Photomail to share photos without annoying attachments.
> ------=_NextPart_000_0008_01C649F9.07608C10
> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
> <HTML><HEAD>
> <META http-equiv=Content-Type content="text/html;
> charset=iso-8859-1"> <META content="MSHTML 6.00.2900.2802"
> name=GENERATOR> <STYLE></STYLE>
> </HEAD>
> <BODY bgColor=#ffffff>
> <DIV><FONT face=Arial></FONT> </DIV>
> <BLOCKQUOTE dir=ltr
> style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT:
> 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
> <DIV>"tony berlin" <<A
> href="mailto:hvac_pro_series_moderator@yahoo.com">hvac_pro_se
> ries_moderator@yahoo.com</A>> wrote in message <A
> href="news:4419efce$0$20107$834e42db@reader.greatnowhere.com"
> .</DIV> <DIV>How TXV's Improve SEER</DIV>
> <DIV> </DIV>
> <DIV>TXVs that close when the compressor shuts off are
> referred to as </DIV> <DIV>Hard Shut Off (HSO) TXVs.This
> isolates most of the charge in the</DIV> <DIV>outdoor unit
> when the compressor is off, allowing evaporator
> pressure</DIV> <DIV>to pull down faster on compressor start
> up.</DIV> <DIV><FONT face=Arial></FONT> </DIV>
> <DIV><FONT face=Arial>I never hear of HSO and as I can
> say</FONT></DIV> <DIV><FONT face=Arial>all refrigeration
> systems usualy have solenoid</FONT></DIV>
> <DIV><FONT face=Arial>in liquid line that shuts off liquid
> on off cycle</FONT></DIV>
> <DIV><FONT face=Arial>perventing floading on start
> up,</FONT></DIV> <DIV><FONT face=Arial>however
> there are TXVs that closes as pressure</FONT></DIV>
> <DIV><FONT face=Arial>goes up so call MOP rated valves but
> are</FONT></DIV> <DIV><FONT face=Arial>never used in AC
> systems</FONT></DIV> <DIV><FONT
> face=Arial></FONT> </DIV> <DIV>TXV Problem Solving
> Basics</DIV> <DIV> </DIV>
> <DIV>I. Underfeeding (Starving)-(Cooling Mode Only)</DIV>
> <DIV>Symptoms: Frost on valve or indoor coil, </DIV>
> <DIV>low pressure indicated at suction service valve, </DIV>
> <DIV>high sup normal liquid pressue.</DIV>
> <DIV><FONT face=Arial></FONT> </DIV>
> <DIV>" you mean high superheat and most likly </DIV>
> <DIV>liqiud  pressure willl be lower then normal"</DIV>
> <DIV><FONT face=Arial></FONT> </DIV>
> <DIV>Possible Causes: Overcharged, TXV bulb not attached or
> improperly</DIV> <DIV>attached to suction line, </DIV>
> <DIV>check valve blocked open, </DIV>
> <DIV> </DIV>
> <DIV>"check valve closed"</DIV>
> <DIV>" ON SCROLL compressors only and if that </DIV>
> <DIV>happens it may blow through relif valve
> internaly</DIV> <DIV>onless it shut down on safety or
> OL"</DIV> <DIV><FONT face=Arial></FONT> </DIV>
> <DIV>blocked external equalizer.  "NOT LIKELY", </DIV>
> <DIV>TXV stuck open."SORRY NO NEVER"</DIV>
> <DIV>You mean closed bad power head (assambly)</DIV>
> <DIV><FONT face=Arial>Did You forget humen error,
> filter cloged,</FONT></DIV>
> <DIV><FONT face=Arial></FONT> </DIV>
> <DIV>III. Overfeeding (Flooding)-(Cooling Mode Only)</DIV>
> <DIV>Symptoms: Low pressure at suction valve, </DIV>
> <DIV>" sorry but I dont think so"</DIV>
> <DIV> </DIV>
> <DIV>low superheat, "WITH" high or normal pressure at LL
> valve.</DIV> <DIV>Possible Causes: Blocked return air, dirty
> RA filter, </DIV> <DIV>dirty coil, blower failure.</DIV>
> <DIV> </DIV>
> <DIV>IV. Hunting (Cooling Mode Only)</DIV>
> <DIV div for< runs unit pressure, LL low>
> <DIV>brief period and trips on compressor O/L.</DIV>
> <DIV>Possible Causes: Check valve stuck closed.</DIV>
> <DIV>"Agian on scroll compressors only"</DIV>
> <DIV> </DIV>
> <DIV>TXVs provide better performance over the entire
> operating range of </DIV> <DIV>the system, protects the
> compressor from flood back, </DIV> <DIV>"Only if is sized
> properly and adjusted properly"</DIV> <DIV>provides better
> performance with low/high refrigerant charge conditions.
> </DIV>
> <DIV>TXVs are also a crucial component in achieving 13 SEER
> + ratings.</DIV> <DIV> </DIV>
> <P>
> <HR SIZE=1>
> Yahoo! Mail<BR><A
> href="http://pa.yahoo.com/*http://us.rd.yahoo.com/evt=38867/*
> http://photomail.mail.yahoo.com">Use Photomail</A> to share
> photos without annoying
> attachments.</DIV></BLOCKQUOTE></BODY></HTML>
>
> ------=_NextPart_000_0008_01C649F9.07608C10--

What's with all the HTML????????????

Quit cross posting!

gofish@gonefishin.net

2006-03-18, 11:21 am

On Fri, 17 Mar 2006 21:42:25 -0800, "PrecisionMechanicaL"
<precisionmachinist@hotmail.com> wrote:

>
>"RP" <no_mail_no_spam@yahoo.com> wrote in message
>news:wMadnQha4qvaCYbZnZ2dnUVZ_v2dnZ2d@centurytel.net...
>
>Yeah, understood then....parallell resistance laws etc. I hadnt analyzed
>that "tip" much if at all.
>
>Gets really interesting when you "wheatstone bridge", for instance.
>
>Still, mostly omissions, lack of clarification....
>
>blower
>
>Stuck, it'll act as fixed orifice...
>
>
>Basically, sounds like he needs to first have his "tips" reviewed by others
>then...before his simply splurting them out.
>
>FWIW, I did find what appeared to be a pretty damned good explanation as to
>txv operation some time ago on usenet ( not that I fully understand it all
>at this point in time)
>
>I'll leave it up to speculation which of us it was that had originally
>authored it.
>
>
>===
>
>As you all know, I'm an absolute newbee at this shit......( so I'll get out
>the vaseline in advance)
>
>Given several heat pumps, supposedly r-22 was once in them...and I suspect
>the gas had been pretty much removed from them all--yet pressure a reading
>on equalized system consistantly shows appx 10 psi below what one would
>expect according to the TP charts....appx 60 psi in 47 deg ambient.
>
>ON compressor operation, these things go out almost immediadly on low
>suction.
>
>Dissolved gas retained in the oil is kinda making sense to me....but...why
>is it low ???
>
>Venting for appx 30 sec caused the pressure to drop all the way down to 20
>psi, but next day was up to 60 again....

Venting for 30 seconds? Say you wouldnt happen to have a
video of that would you? lol

>
>All my working units are reading 79 psi under same conditions....spot on
>per the charts.
>
>???

2006-03-18, 12:21 pm

gofish@gonefishin.net wrote:
> On Fri, 17 Mar 2006 21:42:25 -0800, "PrecisionMechanicaL"
> <precisionmachinist@hotmail.com> wrote:
>
>
>
>
>
>
> Venting for 30 seconds? Say you wouldnt happen to have a
> video of that would you? lol

Oh, was he talking about the SYSTEM??

Richard Perry

>
>

PrecisionMechanical

2006-03-18, 1:21 pm

Jake

2006-03-19, 12:21 am

> These I bought, sight unseen...( I like to have spare heat pumps on
> hand ).....Boeing Surplus...nameplate rating is for 58 oz of r-22--for water
> source resi, pretty sure--but these compressor and fan are 460v 3 ph.
>
> 10 bucks a pop....so I dint do too bad, IMO.
>
> God only knows whether or not they were actually using r-22 in em though.
>
> And they coulda been running water or oil or nitrogen etc ( or who knows
> what) into that water coil, for all I know...........
>
> <G>
>
> --
>
> SVL
>

Sam,

I really doubt nitrogen, given the symptoms you supplied. Oil, maybe...
like hydra oil.

As some others said, it appears a transfer problem. If you need water,
use a water/glycol solution 50/50 and see what happens.

If it's oil, you might need to slow down the GPM across the thing. VFD's
on centrifugal pumps are cheap enough.

Just my 2 cents... I didn't read the whole damn thread!

Jake

DIDO

2006-03-19, 11:21 am

If someone like use my user name
GOOD LUCK TO HER or HIM
I DON'T gave HECK
From Dido

"Walt" <walterme@privacy.net.invalid> wrote in message
news:441c12b5$0$15181$892e7fe2@authen.puce.readfreenews.net...
> "DIDO" <jbravo@verizon.net> wrote in
> news:avISf.4588$092.2746@trndny04:
>
>
>
> What's with all the HTML????????????
>
> Quit cross posting!

PrecisionMechanical

2006-03-23, 4:21 am

<gofish@gonefishin.net> wrote in message
news:8k5o12d1euhosvkc9ildl3qqfca0ctr97o@4ax.com...
> On Fri, 17 Mar 2006 21:42:25 -0800, "PrecisionMechanicaL"
> <precisionmachinist@hotmail.com> wrote:
>
pressure[color=darkred]
speeds[color=darkred]
external[color=darkred]
condition[color=darkred]
than[color=darkred]
causes[color=darkred]
of[color=darkred]
as[color=darkred]
stuck[color=darkred]
TXVs[color=darkred]
on[color=darkred]
others[color=darkred]
to[color=darkred]
all[color=darkred]
out[color=darkred]
suspect[color=darkred]
reading[color=darkred]
me....but...why[color=darkred]
20[color=darkred]
>
>
>
> Venting for 30 seconds? Say you wouldnt happen to have a
> video of that would you? lol
>

Was NO gas in them, except what was dissolved just as I had suspected ...had
my guy out today....pressure tested, then they all pulled 28 in vaccuum,
within a few minutes....alls good....factory charge replaced in em all and
they're operating normally.

( I'd list the actual pressures, temps etc...--excepting for the fact that'd
prolly bore most folks here to fucking tears)....

Exceptiopn bein only one of em that we werent paying atten to...got about an
5 oz extra--that's ones a hot fucking XXXXX, and probly gonna keep it
here--put it into the shop as recovery heating plant......where I can be
ASSsured it can be kept fed with a full water flow....

==

The darned shyster though ( else in-experienced )....I had six em heat pumps
all lined up for service...once we got done with the second one....I
mentioned " hell, ya got another gage set ???--if so...coluld we be pulling
a vacuum on this next unit while this one here is still busy getting
charged"

Yup....I'm for sure that he just fucking loves me by now <g>

We planning to drop loops into the creek that runs by his place sometime in
the near future.

Besides my paying him each time for his efforts, he learns something each
time--(as do I.)

--

SVL

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