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Home > Archive > Heating and air conditioning > May 2006 > Recommended Safeties on Commercial Condensers?
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Recommended Safeties on Commercial Condensers?
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| So... we're doing a energy controls package on a decent sized office
building.
Control system has been installed for 4 months and working fine.
Controls were retrofitted to early 90's Carrier Commercial RTU's in the
10 ton range.
The controls manage heat/cool calls throughout the building, handling
zoning, have numerous alarm functions.
I got a call this afternoon that a DA sensor was reading out of
tolerance. Air leaving the EVAP was hotter than when it entered.
Went out there and the Evap. liquid line was too hot to touch. Suction
line was lukewarm.
Since it's a cap-tube, I immediately worried about a orifice problem,
but wanted to take a close look.
The condenser fan was tripped on internal temperature. Appears it's the
Carrier original OEM motor and blade.
The compressor never stopped. NO HP limit, no current sense, no nothing
to prevent this problem.
Do I need to add additional safeties here?
Jake
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| Harry Cox 2006-05-27, 12:21 am |
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<.p.jm@see_my_sig_for_address.com> wrote in message
news:qqaf725or3ust0cfltlk5g5mfhqfm8toof@4ax.com...
> On Fri, 26 May 2006 21:26:00 -0400, Jake <jkelleyus@insightbb.com>
> wrote:
>
>
> Wouldn't hurt to put HP lockouts on evey circuit, preferably
> with indicators to your BMS also.
>
And also place the identical on the low side up to the actual lockout--only
reason for keeping them separate instead of just putting both sensor in
series being for the purpose of data logging...
--
SVL
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| Murdentech 2006-05-27, 11:21 am |
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"Jake" <jkelleyus@insightbb.com> wrote in message
news:qridnalxe5I1N-rZRVn-sg@insightbb.com...
>
> I got a call this afternoon that a DA sensor was reading out of tolerance.
> Air leaving the EVAP was hotter than when it entered.
>
> Went out there and the Evap. liquid line was too hot to touch. Suction
> line was lukewarm.
>
> The condenser fan was tripped on internal temperature. Appears it's the
> Carrier original OEM motor and blade.
>
> The compressor never stopped. NO HP limit, no current sense, no nothing to
> prevent this problem.
>
> Do I need to add additional safeties here?
>
> Jake
I like to see dual pressure safeties on all refrigerant circuits. Since you
have a control system that should be able to log problems and send alarms,
you do not necessarily need lock-out safeties. However, depending on the
system and other parameters, lock-out safeties can prevent masking of
problems which can lead to further equipment damage.
Individual HP and LP switches are fine as well. They should be wired to drop
out just the respective compressor contactor, not the primary control
circuit.
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| dwef@ccc.com 2006-05-27, 1:21 pm |
| On Sat, 27 May 2006 01:30:29 GMT, .p.jm@see_my_sig_for_address.com
wrote:
Bite me XXXXX Punk[color=darkred]
>
> Wouldn't hurt to put HP lockouts on evey circuit, preferably
>with indicators to your BMS also.
>
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