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HVAC Guru
HVAC Guru, HVAC TECH
Category: HVAC
Satisfied Customers: 14472
Experience:  15yrs in the HVAC industry with certificates and degrees.
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McQuay Chiller AWS350 repeatedly alarms every 20 min on both

Customer Question

McQuay Chiller AWS350
repeatedly alarms every 20 min on both circuits
Condenser press sensor
Suction Temp sensor
Evap press low. ( Sight glasses full. Sub cooling 8-11 deg )
Submitted: 11 months ago.
Category: HVAC
Expert:  HVAC Guru replied 11 months ago.

Hello and thanks for using this service, if you have been waiting do not worry or get upset. I am HVAC Guru an extremely experienced tech on the site and I try to get to as many customers as I can. I just picked up your question now. NOTE it takes time for me to type research and add links so please wait for me to respond back I can only do this so fast. Secondly I am not paid anything until you rate my service good using the STAR RATING LINK at the top of your page, the money is paid to the site not me directly.

What are the system pressures?

Customer: replied 11 months ago.
R134a. 140 hi and 38 lo
Expert:  HVAC Guru replied 11 months ago.

SOunds like the pressures are good, since both are doing it the board may be bad, have you checked the sensors?

Customer: replied 11 months ago.
Are ya there Guru ?
Expert:  HVAC Guru replied 11 months ago.

Yes did you get my message?

Customer: replied 11 months ago.
You asked for system pressures, I responded 140 and 38 on r 134. Is there another question ?
Expert:  HVAC Guru replied 11 months ago.

SOunds like the pressures are good, since both are doing it the board may be bad, have you checked the sensors?

Customer: replied 11 months ago.
Do you know what the sensor resistances are ? I have no specs. For them and it appears the IP board on both machines have been replaced before as each machine has one laying in it !
Expert:  HVAC Guru replied 11 months ago.

See if the read shorted or open with your ohm meter unplugged when it trips off....I doubt they are both bad at all..sounds more like a bad control.