MCQUAY WSHP PROBLEM

[mrushing]

I need some help. This is my first wshp ive worked on. the problem is the unit cuts on for about 30 seconds then shuts off like its tripping pressure switch. i checked the normal things high pressure switch, low pressure switch. i call tech support for help and according to them the board is indacating low temp switch which i bypassed. same problem still. installers did not leave manual for unit so i cant determine what the diagnostic code is on the board. yellow led flashing rapidly non stop. if anyone could help me i appreicate it. i need to have unit running in morning.model# is fcu060blfr

[william antley]

How's the water flow through the heat exchanger?

[VTP99]

I see one post has been deleted for DIY. Are you in the trade ?

[TAC Service]

Yellow flashing light on Mcquay WSHP is low temp. Is it tripping in heating or cooling ?

[mrushing]

its in cooling mode and yes ive been a tech for 3 years this is just my first wshp

[TMS134]

Check the sensor in the drain pan for high water/ clogged drain line. I had a similar problem and there isn't a fault code for it.

[ascj]

I'll assume your HP has a Mark IV board. The flashing yellow can be a open low temp switch or the E terminal is energized. Is there anything hooked up to the E terminal.....like a smoke detector, condensate pump switch, or etc?

And btw the code for a closed condensate pan switch is yellow on and green dim.

[BrianDarling]

Check the drain pan to make sure it is dry and the contact is dry also. This might be your problem.

[PhrankEspo]

Check the sensor in the drain pan for high water/ clogged drain line. I had a similar problem and there isn't a fault code for it.

The mcquay wshp's i've worked on indicate overflow if the yellow light is solid on the mark 4 board. I have however had a faulty low temp sensor and the light would not come on for low temp. Keep in mind, even if you bypass the temp sensor or pressure switch (TEMPORARILY of course), there is a time delay on the board, so keep it jumped. Also, the compressor overload may be open, this is NOT indicated on the board. Any time these units short cycle is usually due to low temp, high pressure, open O/L.

[newinthefield]

Check your loop temperature. If your supply water is to cold, system will trip on cold water safety. Also check tempersture sensor; but i doubt it is a sensor. There should be sticker on the side of control panel indicating all faulty codes. Also check on line. Dont give up easy. Good luck.

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[SanchezHVAC]

I need some help. This is my first wshp ive worked on. the problem is the unit cuts on for about 30 seconds then shuts off like its tripping pressure switch. i checked the normal things high pressure switch, low pressure switch. i call tech support for help and according to them the board is indacating low temp switch which i bypassed. same problem still. installers did not leave manual for unit so i cant determine what the diagnostic code is on the board. yellow led flashing rapidly non stop. if anyone could help me i appreicate it. i need to have unit running in morning.model# is fcu060blfr

Don't know if you remember what was causing the issue, but did you resolve it?

[VTP99]

It was 7 years ago I sure hope so.