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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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Billy, my A/C unit cools well, but the unit outside keeps

Customer Question

Hi Billy, my A/C unit cools well, but the unit outside keeps going into what I think is the deicing mode: valve noise, then stops, than run for 10 seconds, then stops 3 seconds. This start/stop goes on for 5 reps and then the unit runs for 2 minutes before starting this patern again.
Submitted: 1 year ago.
Category: HVAC
Expert:  BillyHvac replied 1 year ago.
do you have make and model?
Is this an ac or a heat pump?
Customer: replied 1 year ago.
Payne model PH13NA030 -B, yes heat pump working all year long for cooling and heating.
Expert:  BillyHvac replied 1 year ago.
thank you.
this can be a few things...have you ever had a freon issue with more having to be added?
Customer: replied 1 year ago.
Yes, but the unit has been moved recently with all copper piping redone in shorter runs. I doubt it would be a slow leak, the problem started almost immediately. Also, there is no ice built-up in the unit inside the house and the air inside is very cool
Customer: replied 1 year ago.
Also the coil inside is only 1y old
Expert:  BillyHvac replied 1 year ago.
The reason I ask has to do with the too much freon.
It sounds like a cycling on high pressure....this could be restriction or too much freon.
Was same charge used?
Was nitrogen purged in pipe during rework?
Customer: replied 1 year ago.
I think so, but this is something i had noticed this before. The tech gave me a lecture on proper charge and purge when he completed his work... The unit is now closer so we hear it more . So you think the filter or line could be clogged? Any solution for that?
Expert:  BillyHvac replied 1 year ago.
If I knew the operating pressures I would know much more...when you charged unit what was head and suction?
Customer: replied 1 year ago.
? The tech did it. I think so as he used the instrument with 3 pressure reading between his tank and the unit. I fo not have the gear to check the pressure...
Expert:  BillyHvac replied 1 year ago.
was there a field service report stating things like pressure, superheat or subcooling?
was there no report?
Customer: replied 1 year ago.
No report
Expert:  BillyHvac replied 1 year ago.
I am stumped on this one. Without putting on some data loggers to see what is dropping and what pressures/temps.
However I am going to open this to the others here for a second opinion.
Customer: replied 1 year ago.
I am a home owner gathering intelligence to challenge what the next technician will tell me when he comes to my place. I had this unit fixed 3 times in the past 2 years... I don't have any of the instruments to gather the info you are looking for and the last guy did not leave any report. I will adk for one next time...
Customer: replied 1 year ago.
Can someone at least provide a list of potential causes/remedy in the order they would go at it on the assumption there is a high pressure on the system. thanks
Expert:  Phil replied 1 year ago.
Hello, That sort of erratic on-off behavior and need for repeated service points to electronics problems... those occur inside the systems printed circuit card, the chance of that in this case is over 90%.. there is a 10% chance there is another problem, such a loose wire connection. Tell me a lot about your technical skill set so that I can coach you most effectively. We can go from there.

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