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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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The diagnostic OC outdoor coil temp. gave me a F7 , the OA a

Customer Question

The diagnostic for the OC outdoor coil temp. gave me a F7 , the OA a F8, and the IH a F9 .This is a P-TAC unit. I can't find these failure codes in the service manual.Can you tell me what they are ?
Submitted: 1 year ago.
Category: HVAC
Expert:  Phil replied 1 year ago.

Hello, the error codes very useful... about 20% of the time.

about 50% of the time they are entirely bogus in one aspect or the other... especially those codes not found on the unit diagram or manuals.

We can discuss how that happens for a long time if you like. For now however there are much easier ways of sorting out whats wrong with your system, us old timer type technicians rely on those approaches....

for an exaggerated example if we see the blower motor smoking and notice that a wire terminal or two is discolored and the unit is around 7 years old.... we can say at first glance that the blower motor has burned out and be 99% accurate.

Let me know if you have a multi meter on hand and if you wish to send me a photo of the wiring diagram using the paper clip icon at the right end or your tool bar, or if would like me to opt out to other of our experts here.

We can go from there if you wish, in that case I need to know about how old the unit is, and if you have a multi meter or not.

Customer: replied 1 year ago.
I do have a multi meter.I do not see a paper clip icon . Model :PTCO73B25AM Serial:(###) ###-####MFG ;P1260817R I believe the year is 06. The blower runs well, tried a new board,wiring looks good ,old board looks good,so I put it back in .The coils are clean.I am maintenance in a retirement community, and my day ends soon so this may take till Monday
Expert:  Phil replied 1 year ago.

Hello again, have a good weekend I will see you monday

Photos of the wiring diagram need to be taken close up, from straight on, and very well lit and exceedingly well focused.

Click here

Customer: replied 1 year ago. Here is a link to the wiring diagram
Expert:  Phil replied 1 year ago.

Thanks, ***** ***** link is to your email and does not open on this end..... the model number is ***** bringing anything up on google either.

I will opt out so other of our experts here can see your question.