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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have a rheem furnace that short cycles and the code is

Customer Question

Customer: ***** *****, I have a rheem furnace that short cycles and the code is showing a1
JA: Thanks. Can you give me any more details about your issue?
Customer: the unit mod. # ***** ***** its a new unit
JA: OK got it. Last thing — JustAnswer charges a fee (generally around $18) to post your type of question to HVAC Experts (you only pay if satisfied). There are a couple customers ahead of you. Are you willing to wait a bit?
Customer: yes
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Submitted: 1 year ago.
Category: HVAC
Expert:  Phil replied 1 year ago.


Tell me please what the error code legend says about error code a1, and what the company that sold you the furnace has to say about the problem... that will save you and I a lot of time.

I need to know how short the cycles are, and where the thermostat is located in relation to the warm air supply registers (it may be in a warm air draft).

I need the brand and model number of the thermostat as well... it may be factory preset for a 0.5F differential, that will lead to short cycling in many cases.

We can go from there.

Customer: replied 1 year ago.
the error code is the #1 , and the legend does not have a #1, I by pass the thermostat and it still short cycle, the company that sold me the unit is close today. the brand name is ***** ***** the mod. # ***** *****
Expert:  Phil replied 1 year ago.


Next please attach a well focused, close up photo of the wiring diagram glued inside the service panel, the picture needs to be taken from straight on, in very good light.

You can use the paper clip- icon at the right end of the tool bar at the top of this dialog box to attach it here.,Include a picture of the thermostat wire connections to the printed circuit board in the same area.

If you have an error code showing, tell me what the code read out is on the wiring diagram or a sticker next to the diagram please.

If there is no paper clip-icon, look for the '+attachfiles'link at left of your send button.

I can mark it up with trouble shooting instructions.

We can go from there.

Customer: replied 1 year ago.
I will send you the photo Monday, Dec. 21, of the wire diagram and the wire connection to the board
Expert:  Phil replied 1 year ago.

Thanks, ***** ***** are exceedingly well focused I can mark them up with clear trouble shooting instructions, include what they have on the error codes too,

See you monday.