How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Phil Your Own Question
Phil
Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
23932409
Type Your HVAC Question Here...
Phil is online now
A new question is answered every 9 seconds

I need help troubleshooting Rheem RAHE-036JAS, Armstrong G1N80AU125D20C-1,

Customer Question

I need help troubleshooting Rheem RAHE-036JAS, Armstrong G1N80AU125D20C-1, Honeywell ST9160B 1068 Board, Honeywell SV9520H 8034 Gas Valve.
Submitted: 1 year ago.
Category: HVAC
Expert:  Phil replied 1 year ago.
Welcome! Your question will be answered in detail. UP to 48 hours step by step coaching on diagnosis & repairs $38 additional.
We can begin by doing a heat stress test on the printed circuit board (the one the thermostat wires are connected to... indication so far indicate a stuck fan relay or defective connection inside the board that is keeping the fan relay operating.
Stress test the printed circuit card.
Use a hair drier to slowly and gently warm the card to 120F (warm to the touch but not hot and not over 140F)... if you get any change in behavior that means the card is bad...
A micro crack has opened in the printed circuit at a solder joint, or inside its CPU in that case .... or a short circuit has developed as the card expanded when you heated it.
Constant expansion and contraction as these electronics heat and during their duty cycles over the years is what wears these cards out.
It is also a good idea to replug all of the connections in the unit, that burnishes any oxidized terminal connections and will sometimes solve the problem, especially at the printed circuit card and in any sensor molex connectors. Do that with the power off to the unit of course.
These cards are also damaged by Electrical Spikes caused by power failures and lightning. These high voltage spikes can literally explode the fine 'wire' connections inside the chip. There is also a shunt type device, often printed on to the card that allows a high voltage spike to arc across to ground harmlessly, some of these can wear out after a few times and allow the high voltage spike into the rest of the card and the CPU micro-circuits. The high end printed circuit cards use a large capacitor like device, or several in parallel, to capture and release such surges, these do not wear out.
If that fails use the 'attach files' link at the bottom left of your reply box to attach a picture of the thermostat wire connections there, I can use that to coach you on a few tests.
.