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, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
Type Your HVAC Question Here...
Phil is online now
A new question is answered every 9 seconds

Rheem gf802 downflow 50kbtu- two stage short cycling like a

Customer Question

rheem gf802 downflow 50kbtu- two stage
short cycling like a bad flame sensor...problem is this a brand new furnace!
only thing wonky is, voltage to gas valve is all over the place- jumping from 7 to 90v and everything in between, on both stage pins
Submitted: 1 year ago.
Category: HVAC
Expert:  Tim H. replied 1 year ago.

Hi, I'm Tim and I'm an HVAC expert here to assist you with your questions. Please provide all information I request as it makes it more difficult to troubleshoot something when I'm not there onsite. Essentially, you become my eyes and ears. Thanks for the opportunity to help. At the end of our dialog, you will have a chance to rate my service, but please wait until we are finished and you're satisfied you have all the information you need.

Are you getting any LED flash code?

Expert:  Tim H. replied 1 year ago.

Also, please give me full model number off the tag inside the furnace.

Customer: replied 1 year ago.
Just tried responding via email but it treated it as a new question.Anyway, had an hvac guy out this am since I hadn't heard back from justanswer... they discovered the problem: the heat exchanger tubes had shifted forwards toward the burners/manifold, making contact with the flame sensor rod. After temporarily wedging the exchanger tubes back into place, he got it working, but will return Friday to remove the furnace and inspect the exchange box and mounts to see why things shifted. I attribute it to the idiot-monkeys that work for the trucking companies these days- the upper cabinet had a pretty big dent near the return air opening- was able to straighten it out, but there may have been some hidden damage not discovered until now...
Expert:  Tim H. replied 1 year ago.

OK, so issue resolved, then?

Customer: replied 1 year ago.
We'll see Friday- if exchanger can be secured in its proper place or if the furnace is scrap metal
Expert:  Tim H. replied 1 year ago.

OK, would you like me to close question, then?

Customer: replied 1 year ago.