Heating, Air Conditioning, Fridge, HVAC/Electric Furnace

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QUESTION: Hello Jim,

I'm helping a friend with a furnace problem.
He has a heat pump outside, and a electric furnace for colder temps when heat pump is off. I've checked elements, limit switches, connections, fan runs but no heat from elements (3).  I noticed some water had dripped from the above evaporator over the summer and has rusted a couple of diodes  in the circuit board at the bottom.  Other than that, I'm stumped! Maybe a relay? how do you test for that?

ANSWER: Hello Dustin, I can better help you if you can get me the Make and model # on the furnace. I have serviced hundreds of electric furnaces so I can give some general info:

The elements will come when the temp in the house is 2* below the thermostat setting, when the heat pump goes into defrost mode, or when the heat pump runs for say 15 minute. If the stat has a emergency switch, have him switch it and see if the elements come on.

Let me know. JIM

---------- FOLLOW-UP ----------

QUESTION: Jim,
York Model # AHP60D3XH21B
       Serial  #ADK8243969
Furnace Model # THGD60S21S1A
         Serial #  WDK8345759

We tried both settings on the thermostat. No change

Thanks again for your help on this

Dustin

Answer
Hi Dustin, I found the wiring diagram for the furnace. There are 2 sequencers ( relays ) that bring the heating elements on.  With the stat calling for electric heat, you need to check the voltage from the stat. There is a terminal strip in the furnace. Put you meter on # 4 and #5 you should have 24v. Then test #4 and #6. This will tell you if the stat is working correctly

Also there are 3 fusible links one for each element. It's not likely all three have opened but it worth checking out.

Let me know what you find. JIM  

Heating, Air Conditioning, Fridge, HVAC

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Jim S.

Expertise

I can answer questions on gas or electric furnaces, ac units and heat pumps. I don't work on boilers,chillers,or home appliances.

Experience

I have been in the HVAC trade for over 35 years. For the past 15 years I have owned my own business. I am semi-retired so I can answer questions in a timely manner.

Education/Credentials
I attended trade school for 5 years on weekends and evenings. This was very hard to do, but well worth it!

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