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Phil, Mechanical Engineer
Category: HVAC
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Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have a Goodman electric furnace consisting of an air exchanger

Customer Question

I have a Goodman electric furnace consisting of an air exchanger with electric elements an a heatpump/AC outside. My problem is the heating element and fan will not shut off. I can pull the tstat off the wall and it continues to run. The only way to shut it off is with the breaker. I have changed the tstat,sequencer and fan relay.???
Submitted: 1 year ago.
Category: HVAC
Expert:  gotoman for ac replied 1 year ago.
Russ here. Welcome. I am here to help. Please do not rate until you are satisfied with answer. Always available for follow up questions.Can you give me model number of air handler please. Russ
Customer: replied 1 year ago.

Goodman ARPF182416BA

Expert:  gotoman for ac replied 1 year ago.
One moment while I pull wiring diagram
Expert:  gotoman for ac replied 1 year ago.
Check your fan board and see if all wires are in correct place. Purple should go N/C. Red from transformer to N/O and leas from fan to common. Russ
Customer: replied 1 year ago.

will do

Expert:  gotoman for ac replied 1 year ago.
I will be here. russ
Customer: replied 1 year ago.

Wires are as you indicated.

Expert:  gotoman for ac replied 1 year ago.
If you remove purple wire off N/C does fan stop. Russ
Customer: replied 1 year ago.

Fan runs just fine with the wire removed.

Expert:  gotoman for ac replied 1 year ago.
That wire comes from sequencer and is only suppose to supply power to fan motor when calling for heat. . Tracing that wire back is that the sequencer you replaced. Russ
Customer: replied 1 year ago.

Yes sir that is the one.

Expert:  gotoman for ac replied 1 year ago.
You traced wire back. Remove wire on opposite side of sequencer and see if the fan stops running. Russ
Customer: replied 1 year ago.

If you are referring to the 8 or 10 gauge wire that leads to the breaker then yes the fan still runs with this wire removed from the sequencer.

Expert:  gotoman for ac replied 1 year ago.
Getting close. Should have black wire going to elements and a purple wire. Remove purple wire and see if fan stops. Russ
Customer: replied 1 year ago.

Ok, the purple wire from the sequencer is the other end of the purple wire we unplugged at the board. Am I supposed to have more than one wire unplugged at this point? I've been plugging wires back in after each test.

Expert:  gotoman for ac replied 1 year ago.
You are doing things correct. The purple wire on sequencer is the one I need you to remove. Russ
Expert:  gotoman for ac replied 1 year ago.
Be offline for about 30 minutes but will get back with you. Have wiring diagram in front of me. Russ
Customer: replied 1 year ago.

Alright, the fan still runs with the purple removed from the sequencer.

Customer: replied 1 year ago.

Ok it's been well over an hour and I need to get off of here for dinner. I'd like to take this up tomorrow but not sure how. Please let me know.

Expert:  gotoman for ac replied 1 year ago.
Very sorry. Darn server crashed and just now back online. You removed purple wire on the sequencer. That wire feeds power to fan when calling for heat. Make sure everything on thermostat is on position. When you removed purple wire from the fan board everything ran normal correct fan shut off and would come on when thermostat fan position turned to on. Russ
Customer: replied 1 year ago.

Maybe go back and reread the original post and what we have done so far. System is in auto and fan is in auto. House is 66 and the heat setpoint is 62. Heatpump is switched off at the breaker. If I energize the furnace with the breaker the heat strip and the fan come on even if it is 80 in the house. We have disconnected the purple wire from first the board and then the sequencer which was essentially the same test and the fan still runs. I have assumed from the beginning that the fan comes on because the heat strip comes on. I can shut the system off at the tstat and it continues to run or even remove the tstat from its backing plate so all I have is wires hooked to their terminals and it continues to run. A voltage test to these terminals while the fan is running shows 27.4 volts to R & the jumpered Rc. .475 to the G or fan terminal and 0 volts to all other terminals. Reminder; The tstat, sequencer and fan relay are all new having been changed out one at a time.

Expert:  gotoman for ac replied 1 year ago.
There is a white wire going to outside unit. Disconnect wire and see if the fan stops and heat drops out. Russ
Customer: replied 1 year ago.

The only white wire comes from the sequencer and is wire nutted to the white and black wires from the tstat and a blck 24 vac wire going to the heat pump. The white 24 vac wire in the harness going to the heat pump is not connected at either end. And as a side note; this issue occurs with the heat pump on or off at the breaker box.

Expert:  gotoman for ac replied 1 year ago.
Do you have a voltmeter.
Customer: replied 1 year ago.

Yes

Expert:  gotoman for ac replied 1 year ago.
Test across top of sequencer and see what voltage reading you get. Russ
Customer: replied 1 year ago.

Across the top I'm getting 1.75 V and across the next terminal down (red wires going to element) I'm getting 245 V.

I checked at the heat pump and the black 24 vac wire is wire nutted to a bigger white wire just like in the furnace.

Expert:  gotoman for ac replied 1 year ago.
Check across bottom 24 volt terminals. Russ
Expert:  gotoman for ac replied 1 year ago.
I know you changed sequencer but you have no voltage across top contacts and 220 across bottom. Means bad sequencer. Russ
Customer: replied 1 year ago.

1.75 across top

245 across middle

Zero across bottom

Unhooked black 24 vac wire that is going to the white heat pump wire and both heat and fan are still running.

Expert:  gotoman for ac replied 1 year ago.
No voltage across top means contacts are closed. Bad sequencer. Russ
Customer: replied 1 year ago.

It's going to take me 2 to 3 days to get another sequencer here. May I contact you after I get it installed? And thanks for your help.

Expert:  gotoman for ac replied 1 year ago.
Yes you can we can keep it open. Russ
Customer: replied 1 year ago.

Thank you

Expert:  gotoman for ac replied 1 year ago.
I will be here. Russ