A few questions regarding electric furnace

[cyay918]

The furnace in question is a Nordyne E2EH 015HA.

Ill try to sum this up in a nutshell.


Last summer, my mother did not have AC in her trailer, she called a friend who knew a little about HVAC and determined that the AC was running but the heater coils were also kicking on. So it was heating the cool air that was being blown canceling each other out.

I dont know what all he tested or checked, but his solution at the time was to disconnect the heating elements by disconnecting the black wires from each one.

I have opened this panel and I am familiar with some of the components since I build large HVAC control boxes for Carrier.

It is switching over to winter, and she has no heat with those disconnected. When plugging them back up, the same thing happens. Even when the thermostat is set for cool, and turned all the way down, the coils still come on and attempt to heat the cold air.

The heating part works fine. Heat comes out of the vents, and the outside unit doesn't turn on so I know the AC is at least cutting off when the heat is running.

Ive also noticed that the heating elements remain on even when the fan isn't blowing. I dont think they are on constantly since I can hear ticking every now and again from the relay but what little knowledge I do have cant come up with a reason the coils would come on, without the fan blowing when the temp in the room is already at what the thermostat is set for. Is this normal?


Thank you all for your advice. She is not without heat or air right now but it has to be one or the other. Either I connect the wires and she has heat with no AC, or I disconnect the wires to disable the heating coils to give her AC.


The relay and sequencer assembly is H1-110 C1-110 and I know they are easily found on the internet. Could this part be the cause of the trouble? I cant think of anythign else it could be aside from like a control board somewhere. The transformer, breakers, and all the wires look to be in great condition.

If you need any more info from me, let me know and ill do what I can. I just wanted to get help here before I call and have a service tech charge my mother out the wazoo.

[Robert]

IF you do not have a call for heat from t-stat while a/c is running, most likely a bad sequencer.


Sequencer # 01-0842 can be seen and ordered from here by paging down:

http://www.aberdeenhomerepair.com/store ... 8621678%29


Thanks,
Robert

[cyay918]

Thanks robert. The t-stat does call for heat and it works fine. Again, the issue is that the heating elements inside the furnace stay on regardless if the t-stat is set for heat or cool. The elements are on even when the fan isnt blowing which is why im suspecting a bad relay / sequencer. Something is stuck somewhere to cause that I would imagine.

[Robert]

You're misunderstanding what I'm saying. When you have t-stat set for cooling and a/c is running, need to know IF the t-stat at that same time is also calling for heat.


Could be bad t-stat, shorted wires, bad sequencer or an element has broke or fallen down touching furnace frame.


How many wires are connected to your t-stat ?


You can turn furnace power off and allow it to cool. Then remove blower assembly and look down on elements to see if any appear broken or have fallen and touching sides .


Thanks,
Robert

[cyay918]

Ah I see what you are saying. I took the tstat off the wall today. It is a honeywell RTH2310. There are 8 wires coming from the wall, only 5 are being used and according to the manual, they are all in the right places

Red - RH
Jumper from RH to RC
White - W
Green - G
Yellow - Y


There is an orange, blue, and brown wire coming from the wall but they arent being used and there isn't anywhere to put them on the thermostat.

How do I check for the situation you are speaking of? If I disconnect the white wire from the tstat, then turn the AC on, will that tell me if the tstat is bad? From what I read, the white wire is the one that calls for the heat so if it is disconnected, but the elements still come on...then its not the tstat right? I can check that if you think that would be the next step.

[Robert]

Yes, disconnect the white wire, set t-stat to cool-auto, turn on a/c and see if elements still come on.




Thanks,
Robert

[cyay918]

Ok I took the white wire off and tested. I couldn't really tell much difference. The coils still seem to be coming on with or without the white wire. To verify this, I left the white wire off and the element still felt warm. I checked the temp of the air with the coils disconnected from power and the temp out of the vents was cool. When I plugged the elements back up, the air coming out of the vents was 10 degrees higher.

The elements are still heating regardless if the white wire is connected or not. Also, I tried another thermostat with the same results. We had the original non-programmable one still put up in the closet.

To complicate things even more, the elements stay on regardless if the blower is on or not which could be a potential fire risk?

If its not the thermostat, and its not the elements, the only thing left is the relay/sequencer unless you can think of something else to check.

I really appreciate all your help in this matter.

[cyay918]

Ive ordered a relay / sequencer for the furnace that matches the model and everything of the one that is in there now.

I will let you know if that fixes the problem. Thanks again for your help!

[Robert]

Sequencer is most likely problem by what you stated. Correct sequencer is # 01-0842.


It can be seen here by paging down:

http://www.mobilehomerepair.com/Order4b.html




Thanks,
Robert

[cyay918]

Robert,

The sequencer came in today. I installed it according to where the wires were on the old one. The lay out was a little different than the original but it fixed all the problems!

The air works without the heating elements coming on.

The heat works and the elements turn off when the blower stops too!


Thank you for all your help, you saved me a chunk of change by calling a professional. I really appreciate it!

[Robert]

You're very welcome, happy to help.




Thanks,
Robert