mobilehomerepair.com

Hi,
I've been trying to get the blower running on an old intertherm FEH-020 electric furnace.

The condenser comes on when the t-stat calls for cool, but the blower doesn't. The blower will however work when the blower switch is in the "ON" position.
There is 24v at the t-stat, and the t-stat is working as it should, verified on another intertherm.
Any ideas would be helpful as i've ran out of things to check, hehe.
thanks,
Thomas

I almost forgot to mention i tested the fan relay and it is good.
I don't believe that it's getting 24v to it though when it calls for cool.
It was a situation where it had been working fine and just quit all of a sudden.

Thanks,
Thomas

Hi Thomas,


The same exact circuit which is used to energize blower in the cool-on setting is same one used in the cool-auto setting.


The only difference is at the t-stat itself.



Set t-stat to cool-auto-65*, then when condenser starts, but blower doesn't, test here:

Red/RC to a good ground for 24vac .

Yellow/Y to a good ground for 24vac.

Green/G to a good ground for 24vac.




Thanks,
Robert

Robert,

I wasn't clear in my previous post. The blower doesn't work from the t-stat on/auto switch, only at the "on/auto switch inside the furnace at the blower. I took a new piece of 18-5 t-stat wire and wired it up at the terminal block in the unit, had 24v red, yellow and green. T-stat 65* cool auto, condenser fires up, no blower. This unit also has a transformer in the condenser.
Thanks again for your help!!

Thomas

Test across fan relay 1 and 3 terminals for 24vac with t-stat set to cool-auto-65* .


Be sure you have 24vac from Green/G to ground at t-stat first and if so, test fan relay 1 and 3.


Thanks,
Robert

I went ahead and pulled the transformer out of the condensing unit, and wired everything up as if it was a single transformer unit and it works fine now.

thanks again for the help!!

Thomas

Hi Thomas,


Be sure the single transformer being used is sufficient VA rating to handle both the heat and a/c.


For single xfmr, I would go 40VA to be safe .


Thanks,
Robert

Yes sir, That's what i put in it, 40 VA.
You have to love the old Nordyne systems, I had the furnace wires stripped and rewired in about 10 minutes!!
I'm going to school for HVAC/R and the hands on portion of my final in Electronics/Electricity is wiring an electric furnace, so i should do pretty well on that part.

Thanks again,
Thomas

Hi Thomas,

You're very welcome, happy to help. Yep, electric furnaces are pretty straight forward.


The biggest obstacle in hvac for mobile homes that catch techs is when it is a 2 wire t-stat set up with a/c.


Best wishes with the rest of your schooling and a happy/successful career in hvac/r.


I turned 50 in June and August will be 30 years in hvac for me, so I'm on the downhill side of things now.


A great career and very rewarding if you study and accept that you will always be learning as it changes constantly from year to year.




Take care,
Robert