No Blower

[trgardner]

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

[trgardner]

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

[Robert]

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

[trgardner]

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

[Robert]

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

[trgardner]

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

[Robert]

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

[trgardner]

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

[Robert]

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