EB17A A/C works fine but no heat.

xsubdude99 · Sun Oct 03, 2010 8:16 am

I have an EB17A, which is the one with the 901698 relay box. The fan works fine, the A/C works fine, but when I select heat neither the fan or the heater come on. Any ideas? Maybe a relay box problem or even a sequencer, if this unit even has one.

Robert · Mon Oct 04, 2010 12:17 am

Would need to see if the sequencer is getting the low voltage signal from t-stat.

Could be the sequencer, t-stat, loose wire, etc...

Thanks,
Robert

xsubdude99 · Mon Oct 04, 2010 6:27 am

I can check all that but I'm not sure where the sequencer is located. Also, if I want to check the t-stat, since its a two wire unit can't I just short out the wires to see if it kicks on the heater?

I went ahead and jumped out the two wires coming from the t-stat and I can hear the relay # 621099 clicking, and I am getting the 24 volts at that relay, which I think is the sequencer but nothing happens.

Robert · Tue Oct 05, 2010 12:11 am

Hi,

621099 is a relay control. Sequencer is mounted on back wall just over/above the heating elements with transformer and fan relay.

The very bottom terminals are the 24vac, middle and top are contacts for the elements.

Thanks,
Robert

xsubdude99 · Tue Oct 12, 2010 3:12 pm

I still haven't been able to find this sequencer. The only thing I have on this EB17A is 901698 relay box and from there the wiring harness goes to the fan and to the heater elements via a small tranformer. I have taken out the heating elements just to make sure the sequencer wasn't in the vent shaft itself but all I see is the inside on the fan. I have also looked behind the fan assembly and nothing is back there either. Any ideas?

Robert · Wed Oct 13, 2010 12:43 pm

It is mounted just above the heating elements on furnace facing.

To the right is the breakers. To the left is the fan relay and transformer.

Thanks,
Robert

xsubdude99 · Thu Oct 14, 2010 7:08 pm

I think I was looking for some type of circuit card or something. I finally figured out that circuit and I'm only getting about 8 volts from that 24 volt transformer. On its label it shows a part number of 6214140 do you all carry one of those or one that'll work?

Robert · Thu Oct 14, 2010 9:14 pm

How many volts are you reading on the LINE/240vac side ?

Thanks,
Robert

xsubdude99 · Thu Oct 14, 2010 9:35 pm

when I go across the terminals I read 240

Robert · Thu Oct 14, 2010 11:06 pm

Hi,

I just reread your replies. IF your a/c is working, then your transformer is fine . You would not have a/c without the needed 24vac from transformer.

Transformer # 025-18452-700 can be seen and ordered from here by paging down:

http://www.aberdeenhomerepair.com/store ... esults.php

I would test meter and retest transformer though or see if a/c works now.

IF a/c works, transformer is working also.

Thanks,
Robert

xsubdude99 · Fri Oct 15, 2010 8:14 am

I checked again. That transformer has an input of 248 and no output, but I don't think it really has anything to do with the A/C. I completely disconnected the input to the transformer and the A/C still came on. I'm going to go ahead and order that transformer. Thanks for all your help on this.

Robert · Fri Oct 15, 2010 11:37 pm

Hi,

Your heat and a/c both require 24vac low voltage to work. Unless there is another transformer, then that transformer would have to be ok for the a/c to work.

Thanks,
Robert

xsubdude99 · Sat Oct 23, 2010 12:58 pm

I ordered a 240v 40VA 24volt output transformer part number 025-18452-700 from Aberdeen and what they sent was a 240V 10VA 24volt output transformer part number 3400-3841, will this create a problem if I use it? It did fix the problem I was having with the heater but is this one too small to work over the long haul?

Robert · Sat Oct 23, 2010 2:41 pm

The old transformer was 3400-3841/A and it was replaced by 025-18452-700.

They are both listed as 20VA transformers.

Have you looked to see if you have another transformer in a control box or outside in your a/c condensing unit ?

As I stated previously, both the heat and the a/c require 24vac low voltage to work, so IF the a/c is working, then there must be a working transformer there somewhere.

IF so, then a 20VA would be fine and that is what both of the above are listed as.

Thanks,
Robert

xsubdude99 · Sat Oct 23, 2010 2:54 pm

The one that wasn't working supplied 24 volts across the heat side on the selector switch and then went to the sequencer. But replacing that transformer has fixed the problem with the heat. The part number that was listed on the side of the old transformer was 6214140. It had a tap for an input voltage of 208 as well as one for 240 and is listed on its side as a 40 VA transformer. The new one is only listed as a 10 VA