Nordyne E2EH 012HA Intermittent Problem

[piper468]

I posted this problem with my Mother in laws furnace back in April and it continues.

I've replaced the sequencer, T-stat, transformer and limit switch within the last eight months. The furnace runs for a while and then it quits and doesn't start. Yesterday I removed the new T-stat and jumped the wires (red-white) and it started. The transformer output is 16.8 VAC while it calls for heat. Could the low voltage keep it from starting normally? I replaced the transformer back in March so I don't know if its bad.

The voltage is 120 VAC to all 4 elements. How long do these elements last in electric furnaces? One interesting side note is that when its running I hear a faint single click every 5 seconds or so. Seems to be coming form the limit switch or elements. Is this normal?

Does this furnace have a fan relay and if so where would it be? I've tried everything that I know and so far this thing is winning. Please give me some insight. Thanks

Russell

[Robert]

Hi Russell,

Check to be sure you have 240vac across primary-line side of transformer. IF so, then you must have at least 24vac across secondary-load side.


Transformer, sequencer and fan relay will be in bottom control panel.


At each element, there will be a terminal at each end on a white ceramic insulator.


You should have 120vac to ground from each and 240vac across them after 45 secs to a minute after call for heat.


Elements can last several years and then some last only a few, just depends.


Thanks,
Robert

[piper468]

Hello robert,

The transformer tested bad. I dissconnected the secondary leads and with 240VAC input I was getting about 1.5 and 2.5 VAC out. I put the old transformer in place and the results were similar. Shouldn't I get 22-28VAC on the secondary side everytime when there's 240VAC input? Whats weird is it will work that way.

The upper and lower elements ohmed out good but when the furnace is running they cycled on and off about every 20 seconds. I had my meter across them and it would read 240VAC and after 20sec or so it would be zero. Seems like that's to often but I'm not sure.

The new sequencer had about 40 ohms across the bi-metalic strip and the manual said it should be 70-90 ohms. The old one tested at 70 ohms so I put it back in. Also the M1-M2, M3-M4 switches were open as normal. Would the low voltage from the transformer give me control issues on the sequencer?

All other components tested fine. IE; limit switch, fan switch and motor. Seems like a simple system but I can't get a handle on it. The furnace will start and run normal after I finish working on it but after a few hours or sometimes days it will stop. Seems to have issues with restarting. Anymore help would be much appreciated.

[Robert]

Be sure your meter is accurate because the furnace will not work without 24vac low voltage circuit.


Thanks,
Robert

[piper468]

The multimeter is a Fluke 73. Fairly new and accurate. I checked voltage again on the transformer and I get 1.5 VAC on the gray wire going to the sequencer and 2.5 VAC on the purple wire going to the white wire on the T-stat. Soon after I checked it the furnace started up. Are you sure that this E2EH 012HA furnace won't run without the 22-28 VAC?

Could you please answer some of my previous questions in this post? Still don't understand why this thing runs good for a while and then quits. The only piece left in the puzzle is the transformer and it's about eight months old. But I find out quite often that parts can be bad from stock.

Regards

Russell

[Robert]

Hi Russell,

You are testing the wrong transformer wires. As for as answering your questions, I am answering them in the manner that they need addressing. No furnace, yours or otherwise will work without 24vac low voltage circuit.

August marked my 31st year in hvac service -repair-installation that has covered everything from window shakers to industrial plants. So yes I am quite certain that it will not run without the voltage.


Thanks,
Robert