Nordyne/Intertherm Model FEHB-017HA 5KW heater

[rjshenal]

Hello Fellow Techs

I'll try to be brief:
1. Noticed thermostat was loosely mounted on the wall so I tightened it. Only two wires on thermostat, red and white.

2. Sometimes 5KW heater comes on and sometimes it doesn't. I have an amp meter mounted on the 30amp CB that feeds it. 10KW heater works fine, amp probed it also.

3. Is this normal operation? I was thinking maybe this is caused by temperature measurement?? Or is this the job of the sequencer? Or is there a problem somewhere, maybe an over temp limit?

4. House warms up real nice when both heaters are running, but
takes longer when only the 10KW heater runs.

5. What is the job of the sequencer?

6. Maybe you can point me in the right direction, I was an electrician in a steel mill for 35 years.


Thank You much for your time.

rjshenal

[email protected]

[Robert]

Hi,

At very bottom of sequencer is the 24vac heater coils that control the sequencer timings.


On a call for heat, you should get 24-28vac at those.


Those are H terminals, should be printed on metal plate. Front and back is a set, H1/H2 and on other seq, stack front and back is H3/h4 and so on.

That should be it for yours. Once they're energized, the top and middle sets of contacts start closing within 30 to 90 seconds usually.


They're marked on the sequencers themselves on the sides.

M1/M2, M3/M4 and M5/M6 .



M1/M2 control 1 element and blower motor.

M3/M4 = one element

M5/M6 = one element



You have 3 elements, two on one assembly (10kw) and one on the other assembly(5kw).



ALL 3 should come on first to last and then de-energize in reverse, last to first.


Most likely the last set of contacts are not making and holding on each cycle.


Hope this helps.


If you need a parts price quote, let me know model number.



Thanks for inquiring.


Take care and best wishes,
Robert

[rjshenal]

Thank you Robert for the info

Then you are saying I may need a new sequencer, right? I'll have to dig in and do some trouble shooting then. Do you know where I can get a schematic for my furnace?(Nordyne model FEHB-017HA)

When I moved in my home there weren't any manuals for me to reference.

By the way there is an Intertherm thermostat with this system, that wouldn't cause me problems would it?
Again thanks much.

rjshenal

[email protected]

[Robert]

Hi,

It is ~most likely~ the sequencer. You can go here to order a

wiring diagram:

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


We may not have one for your model, but may have one for a
similar furnace with almost identical diagram.

Mark will tell you if it is not the very same and you can decide.



Thanks,
Robert