Replacement Sequencers - Comfort Aire AH

stephech

Hi I've got a broken 1988 air handler:

Comfort-Aire
"Central Electric Furnace"
B/M No '65BED420D65A' Ser No '28804139813'
'20/15' KW '70900/53900' BTU
AT '240/208' VAC '1' PH '60' Hz operation
Model No AH65BED420D

This is a two stage electric air furnace. There are two time delayed relays (sequencers) which control two 10kw heaters. Currently the two stage system is wired as a single stage. Each stage has a sequencer to switch on the fan when the heater is powered.

The system used to run with the fan in med-low, but recently the fan stopped operating in med-low and now only runs in high (controlled by the circulate control on the thermostat).

I checked the system, the fan relay works, and the motor sill runs in both med-low and high (by reversing the relay controls), but the fan will not run when the heaters are switched on. Without poking around with 240V's, I can only assume both heater sequencers are now broken.

Currently the system is working, by telling the programmable thermostat (TH8110) to switch on the circulator when it switches on the heat.

The part number of the sequencers are 8201-175 and 8201-180 according to the parts list.

1. Should I upgrade to a two-stage thermostat?
2. Could my problem be anything other then the two sequencers?
3. Doe anyone know where I can get replacement sequencers? are these generic or custom to Comfort-Aire?

A poor picture of the wiring diagram is attached.

Stephen, Ottawa, Canada

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kennzz05

as long as you havent gerry rigged something to make the fan come on your good. nothing wrong with the way you have it as long as theres no delay waiting for the fan to come on, i belive what youre saying is thru the programing mode you switched the stat to control the fan as opposed to the sequencer.
the seq. are generic might look a little differant just have to make sure it has enough contacts to do what you need it to do. if you decide to go that route but me, id leave it as is
i just reread your post why not swap the seq. make the one that didnt used to control the fan now run the fan
and the one that ran the fan b4 use that for second stage

pbservano

Check this sequencer out. Go to this website: http://customer.honeywell.com/techli...it/60-2051.pdf
You will need a technician to configure your system to work with this sequencer. It's available via the internet.

stephech

Hey Kennzz05,
Thanks for the info. It does seem to operating in the mean-time.
With the system as it is now, I have to manually rewire the fan to High when I want to run on A/C in the summer.
To address your question, my reading of the circuit diagram is that, wth the system wired for single stage, either heater sequencer 1 or 2 (TDR1 or TDR2) should make the fan come on. Since it doesn't do this, both must be bad. I just moved in here over the summer, and maybe one of the sequencers has been busted for ages.
I want to upgrade to a two-stage thermostat since this is suppose to save energy (I'm not sure about how much). If I want to avoid rewiring for the summer months, I need both sequencers to work, otherwise one would do.