Furnace issue help: Update
Have a Coleman electric furnace model # 3500A820 It is stuck with the heat on. The only way I can stop it is turn off the power to the unit.
What I know. It's not the thermostat or the thermostat wires. The first thing I did was order a new thermostat. Before the thermostat arrived (should have done this first) I removed the old thermostat from the wall, disconnecting the wires. The furnace ran even with the wires disconnected. Then I went to the furnace and disconnected the thermostat wires there and it still ran. Thought a mouse may have gnawed the wires somewhere in the walls.
The power is off to the AC unit, but I disconnected the call wires from that as well, inside the house unit. No change from that. It's not just the fan stuck on anyway, it's the heat too. But I took this step anyway.
The unit has the AC, heat, standby, continuous fan and auto fan controls on the unit, not on the thermostat. None of these setting change what the unit is doing. It is stuck in heat mode. I've been turning the power off to the unit at night until I got some time. I'm off of work until Saturday so I have time to look into now.
Found this web site https://hvacpartstore.myshopify.com/collections/3500a812-coleman-electric-furnace-parts that has parts.
But not sure what I need or how to isolate the issue. I may figure it out once I start but I'll be ahead of the game is some of you folks could point me in the right direction.
Any help appreciated. Thanks in advance.
Update: It was the sequencer. Part arrived this morning. I went to a follow up appointment with the orthopedic surgeon and put the part in when I got home.
Thanks for the help.
What I know. It's not the thermostat or the thermostat wires. The first thing I did was order a new thermostat. Before the thermostat arrived (should have done this first) I removed the old thermostat from the wall, disconnecting the wires. The furnace ran even with the wires disconnected. Then I went to the furnace and disconnected the thermostat wires there and it still ran. Thought a mouse may have gnawed the wires somewhere in the walls.
The power is off to the AC unit, but I disconnected the call wires from that as well, inside the house unit. No change from that. It's not just the fan stuck on anyway, it's the heat too. But I took this step anyway.
The unit has the AC, heat, standby, continuous fan and auto fan controls on the unit, not on the thermostat. None of these setting change what the unit is doing. It is stuck in heat mode. I've been turning the power off to the unit at night until I got some time. I'm off of work until Saturday so I have time to look into now.
Found this web site https://hvacpartstore.myshopify.com/collections/3500a812-coleman-electric-furnace-parts that has parts.
But not sure what I need or how to isolate the issue. I may figure it out once I start but I'll be ahead of the game is some of you folks could point me in the right direction.
Any help appreciated. Thanks in advance.
Update: It was the sequencer. Part arrived this morning. I went to a follow up appointment with the orthopedic surgeon and put the part in when I got home.
Thanks for the help.
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I am going to go with item number 42 as bad - stuck relay. 0 -
how old ??? one of our houses still has a Coleman EVCON outside propane central unit...still seems to work OK but Coleman sold out this product to York long ago....time for a new unit ???? 0 -
A very quick Google search came up with a stuck sequencer (relay) as your problem. Sounds like a relatively easy and inexpensive fix for a DIYer. 0 -
If it was mine, I would first look at #42 (Thermostat relay) in your parts schematic. It acts like there are some relay contacts welded together somewhere.
Looks like a couple other guys had the same thought while I was getting this post one fingered out.[:0]0 -
27 years old, It is an Evcon. A new unit is needed, but not this year.
The whole control box was listed at $97, but is no longer available. So I may have to buy the individual modules and #42 could be it.0 -
quote:Originally posted by NeoBlackdog
A very quick Google search came up with a stuck sequencer (relay) as your problem. Sounds like a relatively easy and inexpensive fix for a DIYer.
I did a search and didn't find that. Can you post the link?0 -
If the contactor for the heat strips is stuck, the fan will run to keep the strips from overheating and melting. 0 -
Turn power off, open control compartment, gently tap on relay with plastic screwdriver handle.
Turn powere on. If unit restarts, replace relay. Supplyhouse.com is a good source for parts.
Relay may looks something like this:
https://www.mccombssupply.com/90-340-switching-relay-dpdt-24-volt-coil-also-replaces-honeywell-r8222d1014/?gclid=EAIaIQobChMIj7qzmdm93wIVWFuGCh382QlbEAQYGCABEgIZOfD_BwE0 -
quote:Originally posted by SCOUT5
quote:Originally posted by NeoBlackdog
A very quick Google search came up with a stuck sequencer (relay) as your problem. Sounds like a relatively easy and inexpensive fix for a DIYer.
I did a search and didn't find that. Can you post the link?
FWIW...
https://www.shopyourway.com/questions/1096443
I think I'd just replace both sequencers, if one's bad the other probably isn't far behind.0 -
If I remember correctly,a bad sequencer will cause one to click but not come on or run and not cut off.Either stuck open or closed. 0 -
quote:Originally posted by US Military Guy
I am going to go with item number 42 as bad - stuck relay.
Is there an echo in here?
[8D]0 -
Just add a relay with a thermostat to shut off power after reaching temp 
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quote:Originally posted by US Military Guy
quote:Originally posted by US Military Guy
I am going to go with item number 42 as bad - stuck relay.
Is there an echo in here?
[8D]
Yes..0 -
part # 10 sequencer not #42 stat relay
https://hvacpartstore.myshopify.com/collections/3500a812-coleman-electric-furnace-parts/products/3110-3571-coleman-2-pole-sequencer-h1-110-c1-1100 -
quote:Originally posted by pistoljim
part # 10 sequencer not #42 stat relay
https://hvacpartstore.myshopify.com/collections/3500a812-coleman-electric-furnace-parts/products/3110-3571-coleman-2-pole-sequencer-h1-110-c1-110
Ordered both, should be here tomorrow, I hope anyway.0 -
If neither one of those work and you still want to wait tree place it, order one of these. I know they work. It's an inline thermostat controlled extension cord. I use these on my propane torpedo heaters... They also have them in 240 volt...
https://morelectricheating.com/markel534109-markel-kt121-120-volt-inline-thermostat?gclid=Cj0KCQiAjZLhBRCAARIsAFHWpbHuwRHDMBj8onxXQdGgrXhp8C7w2DYfYGdlPJyQjd0vqdgF8BmrfDYaAh8YEALw_wcB0
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