UPDATE - Coleman 3500a812: Heat and blower staying on

[VAPOWELLS]

UPDATE:
I have Recently Replaced:

1. Sequencer
2. Both Limit Switchs
3. Blower Fan Relay
4. Control Box Wiring Harness
5. Furnace Wiring Harness
6. All Fuses ( 2x40 - 2x30 )

There is a distinct Humming/Buzzing coming from the Thermostat Reversing Relay.
With Breaker off i can turn on Breaker with Fan in Auto and System in Standby with expected results ( Nothing running) I can switch thru. placing the blower i the on position turn it on, back to auto turns off ( thermostat set to not call for heat) when i turn up heat sequencer clicks blower and elements turn on, and i have heat with blower, turn thermo down, blower and elements shut off ( blower for sure, elements i cant really tell but i think so) Then the buzzing/humming from Tstat rev. Relay begins, Blower kicks back on! only thing i can do is cut breaker off the it starts over again.

I tested the 240V to 24V Transformers and one has a output of 26V the other 29V.. I Think that's okay but cant find out for sure the correct threshold. If anyone knows what is acceptable pease let me know. Also how could 29 volts affect my system?

Wiring harnesses were replaced to eliminate the chance of a miswire or a bypass of some sort by the previous "A$$Hat" who rewired it with wire nuts. Reconnected as per the wiring diagram for furnace and control box and added molex connector to blower for proper connection. all connections were tripple checked by 2 different people to ensure accuracy.

Anyone with some direction would be appriciated
Thanks

Just don't know what else to do. Getting colder here with a unreliable furnace..........


Previous Post
I have a Coleman Evcon 3500a812 electric furnace.

Right now the blower stays on regardless of t-stat or control box settings. only difference is going to "cooling" position on control box, Fan speed picks up slightly. but in either fan auto/on or Heat/STBY/COOL positions blower runs. and any combination of these

Tstat set to call for heat or not, blower runs.

Also. it seams as if 1 of the 2 heating elements is running constantly. it blows warm air allways and if i set t-stat to call for heat it blows HOT air. then turn the tsta back down. air temp lowerers but is still warm.

The sequencer is brand new (S1-3110-3571) all connections are correct as far as i can tell.
( meaning identical to the one i pulled off (old M1 to new M1, M2-M2... H1... you get the idea))

I have the blower motor portion of my wiring Diagram rubbed off so i can only verify so much. Plus the previous owner bypassed the big wire connector due to a short it would appear.SO im looking at alot of wirenuts.... im pretty in the dark as to whats "Right"

Im thinking Limit switch, but im sick of thinking, can someone pleases help.

If you need more details please let me know.

Also if you have a copy of the wiring diagram for 3500a812 that may help be a great deal..

Thanks in advance!

Mike

[flcruising]

Here you can order wiring diagrams - http://www.mobilehomerepair.com/wireandparts.html

[VAPOWELLS]

@Aaron I did that for the diagrams, Thanks.

[flcruising]

I don't have a manual or wiring diagram for your unit, but when you mention the reversing relay, are you referring to the fan relay?

Can you pull the t-stat and report back the wires present?

Also, trying to clarify what the issue now is...
You have sufficient heat and the blower runs fine at initial call for heat. But once the the set-point is reached and the t-stat shuts off the furnace, the blower shuts off for a time and then comes back on indefinitely with/without heat?

[VAPOWELLS]

Replaced 240/24 furnace transformer.... everything works great..

[flcruising]

Glad you got it fixed.