# Electric Heater - Sequencer and Thermostat Problems



## birlbond (May 12, 2010)

All,

I have had ongoing problems with my electric heater/AC unit for the past 6 months or so.

One of the problems is that the heater will stay on even when the thermostat is set to Cool.  The heater sequencer has been replaced twice now and both of the ones that were replaced appeared to be broken: the top part looked like it had been burnt and one of the wires connected to it had some of the insulation melted off.  Once replaced the heater would turn off and seems to operate properly.

The second problem is that the fan wouldn't come on in "Auto" mode on the thermostat.  The thermostat has been replaced twice now, and again, the problem seems to be solved by this each time.

Today the thermostat and sequencer were replaced again, but I have a feeling they are just going to break again.  Are these problems related?  What is going on?

Any ideas are appreciated - thanks in advance!

Will


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## Wuzzat? (May 12, 2010)

birlbond said:


> One of the problems is that the heater will stay on even when the thermostat is set to Cool.
> 1
> The heater sequencer has been replaced twice now and both of the ones that were replaced appeared to be broken: the top part looked like it had been burnt and one of the wires connected to it had some of the insulation melted off.  Once replaced the heater would turn off and seems to operate properly.
> 2
> ...


Post a schematic; it's pasted on the inside of one of the panels.

1 Since this problem is reproducible it should be easy to troubleshoot.

2 If it works for a while and then fails the root cause of the failure hasn't been found.

3 See #1

4 I think you're right, see #2.


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