AC strip heater trips its breaker

[sreigle]

Last Fall I installed a strip heater in our front AC, a Coleman Polar Mach unit. It is the heater designed for that unit. It has its own resettable breaker although it requires pushing a button to reset it, but I have to remove some screws, then remove the ceiling surround unit plus four screws way up inside the fabric plenum before I can get to that button.

We used the heater a few times, then it quit heating. I had to take it all apart and push the button.

We then used it a few more times, maybe a couple of weeks, and it apparently popped again. Soon I'll break down and take it apart again but it's really a pain.

Anyone have an idea what is causing this thing to pop the breaker? I know it is because it's drawing too much current, probably overheating. And that probably means inadequate airflow. But why? It's a simple unit and mounts with just a builtin clamp and setscrew. And the cord to the plug is too short to put the unit anywhere but where it's supposed to be mounted.

Any ideas?

I don't know if this picture is of any value but it looks like this. You can barely see the reset button on the top of the box. It sits in what I think is the return air chamber, the only place the cord will reach.


Thanks.

[rak]

Hi Steve,
If the voltage in your unit goes low it will cause the unit to draw more current and trip the breaker. The formula P (power) = Voltage x current. So if the voltage goes down the current goes up to maintain the same power. I don't know if this helps but might explain what is happing.
Dick

[jimcol]

Steve, rak's explanation of what caused it is as good as any. Can't tell by looking at the picture but I'm guessing it is a thermal reset breaker like you have on the bottom of a garbage disposal or small compressor motor. My experience with these are once they pop they become very prone to pop again and again. Only fix is to replace it. Jim

[camper4]

I assume the air flow is not restricted in any way. Like partially plugged filter?
I agree with both other responses and know of those thermal overload protectors, breaker, failing often after they blow once. It may need replacing.

[exav8tr]

Steve, If the power in your rig is dropping have you considered something like the Hughes Autoformer to provide a more constant powert source. We have the portable one we cable lock to the CG power pedestal. We don't have a heat strip but since we bought the Hughes our power problems seem to have dissapeared, except when we forget we are on 30 amp power and one of us turns the MW on while the electric heater is going. (Nothing cures stupid, you know!!)

Phil

[firetrucker]

If that's a resistance heater, which I imagine it is, then low voltage will reduce the power output because of lower current (resistance stays constant, not the power). I'd suspect that you've got a bad breaker.

Bob

[Ozz]

Probably a weak breaker

[clarkandsheila]

Weak breaker or loose connections at the breaker causing the terminals to heat which heats and trips the breaker.
Firetrucker is correct.

[sreigle]

Thanks to all. You have probably nailed it. The breaker is probably thermal and is manual reset by pressing the button. It's only popped twice because I haven't yet reset it after the second time it popped.

I do have a Hughes autoformer but was not using it at the time of the breaker popping, either time. We were in our "home park" which has good power so I was comfortable with not using the autoformer. Normally I would use it anyhow but we were there until after Christmas, which means ice and snow, and I decided I didn't want to deal with disconnecting it in the ice and snow. So power might have been the problem.

I'm pretty good about keeping filters clean but they naturally do get partially clogged before I clean them. So that could contribute, as well.

Since it has only popped twice I will not yet replace that breaker but if it persists then I may see if that's something I can do. I haven't really looked at it to see how this thing comes apart. When I pull it out I'll check that.

Thanks again. It's frustrating because we were really enjoying it when it worked.

[Rondo]

Steve-- You're in "warm country"-- just think if you were up here in the Midwest yet and having to use the heater strip!! It's a balmy 37* as I type this out! Oh the joys of winter in Nebraska!!

[sreigle]

Ron, come on down. It's time for us long lost twins to get together again, anyhow. But I see you just got more snow so I'm NOT coming that way, you'll need to come south!