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fredfillis · 11-05-2007, 08:46 AM

my fan ran all the time during summer so I just replaced the tstat a couple of weeks ago.

Now when I turn the heat on ... there is none. Again, fan runs all the time. On the LED it starts off with code 33 and then goes to 13, as advertised.

Kinda lost from here, the reset does not seem to do anything. Should the heat be "running" when I try to do the reset?

Any ideas what the problem could be here?

Thanks

fredfillis · 11-05-2007, 04:23 PM

FWIW, The tstat I used was a Hunter Autosaver 550

I've run the "diagnostics". According to the service manual, I disconnect the R terminal on the control board and then short the Test terminal to the Com. LED is supposed to go out, mine just flashes quickly. When I remove the short it goes back to Code 33.

#CARRIERMAN · 11-05-2007, 06:20 PM

Hi fredfillis

I would say that you have an open limit. Look on the back of the front panel of the furnace. On it you will see a legend that will tell you what each of the codes mean. I would venture to say you have either a rollout limit tripped or the vestibule limit is bad. If you have a voltmeter, turn the thermostat to the heat mode and check for voltage across the limits. If you show voltage at any one of the limits, that limit is open. Some of them have a reset button between the wires. However the vestibule limit does not, it is a automatic reset that has about a twelve trip life. If it is bad, I would reccomend checking the evaporator for blockage of air flow or use a better grade filter. Hope this helps, let us know if we can assist any further.

Good luck
Rusty

fredfillis · 11-05-2007, 06:42 PM

Thanks Rusty. I'll do those tests tomorrow. If the vestibule limit is bad, is it replaceable?

#CARRIERMAN · 11-05-2007, 06:58 PM

Hi fredfillis

Yes the vestibule limit is replaceable. As with any electrical component, shut the power off. This limit is in the middle of the furnace, its dimensions are about 2" wide by about 3 1/2" high. It will either be black, brown, or a beige color. They usually run about $12.00 to $25.00 dollars.

Good luck
Rusty

fredfillis · 11-06-2007, 04:25 PM

Both limits check out correctly. No voltage across either. Both measure less than 2 ohms. Both show 26v to ground.

Just for fun, I pulled the wires off each and shorted them, started the furnace and got LED codes 33 then 13 just as before. I'm thinking control board.