I noticed last night that my heat (hot water through baseboards) was on even though I had my thermostat set all the way down.  Does this sound like a faulty thermostat?  Right by the furnace, there is a switch (looks like a light switch) that will stop the furnace from coming on.  Is it okay to turn it off?  Also, this furnace automatically lights the pilot.  This may seem stupid, but I really don't know much about these things.  When it comes to natural gas, I don't want to screw around.  Any help would be greatly appreciated.

Thanks,
Chimborazo

Two guys meet each other at 6,000' altitude--one going up and the othergoing down.

The guy going down asks, "Hey, do you know anything about skydiving"

The guy going up replies, "No.  Do you know anything about gas water heaters?"

Sorry, I couldn't resist.

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If you have one thermostat the controls the whole house, and the heat's running even with it turned all the way down, you need a new thermostat.  Or, you could be getting residual heat in the system if you just turned it down in the last few hours.

It would be okay to turn switch off, but that would not fix the problem if there is one. It sounds like the switch is the power going to the furnace. The thermostat may or may not be faulty depending on how the system is set up. Was it the pump that was running or the burner or were they both running? Some systems run the pump all the time and cycle the burner with the thermostat.

It's hard to tell exactly what your problem is, however, here are a few thoughts---
a) It could be the thermostat, but, I'd bet against that.  Most thermostats are "bulletproof", especially the Honeywell round ones.  Try taking the thermostat off of the wall---disconnect it from the backplate----that will disengage the low voltage wires and if the furnace doesn't turn off, then you'll know that the thermostat is not the problem.
b) Try turning your power switch off---waiting 5 or 10 minutes and then turning it back on again.  Sometimes, that is the way to reset the control module which controls the furnace.
c) In my (albeit, limited) experience, what "goes" on modern, natural gas furnaces are usually either the hot surface ignitor (certainly not your problem) or the control module.
d) Do you have an instrucional manual or booklet for the furnace?  Check it and/or look up the manufacturer on the web and then, telephone them for assistance.

I was wondering if maybe its just the water circulating pump running. Is the furnace actually turning on the burners and heating the water up when the thermostats all the way down?

Thanks for your responses.  It's not just the pump running.  The burner was actually coming on...just like if I had the thermostat set to 80 degrees.  Right now I have the switch off, but I'm not sure where to go from here.

Thanks,
Chimborazo

I am not trying to be a smart ass but if you do not know which way to go at this point, I think you should call a professional. Make sure they "train" you while they are there on what they are doing. I learned a great deal about the wiring in my house this way.  [:)]

Probably bugged the shit out of the electrician, but it was my dime, not his.

Yeah, you're right.  Damn, I hate having to take time off work for this stuff.

A couple quick things for you to check.

Does your furnace have more than one zone?  
(upstairs on one thermostat and downstairs on another)  If so are they both turned down?


If the above doesn't apply, and you are comfortable doing so, remove the wires for the thermostat, on the furnace side , and see if the furnace is still running.  if it shuts down then it is either a thermostat or the wires could have a short...  If it is still on after that, then there are way too many different configuration of furnaces for me to tell you what to do next, you would need to have a heating person look at it.

BTW. If you find a bed thermostat, make sure you take a voltage reading off the wires because there are a few different setups...  24V is the most common  

hope this helps

[size=4]OR[/size=4], if you know the brand of thermostat you have, give them a call. All the good companies run a seven day customer service line, and they have web sites to get the phone number from.