Ot: house thermostat question.

I heat my house with a indoor wood boiler, or hot water stove. I also have a fire place insert woodstove, then I have a Utica oil boiler for backup. Well I have been using the kitchen insert to heat the house and cook apples down on for apple sauce. It's been pretty cold and windy and the insert can't really heat the whole house, 5 bedrooms, ect. So I fired up the oil boiler, I set the thermostat to 69, I noticed it was getting warm in the house and so did the wife, who's always cold. I look at thermostat and it says 71, but boiler kept running, I change battery's in thermo and still keeps running. Well I took the up stairs thermo and put it in the 1st floor thermostat and boiler finally shut off?? I guess the lux thermo is bad. Can anyone recommend a good digital thermostat that is lighted? One thing I hated about these lux ones was you can't read if it the dark. This is what I have now. Thanks for any advice. J

Honeywell has always served me well!

Check and see if it is set right. You can adjust the digitals as to how far below set they go before kicking in and how far above before kicking off. I had no idea until I was bored and read the directions that came with this one.

Jay, I've installed many of these BIG BLUE's by White Rodgers. User friendly programming and they come available for single and dual stage heating and cooling. Nice thermostats. I have one in my own place. They have a nice backlite on them you can leave on all the time or set it to come on whenever you touch the surface.

The oil fired boiler will run untill its water is X degrees, where ever it is set at on the aquastat, if 160? it will run till that sensor hits 161, no mater what you have on the wall. A side arm domestic H2O makes this ever more confusing... my bet there is nothing wrong here...

No, the boiler should only fire when the thermostat calls for heat not the aquastat. My runs with the thermostat in the off position.

Two things:

First, thermostats have an "anticipator" function, which shuts off the furnace before the set temperature is reached. That's because the furnace normally runs a minute or two after the thermostat cuts off, during which time the temperature will rise a bit. Most thermostats are set at the factory to work with forced-air furnaces and need to be readjusted for boilers. Because there's so much hot water in the pipes when the boiler cuts off, the anticipator needs to shut off a hydronic system much earlier than a furnace. If your thermostat has a non-adjustable anticipator, you may need to change it out for one that does, like one of the popular round Honeywell units.

Second, thermostats on hot water systems don't usually directly control the boiler. Instead, they open and close the zone valves. The zone valve has a switch on it that starts the circulation pump and fires up the boiler once the valve is open. If you have a sticking zone valve, it won't matter what you set the thermostat to. Typically what happens is one valve will be stuck and the valve for a different zone will cycle. I'm only familiar with the Honeywell valves; on these units there's a lever that sticks out of the control box for manually opening the valves and to indicate the valve position. You can tell if a valve is working right by turning up each zone with the others turned down and making sure that only the one zone is circulating.

I don't have zone valves, the thermostat is wired right to the boiler. I figured out the problem, but thanks for the help.

>I figured out the problem

Are you going to share that information?

See my above post