replacing old thermostats oil furnace (floor, air conditioning, water heater, living room)

[peanut24]

Hi there~
In a former home with a Gas furnace/central air conditioning I replaced the old 1980's thermostat with a new digital one, it was fairly easy.

Now I am in an older home with an oil furnace, no air conditioning. There are 2 zones/2thermostats from the 1950's. One is upstairs, one on the main floor. They are "Honeywell Chromotherm" thermostats, big and rectangle, with some sort of clock on it and a ticking/running sound all the time. I want to replace them for better efficiency and because the "running" sound is annoying. My question is..is it pretty much the same thing to swap these out as my previous experience or is there any other issues that could come up dealing with an oil furnace?

Thanks in advance!

[chet everett]

....but I would do more research just to be on the safe side.

Some homes wih hydronic heat also have the domestic hot water tied into the main heating plant. It may be that the "chronol-therm" is something that makes sure you have hot water for a morning shower or some other non- standrard use.

The vast majority of residential themrostats use a simple 24v activation to tell a rely on the heating plant to make heat. The more sophisticated heating plants may have a whole sequence of events that need to controlled by electronics -- power burners, fans, dampers, recirc pumps. I doubt the thermostat matters much... I suspect that a setback thermostat is really a pain for most older hydronic systems. They typically have a pretty good "coasting phase" so that as the water in the system does not get too cool the warm-up is nice and even. If the set back let's the whole system's water supply get to a very low temp it'll take much longer to achieve the set temp. I would want a pro out to verify the value of setting an older system back. You wil almost certainly save much more money with a newer biurner fitted to the existing plant.

I know that some multi-stage HVAC systems, especially those with advanced heat pumps, might need a specialized thermostat, but even then I doubt a mechanical clock needs to be part of the mix.

[peanut24]

interesting...the water heater is part of the furnace. furnace is newer, last 10 years or so, not sure why the previous owners never updated the thermostat, maybe because there is more to it. The "clock" part upstairs is taped down so it does not move and there is no "ticking/running" sound, it was like that when we moved in. just the main floor is making noise. If it was not a big deal to tape it down maybe it is not a big deal...I have a feeling I am not educated enough with this type of heating service and will probably have someone come out. thanks!

[akck]

It is as simple as your previous gas furnace, so you can do it. I've done my oil furnace, switching to a programmable thermostat. Your hot water shouldn't be part of it as any thermostat would be located with your hot water storage tank.

[procfreq]

Agreed. We just replaced our thermostats a couple months ago. Oil heat with hot water storage tank. Zero issues with the upgrade. Piece of cake.

[lbross000]

We recently purchased a home with a gas fired boiler with hot water base boards the home has 3 zones this being my first experience with a system like this my question is does the primary zone control all the other zones even though I have 3 thermostats the best example I can give is the primary being for the kitchen living room den And dineing room can be set at 70 but if I try to rais the second zone for the bedrooms higher say to 72 it will go no higher than 70 is this normal ?