Thermostat help ???

[crs7200]

OK. lets see if I can explain this correctly.

I have had a outdoor wood boiler for 9 years. The heat exchanger is in the plenum of my forced air furnace,
When the house is calling for heat, the only thing that runs in the forced air furnace is the blower fan to push the heat thru the house. Basic operation...

My issue. I have a regular dial thermostat and I don't like it. I want more control of the heat. I want a programmable t-stat. When the OWB was installed, the installer put a 120/240V T-stat on and it is hooked into a junction box on the furnace. It is not hooked onto the control box by the burner.

Question #1. Is this the normal way of hooking up a second t-stat to run just the blower?

Question #2. Is there a Programmable t-stat that I can install on that existing line that will work to run just the
blower and if so which one? I have looked at many, and most say that they are not compatible with
120/240V. I want one with programmable swing so I can choose how much differential I can have
between on and off.

Many places will not let you return parts such as these, so I want to be sure that it will work correctly before purchasing one.

Thanks in advance for any help... B

 

[brant2000]

There's been a number of threads discussing options to do this. The way my system operates is that my circ is always providing flow to the HX in my plenum and I use a second wall mounted thermostat to operate the furnace blower, as necessary. To do this, I simply tied a cheapo heating only thermostat in parallel with the blower relay coming from my furnace (heat pump). As long as you close the circuit to that relay (and I believe most furnaces provide a relay to engage the blower only) it will work. No power is even required for that thermostat to operate, assuming you can find a battery powered (not just backup) programmable thermostat.

 

[crs7200]

There's been a number of threads discussing options to do this. The way my system operates is that my circ is always providing flow to the HX in my plenum and I use a second wall mounted thermostat to operate the furnace blower, as necessary. To do this, I simply tied a cheapo heating only thermostat in parallel with the blower relay coming from my furnace (heat pump). As long as you close the circuit to that relay (and I believe most furnaces provide a relay to engage the blower only) it will work. No power is even required for that thermostat to operate, assuming you can find a battery powered (not just backup) programmable thermostat.

My system is operating the same as yours. Pump always on and 2nd cheapo t-stat running just the blower.

What I want to know is if there is a reason that the installer used a line voltage t-stat to do this? Couldn't he have used a normal lower voltage t-stat to do the same thing and hook it up differently?

I know very little of wiring. Enough to do the basics, but telling me to run the t-stat in parallel with the blower relay as long as you close the circuit to that relay, is like telling me how to land the space shuttle Sorry. Over my head.

Here are 2 pics of my oil furnace.

The first is where the original oil furnace t-stat is connected.

The 2nd is where they wired the blower only t-stat that is line voltage. The big yellow wire is the one they ran from the t-stat.

From this, can you tell me how to wire a normal lower voltage programmable t-stat to run just the blower???
If you can...Thanks. If not, I guess I will have to call someone. LOL

 

[Clarkbug]

The reason he wired it this way is that it avoids costs and time for him...

I'm guessing that your oil furnace no longer works if you try to run it off oil?

The 120v stat can handle cycling the fan, vs having to fiddle with relays and other wiring. You have a few options here, but it depends on if you want to use your oil ever again.

 

[crs7200]

The reason he wired it this way is that it avoids costs and time for him...

I'm guessing that your oil furnace no longer works if you try to run it off oil?

The 120v stat can handle cycling the fan, vs having to fiddle with relays and other wiring. You have a few options here, but it depends on if you want to use your oil ever again.[/quotees,

The reason he wired it this way is that it avoids costs and time for him...

I'm guessing that your oil furnace no longer works if you try to run it off oil?

The 120v stat can handle cycling the fan, vs having to fiddle with relays and other wiring. You have a few options here, but it depends on if you want to use your oil ever again.

Yes, the oil furnace still works fine. It runs off the original t-stat and I use it in the spring and fall when the heat is only on once or twice a day to take the chill out of the house. So... yes, I want the oil furnace to work.

 

[crs7200]

??

 

[tomc585]

Question 1, yes, this is a very typical and economical installation for a dual use setup such as yours. They are very reliable and easy to trouble shoot if need be.
Question 2, yes. Google line voltage programmable thermostat. $60-90

 

[brant2000]

This goes into territory that I don't have a lot of experience with, but I believe you would probably want to get a 24v transformer (unless you could steal 24v from your honeywell controller) and then a 24v blower relay. Like TomC mentioned though, you'd probably be better off just trying to find a line voltage programmable thermostat.