Thermostat..Aquastat...Controler of some sort ?

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Jesse-M

Jesse-M

Member
Sep 18, 2008
191
Columbia City, IN
I've had this issue since the day I started burning this thing. Right now what I have is a cheep thermostat that I added to my existing thermostat to basically bypass my existing. I leave the setting on off and just run the fan switch on auto, with the cheep thermostat hot wired to it. Works great until I'm not home in time to reload the boiler with fuel. When the water cools off, my heat turns into AC. I've got the wife schooled in the art of checking the water temp during the day ( via a meat thermometer stuck into the insulation around the pex in the garage at the HX ) and when it gets to a pre determined setting ( rare ) she turns the thermostat off. This works well also. The house will stay plenty warm the couple hours it takes me to get off work and reload.

Keep in mind this only takes place this time of year, when it gets cold she will maintain a fire ( via she sized rounds I keep stacked for her ) until I get home. Without storage, this sometimes becomes a problem when we, the family... are away for extended lengths of time ( Thanksgiving/Christmas ) My question is whats the best...cost effective way to take care of this problem? I've read that some of you have fancy thermostats for this, but I'm not well versed in the wiring of such an item, or possibly the cost? I've thought of using an aquastat to switch the power off of the blower motor when the water cools off....or some sort of controler to shut the blower down when the air cool off...The aquastat is the only thing I'm familiar with.


I guess my goal is to maintain the operation of my propane forced air furnace should I ever need to fire it on a "no wood emergency"
Anybody have the super simple, super cheep answer?
 
I installed a mechanical 12 hor timer on my fan only I se it to turn off just before all my wood is gone to help keep a load of hot coals to re light the fire They're available at Lowes 12 hr count down timer # 0136833 is the number from the box
 
A419 control from Johnson Controls. There is a temp sensor on a 4' wire or so you can attach to a pipe somwhere. It has a very simple relay inside, one normaly open and one normaly closed contact. You can set the setpoint temperature for it to turn on or turn off your blower. About $55 at Pexsupply.com

I'm using this to monitoring the water temp in my Garn. When it is over 130 (say), it will send power to another control such that a call for easy turns on my circs at the Garn. But if the temp is below 130, it will send power and the call for heat to the oil boiler. I have to use another switching relay for this (honeywell 182C). But, to just turn on/off your blower, the A419 should be able to do it alone....easy and cheap!
 
I ordered a PID temperature controller along with a thermocouple that was originally intended to measure exhaust pipe temperature of diesel trucks-- both available at modest cost from

www.auberins.com

The sensor will go in the flue pipe.

When starting a fire, I will set the temp. threshold low, and then raise it (easy to do) once the fire is lit. When there's no longer heat in the flue, it'll turn things off.
 
Intresting question, My system is just hooked up to 2 thremostats. So when the temps get down the gas furnace kicks in. But I guess the fan just runs steady then. Hmmm
 
Interesting question, My system is just hooked up to 2 thermostat's. So when the temps get down the gas furnace kicks in. But I guess the fan just runs steady then. Hmmm
 
Jesse,

If I'm understanding you right you have a heat exchanger in your furnace that is supplied with hot water from your boiler and you want your fan to blow through it when there is hot water available.

Your furnace transformer should have 4 leads on it ,R G Y W .

Your normal thermostat should connected to R and W.

If you connect another thermostat to R and G that will control your fan only,no need to have fan on auto.Now if you connect a Aquastat from the boiler in series with this thermostat the blower will only come on when the thermostat is calling for heat and the boiler temp is hot enough(what ever you determine to set aquastat for).

This way you can use both thermostats ,say you set the gas one at 60 and the boiler one for 70,your boiler will be proving your heat as long as you have sufficient temp from boiler but if some reason you don't have a hot boiler your gas thermostat will take over when your temp drops to 60.

This is all under the assumption that you are circulating water through the exchanger all the time,you could have it so the ciculator comes only when your are calling for heat but this would require the use of a relay.
 
Jeff S said:
Jesse,

If I'm understanding you right you have a heat exchanger in your furnace that is supplied with hot water from your boiler and you want your fan to blow through it when there is hot water available.

Your furnace transformer should have 4 leads on it ,R G Y W .

Your normal thermostat should connected to R and W.

If you connect another thermostat to R and G that will control your fan only,no need to have fan on auto.Now if you connect a Aquastat from the boiler in series with this thermostat the blower will only come on when the thermostat is calling for heat and the boiler temp is hot enough(what ever you determine to set aquastat for).

This way you can use both thermostats ,say you set the gas one at 60 and the boiler one for 70,your boiler will be proving your heat as long as you have sufficient temp from boiler but if some reason you don't have a hot boiler your gas thermostat will take over when your temp drops to 60.

This is all under the assumption that you are circulating water through the exchanger all the time,you could have it so the ciculator comes only when your are calling for heat but this would require the use of a relay.
Click to expand...

Jeff

You are correct on the operation of my setup. This idea is almost exactly what I was hoping for, one question I have right off the bat would be about the aquastat...The aquastats I run now ( damper and dump zone ) are wired 120, do they make different aquastats for 24?
 
Jeff S said:
Jesse,

If I'm understanding you right you have a heat exchanger in your furnace that is supplied with hot water from your boiler and you want your fan to blow through it when there is hot water available.

Your furnace transformer should have 4 leads on it ,R G Y W .

Your normal thermostat should connected to R and W.

If you connect another thermostat to R and G that will control your fan only,no need to have fan on auto.Now if you connect a Aquastat from the boiler in series with this thermostat the blower will only come on when the thermostat is calling for heat and the boiler temp is hot enough(what ever you determine to set aquastat for).

This way you can use both thermostats ,say you set the gas one at 60 and the boiler one for 70,your boiler will be proving your heat as long as you have sufficient temp from boiler but if some reason you don't have a hot boiler your gas thermostat will take over when your temp drops to 60.

This is all under the assumption that you are circulating water through the exchanger all the time,you could have it so the ciculator comes only when your are calling for heat but this would require the use of a relay.
Click to expand...

You don't want to pump water thru the HX 24/7. When the wood is out and the propane portion is providing heat you will also be heating up your cold boiler water using the propane furnace (thru the HX).
 
Jeff S said:
Jesse,

If I'm understanding you right you have a heat exchanger in your furnace that is supplied with hot water from your boiler and you want your fan to blow through it when there is hot water available.

Your furnace transformer should have 4 leads on it ,R G Y W .

Your normal thermostat should connected to R and W.

If you connect another thermostat to R and G that will control your fan only,no need to have fan on auto.Now if you connect a Aquastat from the boiler in series with this thermostat the blower will only come on when the thermostat is calling for heat and the boiler temp is hot enough(what ever you determine to set aquastat for).

This way you can use both thermostats ,say you set the gas one at 60 and the boiler one for 70,your boiler will be proving your heat as long as you have sufficient temp from boiler but if some reason you don't have a hot boiler your gas thermostat will take over when your temp drops to 60.

This is all under the assumption that you are circulating water through the exchanger all the time,you could have it so the ciculator comes only when your are calling for heat but this would require the use of a relay.
Click to expand...

You don't want to pump water thru the HX 24/7. When the wood is out and the propane portion is providing heat you will also be heating up your cold boiler water using the propane furnace (thru the HX).
 
huskers said:
You don't want to pump water thru the HX 24/7. When the wood is out and the propane portion is providing heat you will also be heating up your cold boiler water using the propane furnace (thru the HX).
Click to expand...

Good point....When I do use my furnace, I turn the pump off just for that reason.
 
Jesse what Aquastat are you using, the one I'm thinking of are made by Honeywell and are basically a temperature controlled relay,in other words they are acting as a switch and could be used for either 24v or 120v.
 
Jeff S said:
Jesse what Aquastat are you using, the one I'm thinking of are made by Honeywell and are basically a temperature controlled relay,in other words they are acting as a switch and could be used for either 24v or 120v.
Click to expand...

I'll have to look to see the exact aquastats I have but I'm almost positive they are simple, temp controlled switches. Thanks for the info...I will look at my original "hot wired" thermostat and see if I can hook it up the way you suggested.
 
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