Print

[yotehunter66]

What are the pros and cons of having an aquastat vs a thermostat? I'm looking at maybe swapping out the aquastat for a thermostat and wanted to here your opinions.

[Rockarosa]

I have an Empyre 250 made by Pro-Fab. My furnace is oil fired hot water heat, heating a 2800  sq. ft. old  farmhouse. I have a thermostat for my oil and right next to it is thermostat for OWB. I leave my oil thermostat turned all the way down unless I decide to go away for the weekend. Then I turn my OWB thermostst down and unplug the pump and turn oil thermostat up.  I really like this set-up and my furnace has paid for itself in the 4 years since I installed it.

[muffin]

Are these not two completely seperate items.  A thermostat controls the air temperature in the house by commanding some othersystem to either heat or cool.  An aquastate controls the use of a water system.  So, for instance, you could use an aquastate to determine whether you have hot water in your boiler, or wether it should use the oil furnace. 

Some use two thermostats and simply set the OWB above the oil/gass furnace.  Then if the fire goes out or something, the oil/gas will kick in when the temperature continues to drop since there is not hot water.

[yotehunter66]

They are two separate control devices. There is one installed on the boiler to maintain the water temp between 160-180 degrees. There has also been one installed on the supply line to control when the furnace will be used. I've read that some people prefer to use two thermostats rather than an aquastat for furnace control. I wanted to here the reasoning for using one or the other.

[Hydronix]

There aren't any pros or cons. You use the correct control for the particular application. The T-stat tells the heating device what parameters to cycle on and off, and the aquastat controls the boilers temperature control functions , or acts as a safety limiting device.

[RSI]

If you use the aquastat you are more likely to burn some gas if the fire goes out.
With 2 thermostats you can set the one for the gas furnace lower so the house would cool down some before burning any gas.

I personally would rather let the house temperature drop than waste gas. Also, if the fire goes out for some reason, (forgot to turn switch on, wood bridged, etc) you will know something is wrong because you are getting cold air out of the vents.

[yotehunter66]

There aren't any pros or cons. You use the correct control for the particular application. The T-stat tells the heating device what parameters to cycle on and off, and the aquastat controls the boilers temperature control functions , or acts as a safety limiting device.

While I agree with what you are saying, I guess what I'm trying to figure out is if I need two aquastats. There is already one installed on the wood burner for temp control. I do not think the one installed by my propane furnace is for safety. I was looking to see if there was a benefit to having two thermostats for control since that seems to give me more flexibility with controlling when my furnace kicks on.

[egnuol]

Adding to the post. I heat two buildings with one furnace and use the aquastat for the furnace control and thermostats in the buildings for heat regulation. One of my shops has an oil furnace for backup (I use that fan for the heat exchanger in the plenmum) when I can't tend the fire. I have also added controls to the fans so when the water temperature drops below 50 degrees F. the fans will shut off and not throw cold air and maybe prolong water heat. But there is two differant controls needed for correct operation.

[RSI]

There seems to be some confusion here about what the original post was about. It had nothing to do with the aquastat on the boiler. It was about using an aquastat in the house strapped on a pipe to switch the wall thermostat automatically between gas and wood heat.

[egnuol]

66,

I can understand having separate controls for two heating systems. That's pretty much what I was saying about the control to shut off my fans when the water temperature drops. Since you already have a backup furnace you have the thermostat and thats all you need. What I have learned what is good for me maybe not good for you because of your time at home.. I have had two thremostats for years and it works well. I guess all the 2nd aquastat is doing is to tell the gas furnace it is needed. Darrel

[yotehunter66]

There seems to be some confusion here about what the original post was about. It had nothing to do with the aquastat on the boiler. It was about using an aquastat in the house strapped on a pipe to switch the wall thermostat automatically between gas and wood heat.

Yes, that is what I was trying to ask. If one was better than the other. I think I am leaning toward adding a second thermostat. Thanks for the replies.