Aquastat Controls

[NCPABill]

Thanks to all of you for your help (particularly for taking your time to post all of this reading information.)

I have begun to install a Biomass 40 with a 500 gallon storage system. My boiler circulator will be set to run (planned) by the boiler only to the storage tank only. My hope is to run wide open until the return water gets to a point which will force shut off of the boiler.

My zone valves and house heat circulator will only when the call for heat is sent. This should be a fairly simple move from the existing gas boiler to the new circulator (I hope).

My real quandry is how to wire the gas boiler for an emergency-only back-up, like if I was in a car accident and couldn't get home to fill it up. I think I would like to put an aquastat on the tank to sense a low temperature, thus turning on the gas boiler to heat the water in the tank to a certain point, then sends the signal to turn the gas boiler off. The house may or may not be calling for heat at that moment.

Any advice for a newbie-getting-not-quite-as-new boiler installer

 

[mikefrommaine]

I too am another not so new newbie so... Trust me or not. But i would think an aqua stat on the storage tank to control the gas boiler would be the way to go. Set it to open on tank rise, (turning off the gas boiler) and to close when the tank drops below a useable temp.

 

[ohbie1]

I use an aquastat in my storage tank to turn on my backup oil boiler and it works fine. My oil boiler heats the house directly and not the storage tank. I don't think heating your storage tank with the gas boiler is as efficient as using it to heat the house directly (when the house calls for heat). If you do decide to heat storage with the gas, then I would definitely add something in that aquastat circuit so that when you do fire up the wood boiler, the gas shuts off. It could be just a switch that you throw until the tank heats up. If you want it more automatic (and complex) you could use some type of sensor to detect boiler heat (possibly on the chimney) which in series with the aquastat circuit woul kill the gas boiler as soon as the chimney got warm.

 

[[email protected]]

I recently installed a Biomass 40 system in my home with 500 gallons of pressurized storage. I used a Honeywell aquastat with a long well set to break on low temps at the tank head. The aquastat is wired in series with the end switch on a Taco Zone valve control box, and then to the TT terminals of a propane boiler. If one of the thermostats calls for heat, the end switch is closed. If the storage aquastat is closed due to cold temps in the tank, the circuit is complete and the propane boiler is activated.

 

[Clarkbug]

I am setting up a similar system, and Im going to use the EMC control to accomplish just what you are talking about. CozyHeat (site sponsor) has them for $100, but its really just a transformer, some relays, a switch and some terminal strips. So if you are handy and want to play, you can probably make one cheaper. But the system really does exactly what everyone above is talking about by monitoring an aquastat that you install on your storage tanks.

 

[bpirger]

I use a Johnson Controls a419 to do the same thing. If my Garn drops below a set point temperature, it sends power to the boiler so the call for heat will be answered by the boiler....Then I just heat the house, not the 1500 gallons outside in the Garn barn. My plan is to get a timer setup so that if the power is sent to the boiler, i.e. GARN is too cool to heat, it will still run my pumps outside for a few minutes every hour or so to make sure nothing buried in the ground freezes.

 

[NCPABill]

Thanks for the input. I sincerely appreciate the help - and it is much needed. I'm fairly mechanical, but controls seem to escape me completely. I can read and read and it only confuses me more.

I have a Honeywell L6006C aquastat. It would seem that (without any thermostats) I would run power to the aquastat, then to the boiler (which is now wired, a simple remove and replace wiring job?).

http://s3.pexsupply.com/manuals/1303919167040/54523_PROD_FILE.pdf

Is this the right aquastat?

Does my concept of wiring come even close to actuality?

Ohbie1,
I'm not worried about efficiency in that my tank supply and heat to house are close - that and the fact that the expectation to to run the gas boiler for emergency backup only. I'm hoping that I can set the aquastat to turn the boiler on at 80 degree tank temps and off at 100ish. This is desired for freeze protection only. In theory, the house circulator would be running by now, and would continue to run indefinitely (until the house reaches the setpoint of 72 degree temperatures, which will be when I start a fire and heat the tank up all the way. Thinking out loud, I could wire in a switch to lockout this aquastat / gas boiler if that would help simplify the situation.

Thanks again, and I really mean it. I really am thankful for all of the information posted.

Bill