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[jamesbodeis]

 Hello everyone, great site, lots of info here. I will be hooking up a ridgewood owb soon. I currently have a fuel oil boiler with hot water heat with radiators. What I was hoping to try to do was have my current t-stat kick on the the pump for the loop in the house when it called for heat, but not the burner on the fuel oil furnace. Then have a second t-stat that would start the burner if the temp gets too low. Is that feasible? If not i may disable the burner on the fuel oil furnace and not run a back up and pray i dont have any issues. Thanks for any advice you may have/

[slimjim]

There is a much better way to do everything that you want to do without using a second thermostat and the oil burner is then an automatic.

[jamesbodeis]

I am open to any suggestions. Those were just my first thoughts on how to make it work.

[slimjim]

First, the oil boiler can be automatically shut off on water temp from the wood boiler by using the break on temp rise terminals on an aqua-stat, those terminals are used to interrupt the power (B-1) going to your burner motor.  By doing this all the rest of your wiring in the house stays the same and only uses the original thermostats, there really is no need to kill the loop circs but they can be controlled off the XX terminals inside the switching relay.

[jamesbodeis]

Cool. Thank you.

[jamesbodeis]

It looks like there is already an aquastat installed on my oil burner. Bonus.

[jamesbodeis]

Ok, now more of a plumbing question. My house is on one single loop. How do I tap into it to connect the exchanger? Can I just tee in on the supply and return lines?

[slimjim]

The aqua stat on your boiler is not the right one to use, it should be an add on and placed on the supply side of the wood boiler loop before the plate exchanger. Yes a tee on the supply and return can be used in the proper place, pay attention to ghost flow, not the best way to do it but it will work.

[jamesbodeis]

Ok. Thanks again for the help.

[jamesbodeis]

scratch that. Can i turn my aquastat on my fuel oil furnace down to say 120? That would keep it from coming on correct?

[slimjim]

Yes but that is way below what your system is designed for and it will not heat your home properly when using the oil boiler!

[jamesbodeis]

i understand that and appreciate all your help. Hopefully the fuel oil burner doesnt need to kick on all winter and it is a non issue. If i do have a failure of some sort on the wood boiler it will only take 1 miinute to return the fuel oil aquastat to its original setting. I am in no way saying anyone else should do it the way i have. A second aquastat is the correct way to install.