Second floor radiators

[adcman]

Greetings all, first post here. I am currently installing cast iron radiators in my 137 year old farmhouse, to heat with a OWB. How do I stop the water from siphoning back down to the boiler in the return lines, from the second floor radiators, when the pump stops? I have a non- pressurized system.

 

[stee6043]

If you do a quick search I think you'll find several posts on this topic. Generally speaking I don't think it's typically advisable to have your boiler located lower than your highest heating appliance in a non-pressurized system. You'll end up with air in your lines every time the pump stops. Some folks have made this type of setup work but I think it's far from "most desirable".

 

[Eric Johnson]

You might want to consider isolating your house system from the OWB with a flat plate heat exchanger. That way your house system would be pressurized, while your OWB would not. This would involve another pump and some other hardware (pressure tank, air scoop, etc., but it would solve your problem and might give you a bit more flexibility.

 

[adcman]

Thanks for the information. I was thinking about extending a pipe upwards, (higher than the highest radiator) from my overflow on the boiler, but am concerned about freezing.

 

[Gooserider]

Thanks for the information. I was thinking about extending a pipe upwards, (higher than the highest radiator) from my overflow on the boiler, but am concerned about freezing.

Unless your boiler is designed to be operated as a closed system, that is not a good idea - open system boilers aren't designed to deal with that sort of raised pressure, so it could cause serious safety issues. Also quite likely is that the top of the boiler isn't terribly well sealed, and you would get leaks (the over flow is just intended to give you a "controlled" water path rather than running out the top and going all over the place...

Gooserider

 

[adcman]

Thanks all the help.