BTU Pex Questions

[bowhuntr311]

Hey all,

Its been a while since I been here but I know someone here will be able to answer this.

My coworker has a situation.

Outdoor wood boiler coming into his home into his utility room (1inch pex open loop). From the utility room to the garage he has a 60 foot loop of 1/2inch pex. He wants to hang a modine style 50K btu water/air exchanger and is concerned about not enough volume to use the heater sufficiently. He's up in the air if he will do a closed loop system on a zone controller or T into his open loop supply line. His stove temp is in the 165-175 range.

Anyone have any layman term input.

Thanks.

 

[HoosierBuddy]

Well...I have no idea other than what I just learned on a google search. It shows that unit heater has a 1-1/4" inlet and a 1-1/4" outlet. I'm going to say "No". But...to know for sure you'd have to be able to calculate the amount of water that would be flowing through the unit. Seems like you'd have to know the pressure of the loop, available pumping capacity...that sort of thing to calculate with any confidence.

Phil

 

[fitter30]

1" pex flows 10.4 gpm @4 ' per second. Need to know what pump does he have, does the 1" just feed the 60' of 1/2"and brand and model of heater? Is the 1/2" pex in slab or under floor?

 

[Sokoloff]

50K BTU/hr at a delta-T of 20ºF means 5 gpm of water flow. In 1/2" Pex, that would require 17 psi of pressure drop over a 60 foot run. That's about 40' of head, which is too much, IMO.

You're more likely to get 1-2 gpm of water flow, or 10-20K BTU/hr.

I'd run new Pex.

 

[bowhuntr311]

Thanks for the input. I knew someone could make simple sense of it for me.

 

[fitter30]

Need to know model and brand of pump to see if the pump will work.