To get email notification when someone adds to a thread you're following, click on the star in the thread's header and it will turn yellow; click again to turn it off. To edit your profile, click on the gear.
The Wall has a powerful search engine that will go all the way back to 2002. Use "quotation marks" around multiple-word searches. RIGHT-CLICK on the results and choose Open Link In New Window so you'll be able to get back to your results. Happy searching!
In fairness to all, we don't discuss pricing on the Wall. Thanks for your cooperation.
mod-con boiler as back up
I am looking at using an OWB to heat a 20-30 gallon buffer tank through a heat exchanger. The buffer tank will feed the radiant floor pex system. When the OWB is off, I want to use a mod con on-demand propane boiler to take over in a re-circulating loop with the 30 gal buffer tank and the radiant system:. (6 loops of 1/2 inch pex each 250 feet long)
A Quietside 120 ODW mod con can accept input water as high as 120 degrees but requires at least 29 psi input at peak demand. A Taco-9 recirculation pump delivers 8 gpm at 34 feet of head and is recommended by Micheal Chandler in a similar system.
Question: Would this pump provide the 29 psi needed by the mod con?
Is there a formula that includes gpm, head, friction, pipe size....to calculate psi?
(From what I have read, mod-cons are generally not used in closed systems because of the pressure requirement)