circulators, feed or return side?
mbmmd
| Posted in Energy, Heating & Insulation on
currently upgrading my fhw system. due to insufficient head pressure with current circ. taco 008, have been advised to change to 0011 model which seems reasonable to me. The question is feed or return side. Most of the installations (including mine) have the circulatior on the return loop but several HVAC guys have recommencded swapping to the feed side of the boiler for better performance. Any thoughts would be appreciated.
Replies
Everything I've ever read or heard calls for 'pumping away' from the boiler.
I've heard the same: pump away. I think this keeps air from accumulating in the rads/tubing, since it increases the water pressure there. The air separator should be between the boiler and the pump, as that's where the water is hottest, and at lowest pressure.Someone correct me if I'm wrong...
You want to pump away from the ponpc - point of no pressure change - the expansion tank. Typically, the expansion tank is attached to the air scoop. The point of lowest pressure and highest temp is the best place to remove air from the system.
So, the ideal setup is boiler, scoop/expansion tank, pump.
Will it work setup differently? Yes. But it will work best pumping away from the ponpc.
BTW, if you are using an automatic feeder, it should be tied in at the ponpc.
You beat me to it.
We must have been typing at almost the same time. ;-)
"Let's get crack-a-lackin" --- Adam Carolla
Yeah, but I like the possibilities you present better.
Somewhere over at the Wall, there was a formula for how much energy was created when you deadhead a pump. Even a small wet rotor has the potential to be spectacular.
Thanks everyone for the advise. Supply side it is! Now where did i put that torch?
Another vote for pump away.
The "ideal" is pipe boiler outlet to expansion tank/air separator to pump inlet to heat distribution piping back to boiler inlet. This will give you maximum pressure in your distribution piping with no pressure drop on the inlet side of the pump ("point of no pressure change" at the expansion tank so no pressure drop on the inlet side of pump. Modern pumps are designed for boiler outlet temp, so no problem there.
If you go with a different arrangement (like expansion tank on outlet side of pump) you can actually draw negative pressure on the inlet of the pump. Cavitation and good bye pump. Draw it low enough with a high head pump combined with high head loss in the distribution piping and low static pressure, you can get the pressure down a good bit subatmospheric, lower the boiling point of the fluid and, if it's hot enough, maybe good bye whoever is in the vicinity.
"Let's get crack-a-lackin" --- Adam Carolla