what is the best pump location supply or return on a boiler

Ron Schroeder

You might want to put in a call to Burnham or other manufactuer, depending on the model you are installing, Burnham might have a good reason for wanting the pump on the return. Sometimes generic questions do not fit every situation and then again they may have a beter answer than when that manuel was last updated.

Good Luck
Bruce

Oney

Pump Location

Which side of the boiler is best for locating my pump... Supply or Return?

Doug Bird

It really doesn't matter on which side of the boiler you locate the pump. What does matter, however, is the location of the EXPANSION TANK. The point of no pressure change. It's always best to locate the expansion tank on the SUCTION side of the pump. That makes sure you have adequate positive pressure throughout the system. This helps to avoid pump cavitation, flashing and air problems.

Brad White_115

Yes, and...

it also depends...

Many prefer that the air separator be located downstream of the boiler because the hotter the water the more air is released. The air separator often has a connection for the expansion tank hence it tends to go there out of convenience if nothing else. Ergo, the circulator goes downstream of that. For all the reasons Doug stated of course.

However, some boilers require the circulator to be on the inlet side to create the maximum positive pressure to activate the pressure switch which is part of the safety circuit. Typically these "pumped into" boilers have a secondary circuit in which the expansion tank and air separator would go, again, upstream of the secondary circulator.

Argie

circulator and expansion tank

I am preparing installing a new boiler (and have a certified hydronics professional do the checkout and startup). My existing hot water boiler-- 15+ yr. old Columbia boiler-- has the circulator on the return loop with the expansion tank and water feed regulator on the supply loop side. The new boiler-- Burnham cast-- has the circulator on the return side and the plumbing diagram calls for the expansion tank and water feed regulator to be on the return side as well. Is it not simply better to go with the manufacturer's installation guide so I don't void any warranty or run into a sticky situation when the professional comes in to start up the boiler?

EBEBRATT-Ed

As the other posts have mentioned you ALWAYS want to pump away from the expansion tank. True, on many "house jobs" you can probably get away with pumping toward the expansion tank due to the low resistance of the system however, all systems will work better if pumping away.


With regard to the pump location in relation to the boiler I personally like to pump away from the boiler. If you pump towards the boiler you could cause the relief valve to lift if the system has high resistance.


Ed