PONPC question

Andy_14

You want the fill valve, expansion tank piped into the bottom of the air separator on the supply side pumping away from the boiler, before the circ. if that makes any sence

When pumping into the boiler you raise the systems pressure and chance popping the reilef valve

Unknown

We just started a big job

using P/S piping . We are piping almost exactly like this diagram shows ( from a post JohnNY started , I hope you don't mind buddy ) . The only difference is the primary circulator will be pumping across the flow of the system , not with the flow .

To the left side of the boiler connections we installed an air separator . This is where I want to pipe in the expansion tank . Will the primary circulator have any effect with regards to the PONPC ?

Thanks in advance , Ron .

rumn8r

Possibly...

All pumps SHOULD pump away from the PONPC. As it pertains to the boiler pump, it would be pumping TOWARD the PONPC, which means it would present its pressure differential as a drop in pressure through the boiler. Not a good idea on high pressure drop/high temperature applications.

Provided that you are not dealing with the need for a high residual operating pressure due to elevation, if it were me, I'd put the boiler pump on the boiler return or inlet, pumping AWAY from the PONPC, but towards the boiler.

I don't know if you remember the "conversation" we had a few weeks ago on this Ron, and the only thing I think we determined is that there really is no industry wide concensus on which pump is considered the "primary" pump, but my suggestion was that the pump, or pumps pumping away from the air seperator and the PONPC would be considered the primary pump, or pumps in your case, and then any heat sources would be a secondary heat INPUT connections.

Just my $0.02 worth on the subject.

ME