Hi all, thanks for reading,
We recently got a building of 4 stories and 4 1BR apartments on each floor.
The building has hot water heating using 3 peerless flex heat boilers (also supplying domestic hot water).
2" Water copper pipe comes out of those boilers to a ring, and from that ring goes out to the heating loop (1 1/4") that goes around the building and back to that same ring.
About a foot from when the heating loop starts, there's a circulator pump, Bell and Gossett.
In the months after last winter, the pump started leaking, and finally a few weeks ago it shorted the circuit so now it needs replacement. The exterior is all corroded so I can't see the exact model.
I had a plumber come in to replace the pump, and he offered me to get the pump myself if I can get it cheaper.
He gave me a part number. Before I ordered, I checked the specs and it was a 2 1/2" pump.
I asked him to confirm and he said, yes it's the part number he was given so I should get it. So I got it.
This is the pump corresponding to the part number he gave me:https://www.supplyhouse.com/Bell-Gossett-102218-1-4-HP-2-1-2-Circulator-Pump-5604000-p
Now the plumber tells me it's the wrong pump etc because he doesn't know if it would cause issues on a 2" size pipe on one side and 1 1/4" loop on the other side, and he doesn't know where to get 2 1/2" fittings, and and and..
I asked him why he gave me that part number, he said he described the building to his supply house and they looked it up on some chart and that's the pump they gave him for a certain head pressure.
I researched online and this is a pump that has a 2" connection:https://www.supplyhouse.com/Bell-Gossett-102214-1-6-HP-2-NFI-Circulator-Pump-5603000-p
Given 2" pipe on the supply side of the pump and 1 1/4" on the closed heating loop, and these 3 boilers etc.
And assuming the right fittings can be bought etc, will the 2 1/2" pump improve anything in getting good heat throughout the loop (without causing problems)?
Or should we go for the 2" pump, same model that was there before because that's the "safest" option?
Would greatly appreciate your advice, thank you