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Is my circulator undersized?
On Christmas day my boiler pump started making a terrible racket.
Turned out it was a failed coupler on my B&G Series 100 NFI.
I had a spare pump, a B&G NRF-22 that came with the new boiler I installed in 2010, and that I had set aside for just this situation.
This new NRF-22 pump seems to be doing fine, but is it a good fit for my needs?
On paper this pump might be undersized for my converted gravity system.
My system has three zones (one pump, three zone valves):
Zone1 - EDR=112.2 GPM=2.7 (first floor FR and kitchen)
Zone2 - EDR=299.6 GPM=7.5 (first floor LR, DR, Foyer, finished basement)
Zone3 - EDR=496.2 GPM=11.6 (second and third floor, 8 rooms)
Total - EDR=908.2 GPM=21.3
EDR was calculated by adding the values for all the radiators in my system.
The GPM values are extrapolated from a table posted in a previous Wall post:
According to this post, the NRF-22 has these maximum values:
NRF-22: GPM=17 EDR=725
Thing is, the system load depends on which zones are calling for heat.
Should I move up to a higher capacity pump like the B&G NRF-33?
Or are there better choices out there?
The NRF-22 does sound like a cheap timer.