CH pump replacement concerns.

[John.g]

Let us know how you finally get on.

 

[diydave]

Let us know how you finally get on.

Old pump has gone quite quiet since it learned it was going in the bin!! Waiting Boiler Service Engineer's advice coming soon and Dab Evosta2 or 3 will be ordered thereafter as required.
Thanks again for help.

 

[diydave]

Eventually went for Evosta 3 'cos a well known online supplier had a bargain on his Ebay shop! Running like a dream with good flow/return temp diff throughout using Proportional 3.

 

[John.g]

What is the pump power output and flowrate with those 19 rads?? Is it a 8M pump?

 

[diydave]

6m pump John. I'm running it at Proportional 3. 34W 4.2m head 3.3cu m per hour initially. Will monitor it more closely after I've rebalanced the rads. 13 of the rads have thermostatc valves so I expect to see differences as house warms up.

 

[John.g]

I interpret from the pump curves that the flowrate is 1.02m3/hr, 17.0LPM which, depending on the rads output may give a dT of 15C to 20C.

 

[John.g]

 

[diydave]

Apologies John. Typo on my part. Indicated flow rate is indeed 1.3 cu m per hour and your delta T of between 15 to 20 deg C across the boiler is spot on. Delta T across radiators is very variable because of thermostatic valves. Delta T across boiler drops when hot water cylinder calls.