Central heating Pump size

[darren bastin]

Hi, would anyone offer advice to the correct central heating pump size for a new boiler fit. I am looking to fit a Keston 55kw heat only boiler to replace an old Kingfisher floor standing boiler. The connections are 1 1/4 on the keston , the property is a three storey substantial place, with a few layers of extensions over the years, about 30 rads.

 

[Sharp Point]

Its not as easy as that, they're are lots of factors to put into consideration. Don't take this as gospel but the pump size is calculated to the index circuit and to do that you'll need to map out the system, measuring all pipe runs and determine there size, the number and type of fitting/s used.
Once you have all the details, you can then cross reference your readings to the pump curve and that will give you its suitability.

 

[stani]

Or, ring Grundfos on Monday and ask them, they are pretty good and on the ball with pump sizing.

 

[Sharp Point]

Or, ring Grundfos on Monday and ask them, they are pretty good and on the ball with pump sizing.

Thats cheating :tounge_smile:

 

[stani]

Of course it is! Lol

 

[darren bastin]

I think the local Grundfos rep is a good idea. Calculating pipe runs, sizes and fittings is a bit difficult in a top notch country house, cant really dig the concrete floors up and take a gander. There must be a rule of thumb given the heat input and number of rads.I think a 15/60 pump can handle 35kw for instancem

 

[AWheating]

What sized pump is currently fitted? does it work well?