Trial removal of second CH pump

[Max]

Been renovating my house and in the process improved insulation and removed quite a few rads. I've also installed more than half downstairs floor with underfloor heating which has it's own manifold with attached pump (UPS2) as supplied by the underfloor heating supplier.

Boiler is sited remotely in outbuilding with the main pump, Grundfos UPS 25-55 180. About 25m run of 35mm pipe to house under tarmac then comes up through floor inside and then initially into 28mm pipework and what I think is now a possibly unnecessary second pump, Grundfos UPS 15-50 130 which is set to lowest speed (1 of 3). 22mm copper circulates round house to rads.)

Now I've removed several rads, zoned system up/down/underfloor (total now of 10 rads + 4 towel rails) I'd like to trial the system with just the one boiler pump and bypass the internal house pump, but rather than draining down the whole system I'd like to trial it first to make sure it proves adequate.

Are there connectors available that match those on the pump so I can just close off the valves either side and replace pump with matching pump connectors and straight pipe, temporarily in case I am wrong and end up putting the pump back? Had a quick Google but don't see what I would need to do the quick swap-out? Other than that it's full drain down and take out the pump connectors and back to compression joints that are either side of the pump shut-off valves, but prefer to avoid if possible just for a quick trial.

Thanks for looking.

 

[John.g]

You could do a quick trial right now with it switched off as the pressure loss through the stopped pump will be very little, you will get a feel for it right away if any problems.

 

[Max]

Thanks John. I did think of that but then assumed the pump might offer too much resistance. Does it depend on pump make/design or are all pumps pretty good through-flow when switched off?

 

[John.g]

All much of a much, (pretty good) centrifugal pumps, the stopped pump only builds up resistance if its impeller and ports are sludged up.

Even though you have replaced?? half downstairs with UFH which has its own manifold pump you will still be supplying this pump with some water from the main UPS 25-55 180 depending on boiler flow/UFH manifold temperature differential so allow maybe 30 to 50% of original flow rate for this area when carrying out tests and carry them out with UFH requesting heat as well. If looking good then you can remove (or not) the UPS 15-50 130.