2nd circulator pump with flow switch

[mrbugs]

Could anyone offer advice
I have a Y plan vented system, in a chalet bungalow.
After an extension the current pipe run is long / pump struggles to get how water downstairs, however upstairs (due to shorter, easier pipe runs gets hot)
So I am thinking a secondary heating circulating pump with inbuilt flow swich, this will be fitted to downstairs flow, (Wiring will be independent... otherwise would interfer with Y plan system).
or is there a better way of increasing flow to downstairs? (16 rads total, long pipe runs and the downstairs heating water has to travel back to 1st floor before returning to boiler on ground floor).
(Balancing the rads doesnt quite work.)
thanks for any pump / flow switch advice recomendations

 

[Johntheo5]

What is the make/model of your existing pump and what setting is it on?, you just need the existing pump head removed and impeller and ports cleaned or a new higher head pump
You could, even though not generally recommended, install another circ pump like my Wilo Yonos Pico where you can set the pump head very low if required to give the required boost, you may be able to take a supply from the programmer to just start this pump when CH is required, do you allways run the upstairs/downstairs together?.

 

[mrbugs]

hi, thanks for the reply,
I have a

GRUNDFOS 98334549 UPS2 15-50/60 PUMP​

runs on max, it has been cleaned.

perhaps not powerful enough then...

I see the problem as being that downstairs has twice the volume to heat (chalet bungalow) , the boiler (ground floor) has the water pumped up to 1st floor (pump and water cylinder), then split into 2 x 22m pipes, one for upstairs, one for down. The downstairs water then has to flow back to 1st floor before returning back down to the boiler (this is how the system has been laid).
So upstairs has easy circulating / no restriction problems, ( has easy flow and return). Downstairs has much longer pipe run and much higher heating BTU requirements (bigger rads), and has to contend with the extra level.

 

[Johntheo5]

hi, thanks for the reply,
I have a

GRUNDFOS 98334549 UPS2 15-50/60 PUMP​

runs on max, it has been cleaned.

perhaps not powerful enough then...

I see the problem as being that downstairs has twice the volume to heat (chalet bungalow) , the boiler (ground floor) has the water pumped up to 1st floor (pump and water cylinder), then split into 2 x 22m pipes, one for upstairs, one for down. The downstairs water then has to flow back to 1st floor before returning back down to the boiler (this is how the system has been laid).
So upstairs has easy circulating / no restriction problems, ( has easy flow and return). Downstairs has much longer pipe run and much higher heating BTU requirements (bigger rads), and has to contend with the extra level.

If one assumes a total rad demand of 30kw, then these will require a circ flow of 28.7LPM, 1.72ms/hr, at @ 15C dT, the UPS2 will circulate this vol of water at a 3.7M head but a UPS3 will circulate it with a head of 5.0M, a 5M head is pretty good and the UPS3 may be
worth a punt??

 

[DontHurtTheNoob]

Before upgrading the pumps I would make sure the system is balanced. Even if the upgraded pump could push water through the more restrictive downstairs radiator circuit, it will still "prefer" the less restrictive circuit so if will make little to no difference if the system is not balanced.

The procedure is in the FAQs here

In theory if you have thermostatic radiator valves on every radiator they will adjust - when the upstairs warms up they will close more and more and this will result in more water taking the downstairs route, but they will be last to get warm and it can take a while. If you don't have TRVs, (a) get some and (b) balance the system anyway.