Grundfos UPS2: will 25-80 (180) head fit a 15 50/60 (130) body
- Thread starter hornulus
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- grundfos grundfos 15/60
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The impellors will also be different.
if you actually need a 25/80 then you will have to get another if you dont you can get pump extensions that will take up the gap , I doubt however if your installer would have put in a 25/80 if you didnt need it, you cant just swap the heads
Tnks.
My system (after two house extensions) has 22 radiators and two DHW cylinders. It is 40 years old in places and has run a UPS2 15 50/60 (130) and its predecessors since it was installed. The Thorn M56/76 21KW boiler gave sterling service but was clearly struggling (and kettling) badly in the winter. It was recently replaced by a 35KW Viessmann Viotodens 100W open vent after sizing in detail using Stelrad's STARS app.
The boiler is now cycling every few minutes and, watching the outflow temperature on its display, hits the 60C to 65C upper limit quickly after it cuts in, which seems to suggest that it cannot dissipate its heat fast enough through the radiators. Even so, the radiators seem to take a long time to warm up, although around ten or so are on low TRV settings.
With the boiler on its highest temperature setting, if I set the UPS2 50/60 to proportional pressure (which appears to be the correct setting for a system with lots of TRVs) instead of constant speed, the system is reluctant to heat at all!
Hence my looking at the 25/80. But there is no latitude in the pipework for a 50mm wider port-to-port distance, and cutting a section out will be awkward because of bends and joints.
My system (after two house extensions) has 22 radiators and two DHW cylinders. It is 40 years old in places and has run a UPS2 15 50/60 (130) and its predecessors since it was installed. The Thorn M56/76 21KW boiler gave sterling service but was clearly struggling (and kettling) badly in the winter. It was recently replaced by a 35KW Viessmann Viotodens 100W open vent after sizing in detail using Stelrad's STARS app.
The boiler is now cycling every few minutes and, watching the outflow temperature on its display, hits the 60C to 65C upper limit quickly after it cuts in, which seems to suggest that it cannot dissipate its heat fast enough through the radiators. Even so, the radiators seem to take a long time to warm up, although around ten or so are on low TRV settings.
With the boiler on its highest temperature setting, if I set the UPS2 50/60 to proportional pressure (which appears to be the correct setting for a system with lots of TRVs) instead of constant speed, the system is reluctant to heat at all!
Hence my looking at the 25/80. But there is no latitude in the pipework for a 50mm wider port-to-port distance, and cutting a section out will be awkward because of bends and joints.
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sorry I read this post the other way, I thought you had a 25/80 and were looking to replace it with a 15/60, no you cant do it by just replacing the heads , as Dan said the impellors are different complete new pump required if you want to increase the pump performance
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