Grundfos 3 bar pump - pipe size?
Discussion
Upgrading my Wasp50 shower pump to a Grundfos 3 bar. It arrived yesterday and rather than just do a swap, thought I'd RTFM first.
That tells me that pipe to and from the pump should be in 22mm. Existing pipes are 15mm to about 50cm from the pump when they go to 22mm. Asked the supplier if that's OK and they say they'll let me know within 48 hrs but I wanted to do the job over the weekend and Grundfos don't have any humans there to give an answer, their Chat just says RTFM.
Do you think the existing set up will be OK?
That tells me that pipe to and from the pump should be in 22mm. Existing pipes are 15mm to about 50cm from the pump when they go to 22mm. Asked the supplier if that's OK and they say they'll let me know within 48 hrs but I wanted to do the job over the weekend and Grundfos don't have any humans there to give an answer, their Chat just says RTFM.
Do you think the existing set up will be OK?
Depends what you think is 'OK'.
If the new pump is more powerful than the old, it will probably deliver more water.
To deliver the most water possible, you'd fit minimal length pipes with no bends and definitely no right angle elbow fittings.
I'd say it would be OK, but I'm not mad about showers that empty a hot water tank in the shortest possible time.
If the new pump is more powerful than the old, it will probably deliver more water.
To deliver the most water possible, you'd fit minimal length pipes with no bends and definitely no right angle elbow fittings.
I'd say it would be OK, but I'm not mad about showers that empty a hot water tank in the shortest possible time.
OutInTheShed said:
Depends what you think is 'OK'.
If the new pump is more powerful than the old, it will probably deliver more water.
To deliver the most water possible, you'd fit minimal length pipes with no bends and definitely no right angle elbow fittings.
I'd say it would be OK, but I'm not mad about showers that empty a hot water tank in the shortest possible time.
Absolutely nothing wrong with shower pumps.If the new pump is more powerful than the old, it will probably deliver more water.
To deliver the most water possible, you'd fit minimal length pipes with no bends and definitely no right angle elbow fittings.
I'd say it would be OK, but I'm not mad about showers that empty a hot water tank in the shortest possible time.
Anyway, it’s not ideal but the 15mm pipes should be fine as it’s highly unlikely you’ll be running the shower at full flow anyway.
Actually had a reply from Grundfos
As stated in the instructions, you must use 22mm for that specific pump. Using 15mm will cause problems."
Not sure if that tells me anything useful since it's obvious that ALL shower temp/flow bars are 15mm so am no further ahead. Think I'll try it as described in the original post
As stated in the instructions, you must use 22mm for that specific pump. Using 15mm will cause problems."
Not sure if that tells me anything useful since it's obvious that ALL shower temp/flow bars are 15mm so am no further ahead. Think I'll try it as described in the original post
ColinM50 said:
Actually had a reply from Grundfos
As stated in the instructions, you must use 22mm for that specific pump. Using 15mm will cause problems."
Not sure if that tells me anything useful since it's obvious that ALL shower temp/flow bars are 15mm so am no further ahead. Think I'll try it as described in the original post
I think you'll find lots of shower mixers are 3/4 BSP inlets?As stated in the instructions, you must use 22mm for that specific pump. Using 15mm will cause problems."
Not sure if that tells me anything useful since it's obvious that ALL shower temp/flow bars are 15mm so am no further ahead. Think I'll try it as described in the original post
Most are sold with crappy restrictive adaptors to 15mm though.
It's possible to go 22mm or 3/4 all the way, I did this on a previous house with a gravity system with no pump.
I think you'll be fine, there are various online calculators to look at the pressure drop due to the smaller pipes:
https://www.pressure-drop.com/Online-Calculator/dp...
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