Shower Pump Pipework

[GSD]

We moved house a few months ago and inherited a Phoenix Wasp 60 shower pump. This was in a positive head situation with 15mm hot and cold feeds both to the pump and to the shower itself.

When we started to use this we quickly noticed that the hot feed to the shower often got quite badly airlocked which could take some time to clear. Eventually we found that we could alleviate this by running the hot tap to the bathroom sink for a few minutes first which allowed the air trapped at the top of the hot tank to be released.

Recently we decided that we didn't want to tolerate this any more and arranged for a plumber to instal a surrey flange on the top of the hot tank and to replace the hot feed to the pump with 22mm pipework. This works extremely well and makes showering pleasurable again but I'm just a bit concerned that the rest of the pipework to and from the pump is still
only 15mm. Does this matter?

Also I can find no reference to a Phoenix Wasp 60 pump on the web, albeit that it looks very much like a Millstream Wasp 46 or 66 pump which in turn seems to have been rebranded as the Grundfos Niagara pump which comes in either a 1.5 or 2 bar version. Just in case we ever have to replace our existing pump I would be very grateful for any guidance as to which pump would make a suitable replacement.

With many thanks, GSD

 

[LUNAT]

HI

there is no harm in 15mm pipes but it is better in 22mm.this will reduce extra load on the pump.

 

[ChrisR]

FIgures like 60 usually mean 60 feet head, which is just under 2 bar.
If the pump isn't cavitating the supply side is probably OK, and 15mm on the output will only reduce the flow a little. So it depends how long it is. Remember that in most showers the combined hot and cold together both go up the hose, which will be a lot less than 15mm internal diameter.