New bathroom plumbing

[Richard C]

I am installing a new bathroom with shower bath & will be running new H/C feed lines for a power shower from a 2 bar pump - we intend installing another en-suite shower at a later date. The house is mid 60’s & I’m pretty certain it hasn’t been touched since & so I am unsure about condition of existing plumbing. Rather than replace the bath sink runs separately, is it acceptable to tee off the pumped H/C shower runs to feed the bath & basin unit?

 

[Softus]

Yes; however, it's prudent to install a bypass so that when running a single outlet (like a hot tap) from a twin pump the water from the 'idle' impeller has somewhere to go.

I've heard on the grapevine that Stuart Turner have started recommending this - I haven't asked them yet, but I know that last summer when I consulted them over a neg. head pump that they made no mention of it then.

 

[ChrisR]

They (ST etc) will give you a time which is OK for running into a closed end, typically enough to fill say a basin with water from one tap. The danger is that the pump overheats, which takes a while. If you like 15 minute cold showers there could be an issue.

 

[Richard C]

Yes; however, it's prudent to install a bypass so that when running a single outlet (like a hot tap) from a twin pump the water from the 'idle' impeller has somewhere to go.

Must confess I never thought of that! How do I provide a bypass loop, is it just a connection across each pump inlet & outlet? Won’t this prevent the pump flow switch operating? I notice that the Salamander RHP 75 has a built in bypass loop, is this worth considering?

 

[Nige F]

you can buy a retro fit bypass from Techflow pumps in Burgess Hill..in god`s own county

 

[Richard C]

Thanks; I thought all shower pumps had 22mm inlet/outlet but have noticed there are some 15mm ones around. 15mm pipework is obviously a lot easier & cheaper to install but I wouldn't like to compromise the shower performance & obviously the flow rate is lower for a given pressure but as most mixer valves reduce the line to 15mm or less anyway, does the smaller pipe make any difference in reality?