A shower too far?

[Neil2010]

HI there
I have a problem with low (no) pressure in the two ensuites I have put in my extension. These are some distance from the hot / cold water tanks as the extension is built over the garage, so it is probably about 10- 15 metrre pipe run for both hot and cold.
Each shower has a gravity fed pumped thermostatic shower (I know i should have fitted one lectric shower but my daughter pulled her face and wanted the same as her brother - girls!!).
The problem is that even with just the one shower running, there is no pressure to the hot water tap in the mixer tap in the adjacent sink. When Shower 1 (which is upstream on the hot water pipe) runs, it seems to cause the shower 2 hot water to 'suck back' and that means there is a risk that shower 2 pump will run dry. I know about high pressure hydraulics because I was an aircraft engineer for 14 years, but I'm not so certain about domestic LP water - do the same rules apply?
My question is - can I somehow

• fit non-return valves to stop the 'suck back'?
• bleed of a limited amount of pressure from upstream of the pumps back to the downstream side to maintain integrity of the water supply to the other pump, and stop the lack of pressure to the taps?

Just to make things complicated, the hot ater is upstream on Pump 1 and the cold water is upstream on Pump 2 (because of the way the existing hot water was routed, and the way I had to route the cold water through the loft.)

There must be a brilliant mind out there that has all the answers
Neil

 

[WHPES]

Your problem is due to the showers being incorrectly plumbed in. None of your suggestions will work. The only way to do it is to plumb it in properly.

Showers must have their own independent supplies. For each shower, for the hot supplies fit an independend outlet from your cylinder using Surrey flanges, and for the cold supplies take two independent cold feeds directly from the DHW header tank. This will cure the problem.

Alternatively you can have a single 22mm supply from the tank and the cylinder to one larger pump suitable for multiple shower installations, and then split it off to the two showers afterwards.

 

[Plumbstar Tom]

Yep they are starving each other

Pumped products should be fitted on independant supplies

SO re plumbing is required and I would recommend the use of Essex flanges

 

[Neil2010]

Gents, thanks for your replies . looks like the carpet is going to have to come up again....

 

[Blackcatgas]

The Salamander pump website has some good technical drawings and advice,.