Any plumbing experts ?

[RogerS]

Thanks, E.

I'd better not start on Matki !

 

[nolly47]

Hi Roger
I assume that the cold-water pump is flow and pressure operated so cold-water pipework is always at 1 bar even if nothing is turned on
You don’t have a secondary return back to the hot water cylinder, do you?
When the pumps was running after the shower was shut off did you check the overflows from the loft and break tanks?
With the on suite isolated now, is the hot water and hot water pump working with no problems?
Steve

 

[RogerS]

Hi Roger
I assume that the cold-water pump is flow and pressure operated so cold-water pipework is always at 1 bar even if nothing is turned on

Yes. And the hot water system is also pressurised at 3 Bar as that's the pump rating.

You don’t have a secondary return back to the hot water cylinder, do you?

Sadly no. Should have put one in.

When the pumps was running after the shower was shut off did you check the overflows from the loft and break tanks?

I see where you're coming from but no.

With the on suite isolated now, is the hot water and hot water pump working with no problems?
Steve

Still waiting for the parts to arrive from Hans Grohe.

 

[nolly47]

Hi Roger
At the present moment have you got the pump running with just the on suite isolated with the valves shown on you first drawing?
H/W pump stops. Then after ten seconds or so, starts up for a little bit then stops.
1 .This is happening I think because there is no nonreturn valve on the hot water by the pump and what is happening is that when the pump in on there is 42lbs of pressure on the pressure side and 4lbs on the low pressure side when the pump goes off the high pressure side backs up the low pressure side least line of resistance up the expansion pipe this now means that the low pressure side has more pressure than the high pressure side so forces itself through the flow switch energizing the pump when pressure is back up on pressure side pump shuts off and it starts all over again.
2 . As for the shower valve and the non return valves I would put the shower valve back together switch off the hot water pump electrically turn on the water to the cold side check for leaks then turn on the hot side and again check for leaks, then turn on hot water pump then turn on one of the hot water tap in another bathroom or kitchen to bring the pump on then turn tap off, see if pump turns off, if it does except for the bit at top of page that’s OK then turn hot water tap on just enough to make the pump run this with at least test every things under pressure
3 . make certain that all the plumbing cisterns tanks etc are full of water If the pump runs continually switch shower off and pump electrically, then it a two-person job turn pump on one person to turn on the shower on, one in the loft to see if tank is filling with water from the water main, if it is then check the break tank and any other overflows.
Steve

 

[RogerS]

Hi Steve

All now working after fitting those non-return valves in the HG shower controller - that were omitted at manufacture.

Thanks for all your suggestions.

 

[1steven]

Had similar with a customer, took out the pumps and fitted an unvented cylinder. He loved it no more noise plus exel pressure all round.