shower pump problem

[jamesr36]

Hello. I installed a salamander rsp75 2.2bar shower pump to my last house. It is a conventional gravity feed system. HWC & bathroom on first floor. Cold tank in the loft. Pump only feeding the shower/bath. Rather than take the house to pieces I just put the pump under the bath on the original bath plumbing - ie not a dedicated feed. All worked great except the pump used to sometimes quickly switch on and off when I wasn't using it, sometimes repeatedly and normally when I turned on the basin tap (basin not connected to the pump). I assume it was caused by a pressure change triggering the flow switch in the pump. About to do a new install in my new house and want to make sure I dont have same problem. What do I need to do differently.

Thanks in advance.

 

[BournemouthPlumber]

You installed it completely against Salamanders (& Water Regs!) guidelines - and as such it wouldn't be covered by their warranty - and you are correct in your assumption that when another tap is switched on the flow is reduced such that it might turn off the flow switch on the pump until normal pressure is resumed.

You need to install dedicated hot and cold feeds to the pump from the DHWC and CWSC in 22mm pipe - and then 15mm pipework to the shower from there. You need to make sure that your feed to the pump from the CWSC is installed in the CWSC lower than the feed from the CWSC to the DHWC. This will ensure that if there is any issue with the water level in the CWSC it will be the hot water that runs out first rather than the cold - i.e. no chance of scalding whoever is having a shower. Not such an issue with a thermostatic shower, but should still be installed this way as good practice!

It is usual to install a pump in the airing cupboard as its much easier to pick up the hot and cold feeds from the tank - and then you can take the 15mm pipes to the shower up into the loft and drop down from there for the shower.

 

[jamesr36]

Thanks for your quick reply. I did read the guidelines but foolishly decided to ignore them to avoid taking the floors up in my newly decorated house. My new house is in pieces anyway so I will make sure its done properly this time.

I plan to use a sussex flange on the HWC with a dedicated supply from there. Since the connection of the dedicated supply and the rest of the hot water supplies come off the same fitting on the HWC is there still a risk of my old problem?

Thanks.

 

[MIGEM]

BournemouthPlumber is spot on.
Salamander do there own flange too, as it happens, for about £25.

 

[BournemouthPlumber]

I plan to use a sussex flange on the HWC with a dedicated supply from there. Since the connection of the dedicated supply and the rest of the hot water supplies come off the same fitting on the HWC is there still a risk of my old problem?

Thanks.

No, it will be fine as they are on different draw off pipes straight from the cylinder.

 

[jamesr36]

Thanks for the advice.