Salamander Homeboost, Hot water coming out of cold tap

[David Medlycott]

Hello

I have a Vaillant Ecotec Plus 835 with a Salamander Homeboost pump fitted to the mains supply underneath the boiler.

If I switch on the cold tap first I get cold and if I switch on the hot I get hot, the booster kicks in but doesn’t switch off, but..

If I switch on the hot tap first the booster fires; does not switch off when I close the tap, then if I open the cold tap hot water flows?

If I close one of the isolation valves the pump stops as expected, and if I switch the pump off completely the taps work correctly.

My gas engineer says it’s bizarre and can only suggest replacing the pump, Salamander say they don’t think there is anything wrong with the pump as it stops when the isolation valve is turned. And neither can understand why hot would come out of the cold!?

Any suggestions would be appreciated!

Thank you
David

 

[New Gas Engineer]

"If I close one of the isolation valves the pump stops as expected, and if I switch the pump off completely the taps work correctly."

With this info, Id say try changing the pump.

 

[Riley]

Get salamander in if they’re sure nothings wrong

 

[David Medlycott]

Get salamander in if they’re sure nothings wrong

Out of warranty

 

[Riley]

They will still offer a repair service

 

[ShaunCorbs]

@SalamanderPumps any help ?

 

[Aire]

Id agree with salamander on this one. If the pump stops when isolated, that proves the pumps flow/pressure switches work.

Where in relation to the stop tap is the home boost fitted?

I'd also be asking your installer why he's fitted an 835 which is capable of 14ltm of hot water delivery, when the home boost is restricted to 12ltm.

 

[David Medlycott]

Id agree with salamander on this one. If the pump stops when isolated, that proves the pumps flow/pressure switches work.

Where in relation to the stop tap is the home boost fitted?

I'd also be asking your installer why he's fitted an 835 which is capable of 14ltm of hot water delivery, when the home boost is restricted to 12ltm.

 

[David Medlycott]

Someone has suggested that maybe one of my mixer taps or shower thermostatic controls could be worn and allowing cold into the hot so when the hot is switched off cold could still be sleeping through..?

 

[David Medlycott]

Id agree with salamander on this one. If the pump stops when isolated, that proves the pumps flow/pressure switches work.

Where in relation to the stop tap is the home boost fitted?

I'd also be asking your installer why he's fitted an 835 which is capable of 14ltm of hot water delivery, when the home boost is restricted to 12ltm.

The booster is fitted 1m below the isolation valve and boiler.

Ground floor kitchen tap doesn’t get as hot as 2nd Floor bathroom?

The pump is fitted because my 3rd floor shower struggles with pressure, Ground Floor is adequate.