Pumped mixer from Combi too hot

[RegPrescott]

I've just moved into a rented flat about a month ago and the shower is driving my girlfriend and I crazy.

It is a standard bath / shower mixer tap that seems to have both the hot and cold water being fed by a pump under the bath (both the cold and hot water taps will start the pump). The hot water is fed by a combi boiler that has not DHW temperature adjustment and the cold I assume is mains fed as there is no tank. Cold water pressure to the basin is a little low I must say.

Trying to balance the temperature of the shower is like trying to crack a safe! The hot water overpowers the cold quite easily and the temperature becomes scalding.

There's nothing I can do directly as the flat is rented but is there a device that I can recommend to the landlord that could be fitted to better balance the temperatures? Maybe there's a way to adjust the flow rates at the pump?

Any ideas would me much appreciated! We're going mad!!

 

[ChrisR]

Are you absolutely sure it's a combi - can you find a name/ model number on it?

If so...
Well, you wouldn't normally put a pump on a combi - unless it's fed from a tank.
If that's the case, all should be fine as long as the cold is also fed from the pump.

If your combi is mains fed, then pumped, that's illegal! But it could give you what you have.

If the pressures at the mixer are totally unbalanced, the hot will stop the cold, which seems to be what's happening.

Sounds like it could be a total mess.

Totally half-ar5ed workarounds which might get you a shower might be to turn a hot tap on elsewhere, to lower the pressure so the mixer stands a chance, or turn down the flow into the combi - there will be a spanner/screwdriver operated valve on its cold water input.


It's also possible your mixer supplies are backwards - should be hot on the left.

 

[RegPrescott]

Hi Chris

Sorry this took a while but just wanted to say thanks.

From what you say then the installation is indeed illegal having a mains fed combi and a pump fitted before the shower.

If it was my place I'd flip but as it's rented I'll continue to regulate the shower temp with the flow rate of the basin hot tap until next year

Thanks again.