Luke Warm Water from Hot Tap

[tyzer007]

Hello - and thank you in advance for your help on this one.

We have a Salamander Homeboost pump fitted to the mains supply to our flat. We have tanked hot water which is heated by our Valliant Ecosystem 30KW boiler. The flat has 3 bathrooms upstairs, 1 downstairs and kitchen taps.

When the Homeboost pump is on, we check the temp coming from the tank (37C) and when we disconnect the hot tap from the kitchen mixer tap and check the temp it is 16C. The same is true for one of the upstairs bathrooms. The problem seems worse for the bathtub where there are dedicated hot and cold taps compared to the mixer tap for the shower.

When the pump is not turned on, the temperature in the kitchen and affected bathroom is Ok - but not as good as the hot temperature from the other 3 bathrooms.

We think that the issue may be a mixer tap that is allowing the hot and cold to intermingle. But we don't know how to trace this to identify for sure.

According to Thames Water we are in a Pressure Managed area which means our water pressure is fine daytime, but that in the evening Thames drops the pressure and then we need a boost.

Any help is diagnosing this problem is much appreciated. Thank you!

 

[Riley]

WhT sort of hot cylinder have you got. Any pics

 

[Burger]

Have you changed any of the taps recently? Had any work/modifications done recently?

 

[tyzer007]

WhT sort of hot cylinder have you got. Any pics

MegaFlow - CL210

We know that there is a flow balance valve attached. We initially thought it had failed so have replaced that - but with no change.

thank you!

 

[tyzer007]

Have you changed any of the taps recently? Had any work/modifications done recently?

We have had a new boiler installed (plumber who did the install came back - but was unable to diagnose the issue). We changed one of the upstairs shower mixer taps - professionally changed.

 

[Riley]

Unlikely to be related but no one in their right mind should’ve fitted a megaflow to 12litres a minute pumped incoming.

 

[Riley]

The only way to test is to isolate the cold on each mixer and see if it affects your problem

 

[tyzer007]

Unlikely to be related but no one in their right mind should’ve fitted a megaflow to 12litres a minute pumped incoming.

Thanks for this. Can you explain a bit more? We attached the HomeBoost pump to the mains so that there would be the same pressure going to both hot and cold.

 

[tyzer007]

The only way to test is to isolate the cold on each mixer and see if it affects your problem

Due to the nature of the fittings it is not possible to isolate. (Builder was not the best - always cutting corners.)

There are isolating valves in the kitchen - but nowhere else. Not even in the bathroom sinks. And due to the nature of the shower mixer valves, we can remove the cartridges - but can't actually shut them off.

I guess my question is: "Do you think the most likely situation is that one of the mixer valves is the culprit?" - Because if that is the case I think I can identify which one based on the way the pipes flow.

In other words - The cold and hot have already mixed by the time they get to the kitchen and there are only 2 taps between the tank and the kitchen.

Again - many thanks.

 

[Riley]

Thanks for this. Can you explain a bit more? We attached the HomeBoost pump to the mains so that there would be the same pressure going to both hot and cold.

The Homeboost pump would give you a maximum of 12lpm as water regs prevent them giving you more. On that basis I would never in a million years be fitting an unvented cylinder as the flow rate is not sufficient.