Combi- hot water pressure

[Jamieadvice]

Hi

We have recently had a 35kw combi boiler installed in a 4 bed 2 bathroom property.

Since the combi boiler was installed we are getting slow hot water pressure affected shower and bath I wouldn’t say it is trickling but it is not a good pressure where you feel clean. The bath takes longer to fill up.

If someone uses water elsewhere whilst the shower is on the shower will lose water completely.

Can any fixes be applied to the boiler or pipework be applied to resolve these issues please and so we can have a decent shower ?

Thanks

 

[Deleted member 120897]

What was installed previously and were pressure and flow rate tests carried out? What make and model is the new combi?

 

[Jamieadvice]

What was installed previously and were pressure and flow rate tests carried out? What make and model is the new combi?

I believe it was a vented system - Worcester boiler - tank and there was also a pump to increase water pressure ( I asked the plumber if I would have less pressure with the combi and he advised no as the combi has a pump within it)

There was no pressure or flow tests

 

[Jamieadvice]

I believe it was a vented system - Worcester boiler - tank and there was also a pump to increase water pressure ( I asked the plumber if I would have less pressure with the combi and he advised no as the combi has a pump within it)

There was no pressure or flow tests

The make and model of the new combi is Valiant eco tec plus 835

 

[Deleted member 120897]

There was no pressure or flow tests

A big no-no. Should have been carried out unless you can tell by looking at the cold. How does the cold water seem? Fast?

I asked the plumber if I would have less pressure with the combi and he advised no as the combi has a pump within it

Plumber talking utter garbage, they have a pump inside, but it’s feck all to do with the delivery of hot water.

I believe it was a vented system - Worcester boiler - tank and there was also a pump to increase water pressure

Ok, so with a vented system the pipe size would have been larger (generally) an some the pump would have been better for the delivery of hot water. Unfortunately it sounds like you may have been mis-sold a combi boiler, especially in your property size.

 

[Jamieadvice]

A big no-no. Should have been carried out unless you can tell by looking at the cold. How does the cold water seem? Fast?

Plumber talking utter garbage, they have a pump inside, but it’s feck all to do with the delivery of hot water.

Ok, so with a vented system the pipe size would have been larger (generally) an some the pump would have been better for the delivery of hot water. Unfortunately it sounds like you may have been mis-sold a combi boiler, especially in your property size.

Ok not good news then

The cold water is a lot faster ( downstairs) i would say upstairs when I compare hot and cold on the bath tap they flow about the same

Is there anything that can be done at all to increase this ? Ie bigger pipe work or is it the case the boiler is not fit for purpose and cannot be resolved

Thanks

 

[Deleted member 120897]

You might be able to have a pump installed, but something I’ve never had to deal with so not 100% sure. I certainly wouldn’t be asking the plumber who installed your combi about it. However I would go back to the plumber and ask “why is it so slow?”.

 

[Jamieadvice]

Ok not good news then

The cold water is a lot faster ( downstairs) i would say upstairs when I compare hot and cold on the bath tap they flow about the same

Is there anything that can be done at all to increase this ? Ie bigger pipe work or is it the case the boiler is not fit for purpose and cannot be resolved

Thanks

Well I have just tested downstairs again I would say the cold water is faster that hot downst

You might be able to have a pump installed, but something I’ve never had to deal with so not 100% sure. I certainly wouldn’t be asking the plumber who installed your combi about it. However I would go back to the plumber and ask “why is it so slow?”.

ok thanks Chris

 

[ShaunCorbs]

Need to start with pressure and flow of the kitchen tap hot and cold

Also you won’t run two outlets of hot at the same time with a combi boiler

 

[Jamieadvice]

Need to start with pressure and flow of the kitchen tap hot and cold

Need to start with pressure and flow of the kitchen tap hot and cold

Also you won’t run two outlets of hot at the same time with a combi boiler

 

[Jamieadvice]

Hi Shaun

The pressure in the kitchen the cold water has more power compared to hot not sure where the plumber should be starting with that

 

[ShaunCorbs]

Would you say the hot pressure is roughly 3/4 of the cold in the kitchen?

 

[Jamieadvice]

Would you say the hot pressure is roughly 3/4 of the cold in the kitchen?

Yes that is the difference

 

[Jamieadvice]

Would you say the hot pressure is roughly 3/4 of the cold in the kitchen?

Yes that is correct

 

[ShaunCorbs]

Sorry to say that’s normal then hot being 3/4 the pressure of your cold due to having to go up and then back down etc

 

[Jamieadvice]

Sorry to say that’s normal then hot being 3/4 the pressure of your cold due to having to go up and then back down etc

S

Sorry to say that’s normal then hot being 3/4 the pressure of your cold due to having to go up and then back down etc

ok thanks my combi installed says that it should deliver 12L a minute I have done a test with a jug and it works out 3L a minute .. what would you advise please?

 

[ShaunCorbs]

Call the installer back

 

[ShaunCorbs]

It should come out at least 10 lpm