Boiler dhw flow adjustment

[Minidriver]

Hi guys. New here.

Basically I bought this house 2 yrs ago. Back when I bought it I took over an existing plan with British gas for my boiler servicing.

Upon first service, I asked about hot water as if you turned the bath tap on more than 1/4 turn it ran like warm at best.

He said he adjusted the flow down and it worked better. He seemed to adjust a valve in the boiler or below it, couldn't quite see. He checked with a measuring device and timed it and all was well.

Roll on 2yrs ish, I've been sorting issues around the house. Including banging pipes, turns out I had 8bar incoming from the street.

So I've fitted a prv after the stopcock set at 3bar. Loads better, no banging pipes when taps are shut or washer fills etc.

However this seems to have made the hot water tap run slow and it's not red hot either. Its hot but you can bare to keep your hand under it and it's set on 65c according to boiler.

I don't know if the boiler works harder if the flow is faster or not. But I would like to increase the flow speed.

Currently its like when the tap is on fully open, it's comparable to 1/4 open previously. If that makes sense.

The boiler is a worcester greenstar 26i if I recall correctly. Any advice where the flow adjustment is? Is it an actual adjustment for the dhw or did he just close the valve letting the cold feed into the boiler?

Thanks for the help
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I tested hot water at kitchen sink and bath and it's approx 14secs a litre. So 4.5 litre per min? That's fully open tap and no other taps or water usage going on.

 

[SJB060685]

Adjusting the flow rate through the DHW PEX is possible by a couple of ways. I suspect hes just closed the inlet valve slight, although he could have done it inside the boiler. You need to get a GSR out, you cant do this yourself

 

[Minidriver]

I will wait till next service and ask them to test it and adjust it as required.

At least the cold water mains is now at 3bar and my house isn't banging every time washer fills and stops. Haha.

Cheers for the reply

 

[SimonG]

Think that boiler is only 10 litres per minute so your flogging a dead horse.

See it all the time with combi swaps on the bath tap. So much so I fit a valve on the bath hot to reduce how much water it can run.

 

[Minidriver]

Think that boiler is only 10 litres per minute so your flogging a dead horse.

See it all the time with combi swaps on the bath tap. So much so I fit a valve on the bath hot to reduce how much water it can run.

10 is double the 4.5 I am getting though?

Plus it was running faster when the mains pressure was 8bar, so knocking it down to 3bar must have made some difference.

I'll get it checked when it's next serviced.

Cheers

 

[John.g]

Hi guys. New here.

Basically I bought this house 2 yrs ago. Back when I bought it I took over an existing plan with British gas for my boiler servicing.

Upon first service, I asked about hot water as if you turned the bath tap on more than 1/4 turn it ran like warm at best.

He said he adjusted the flow down and it worked better. He seemed to adjust a valve in the boiler or below it, couldn't quite see. He checked with a measuring device and timed it and all was well.

Roll on 2yrs ish, I've been sorting issues around the house. Including banging pipes, turns out I had 8bar incoming from the street.

So I've fitted a prv after the stopcock set at 3bar. Loads better, no banging pipes when taps are shut or washer fills etc.

However this seems to have made the hot water tap run slow and it's not red hot either. Its hot but you can bare to keep your hand under it and it's set on 65c according to boiler.

I don't know if the boiler works harder if the flow is faster or not. But I would like to increase the flow speed.

Currently its like when the tap is on fully open, it's comparable to 1/4 open previously. If that makes sense.

The boiler is a worcester greenstar 26i if I recall correctly. Any advice where the flow adjustment is? Is it an actual adjustment for the dhw or did he just close the valve letting the cold feed into the boiler?

Thanks for the help
[automerge]1583083748[/automerge]
I tested hot water at kitchen sink and bath and it's approx 14secs a litre. So 4.5 litre per min? That's fully open tap and no other taps or water usage going on.

That boiler should supply ~ 6.8 LPM at 65C or ~ 10.5 LPM at 45C (from cold at 10C) so it should have no problem in supplying hot water at 4.5 LPM, its possible I suppose but unlikely that the flow switch (probably set to ~ 3 LPM minimum flow) is faulty and starting/stopping the burner but you should be able to hear this if you stand near the boiler.
Based on your flow of 4.5 LPM @ 3 bar would indicate that your plumber had adjusted it to give ~ 7.5 LPM at the original pressure of 8bar.
This reduced pressure is also the reason why you have to open the tap fully now vs 1/4 turn previously.
Possibly also fault may be with the boiler heat exchanger so as advised above, you will have to get someone qualified to look at it.

 

[Minidriver]

That boiler should supply ~ 6.8 LPM at 65C or ~ 10.5 LPM at 45C (from cold at 10C) so it should have no problem in supplying hot water at 4.5 LPM, its possible I suppose but unlikely that the flow switch (probably set to ~ 3 LPM minimum flow) is faulty and starting/stopping the burner but you should be able to hear this if you stand near the boiler.
Based on your flow of 4.5 LPM @ 3 bar would indicate that your plumber had adjusted it to give ~ 7.5 LPM at the original pressure of 8bar.
This reduced pressure is also the reason why you have to open the tap fully now vs 1/4 turn previously.
Possibly also fault may be with the boiler heat exchanger so as advised above, you will have to get someone qualified to look at it.

Thank you for that reply.

It will be due service soon so will get them to double check it all.