Damage new boiler by slightly increasing mains water pressure?

SubaruSeb

We had a new boiler installed by a nationwide portal in November and are really happy with the Worcester Bosch itself and also the service provided, which extended to them sending another plumber out recently to deflect the flue which was dripping directly onto our electric charge point.

Anyway, with our old boiler, we didn't give a second thought to going out in the street and slightly increasing the mains water pressure to get more 'woosh' out of the shower head, and to prevent a trickle coming from any taps when the washing machine was on or the toilet was flushed. Our kitchen stop tap is very stiff, so plumbers have always recommended adjusting pressure in the street.

Should we be okay slightly increasing the water pressure in the street now we've got this new Worcester Bosch, or might we overwhelm or generally break it, maybe if the actual boiler itself needs a setting changing or a valve adjusting too/instead? I know we could ask the portal who organised the installer, but we've already hassled them enough with the flue adjustment, so just wanted to ask here first for your kind thoughts. Thanks!

unforeseen

I don't understand why you should be adjusting the pressure in the first place. Most people have the stop taps fully open all the time. 

NSG666

The static pressure on the system is the same whether the stop tap is only open a bit or fully open.
Opening the stop tap will increase the flow and won't break anything. If the flow rate is very high then with a hot tap open fully the boiler might not have enough time to get the water up to the desired temperature. With a hot tap you can close it a bit to reduce the flow and increase the temperature but with a mixer shower you might not be able to control the flow.

GDB2222

The whole question is a bit unusual. Normally, stop valves are on or off. It seems that you have yours only part on. This has no effect on the pressure until you start drawing water, when the valve will reduce the pressure. 

Why do you think it’s necessary to do that?

WB boilers can cope with normal full water pressure. Indeed, the whole of the pipe work is under full pressure until you draw water.

SubaruSeb

The reason I asked about this is because since the WB boiler was installed, our mains shower has only given about 50% of the whoosh it did with the old boiler, and if someone uses another sink or flushes the loo, the shower more or less stops to a dribble.

For avoidance of doubt, the plumbing to the bath and shower was all renewed last summer, checked over, and produced a forceful head of water right up to the new WB boiler being fitted. In the past, going out to the pavement and opening the mains tap a bit more seemed to give a stronger shower flow.

neilmcl

SubaruSeb said:

The reason I asked about this is because since the WB boiler was installed, our mains shower has only given about 50% of the whoosh it did with the old boiler, and if someone uses another sink or flushes the loo, the shower more or less stops to a dribble.

For avoidance of doubt, the plumbing to the bath and shower was all renewed last summer, checked over, and produced a forceful head of water right up to the new WB boiler being fitted. In the past, going out to the pavement and opening the mains tap a bit more seemed to give a stronger shower flow.

What type and size of boiler did you have before fitting the Worcester and what size is the new one? Depending on the size (and I'm assuming you have a combi) the flow rate will be limited regardless of what the water pressure is.

And to answer your question, you won't damage the boiler but it's a bit of a pointless exercise to do so anyway..

TELLIT01

With a combi boiler the pressure in the shower, or any tap, will reduce when another tap is opened.  The stop tap being only partly open will affect the flow to everything, just as only partly opening any other tap affects the flow rate of the water from that tap.

SubaruSeb

Thanks for your help so far.

The old boiler was a Saunier Duval, also a Combi like our new WB, and I believe it was considered overkill for the size of the (standard semi detached) house by everyone who saw it, so was that why we used to get a strong force from the shower even if someone flushed the toilet, which didn't render it a dribble?

If moving to a less powerful but therefore more suitable, efficient and cheaper to run WB means we'll never get as strong a gush from the shower head, we'll just accept that if you're all saying adjusting the street tap won't make any difference. Cheers.

daveyjp

Your new boiler needed to be matched to your cold water flow rate.  If it wasn't and its too small its why you have a difference.

If you have high flow rate it is quite normal to have a boiler which is oversized for the number of radiators as hot water flow rate is more important to users.

neilmcl

SubaruSeb said:

Thanks for your help so far.

The old boiler was a Saunier Duval, also a Combi like our new WB, and I believe it was considered overkill for the size of the (standard semi detached) house by everyone who saw it, so was that why we used to get a strong force from the shower even if someone flushed the toilet, which didn't render it a dribble?

If moving to a less powerful but therefore more suitable, efficient and cheaper to run WB means we'll never get as strong a gush from the shower head, we'll just accept that if you're all saying adjusting the street tap won't make any difference. Cheers.

What model of WB boiler do you have exactly?

SubaruSeb

daveyjp said:

Your new boiler needed to be matched to your cold water flow rate.  If it wasn't and its too small its why you have a difference.

If you have high flow rate it is quite normal to have a boiler which is oversized for the number of radiators as hot water flow rate is more important to users.

Matched in the sense of configuration by the plumber who installed it, or matched in terms of we've gone for a boiler too weedy to handle our water flow? We used a few different online configurations, telling them the size of our house, the number of people in it, what we want/need, etc, and they all said a Worcester Bosch Greenstar 8000 Life Combi 30kW is sufficient. Oh well.