Hi gents,

Bit of a strange one... asked a couple of plumbers met with a bit of puzzlement so turning to online and hopeful you guys can help.

We have dripping hot water taps and shower all over the house. Shower is the main problem as it isn’t a small drip. This only seems happens when the boiler kicks in and starts to heat the water - standard boiler with a hot water tank and pressure vessel.

I’ve changed out washers in shower (they are old gummers sirrus valves). Maybe improved slightly but still lots of dripping. Taps drip too so not convinced it’s just an old shower / one tap issue.

I can only imagine the increased pressure when the water gets hot it causing this.

Anyone got any ideas?

Cheers,

Calum

Thanks for getting back thescruff!

Boiler is a Worcester Bosch Greenstar 8000 35kw (been in less than a year) and the pressure guage reads 25.5 consistently irrespective if it’s working or not.  The other gauge above the expansion vessel which reads about 0.8 bar cold and around 1 bar when the water has been heated. It’s an unvented system.

Cylinder is a mega flow heatrae sadia.

Cheers

The expansion vessel is it white or red?

what is the unit for 25.5 it's normal in bars?

Is the boiler the life system?

Is the whole system the same age including the taps etc?

If the taps etc are older, what system was in place prior to the new boiler.

Silly question, what is the make/model of the taps and shower?

Is the cylinder a replacement for an unvented cylinder?

Is there any discharge from the pressure valves Cylinder or boiler?

Can you check it isn't 2.55 or anything other than pressure? if not get the installer to check it out under warranty. The boiler pressure should be around 1-1.3bar when cold. if however, it is 25.5 bar the boiler wound be scrap.

The red vessel should be reading 1-1.3bar when cold.

Ok back to the problem, do you know how to re-charge the cylinder? it will be in the manual and quite simple to do. normally you would get a discharge when they lose there charge but may be worth trying.

Have you any way of checking the mains and hot water pressures?

Thanks for your help with this - it is appreciated.

Pressure definitely reads 25.5 bar. The user manual mentions it as 'system pressure'. Manual mentions what to do if the system has low pressure but doesn't say anywhere about the system having pressure which is way too high....! I would have assumed a relief valve would have opened or the boiler would shut down to protect itself if the pressure was actually 25.5 bar wouldn't it?

I've put pictures in below of this and of the dent on the cylinder (after posting though.

Will certainly try recharging the cylinder. Don't have a way of checking the water pressure right now unfortunately but more than happy to purchase something if you think it might help. All I can say just now is that the water pressure for both hot and cold seems quite high all over the house.

Also just stuck a picture of the technical specs of the cylinder if that helps at all.

Border between South Lanarkshire / Scottish Borders. Really appreciate the help mate thanks. 👍

Phoned Worcester Bosch and they have said that the boiler pressure is fine. Apparently because it isn't a system or a combi boiler the pressure sensor is essentially not connected so the reading is obsolete.

The boiler is due it's service next month anyway so will ensure then that the engineer is happy with this too.

Results of the water test:

Cold Feed - 33 litres per minute
Hot Feed - 21 litres per minute



I've posted another album with as many pictures as I can think might be useful....