Pressure drops after a few seconds

[Darren Scott]

Hi, wonder if anyone can offer me any advice. Had an old gravity fed system replaced with a sealed pressurised hot water system. When installed it was great (a few months ago) however now its not great at all. Pressure is great when you first turn on the taps/shower but then drops off after about 5-7 seconds. Shower was really powerful when first done but now back to not much better than gravity system. Plumber that fitted it is not available now so cant ask him....any ideas. I am pulling what little hair i have left out after spending £3500 on having this fitted. Any suggestions greatly appreciated. thanks.

 

[Scott_D]

Any pictures?
Has any work been done?
valves closed?
Water main work in the street?

 

[Best]

Plumber should be giving you warranty on his work.
You need an unvented qualified plumber to work on, or check the unvented cylinder and any of its components.
Is the mains cold flow okay?
You might have debris in filters or airators of shower and taps.
But most likely you have a main stopcock turned nearly off, or (fault at the units works, which needs a G3 qualified plumber to sort.)

 

[Darren Scott]

Any pictures?
Has any work been done?
valves closed?
Water main work in the street?

Hi, thanks for the response. The only work done since is that the water meter feed to the 22mm feed to the tank had a short 15mm section as the plumber was not able to get hold of the 22mm fitting to the water meter when he installed. So now its 22mm all the way, assuming this would increase water flow but would it decrease pressure? There was a problem in the cold weather 5-6 weeks back that impacted village supply but thats all back to normal now..neighbours all reporting pressure is fine again. No valves closed, checked the water meter valve and its a quarter turn valve that is fully open.
thanks

 

[Darren Scott]

Plumber should be giving you warranty on his work.
You need an unvented qualified plumber to work on, or check the unvented cylinder and any of its components.
Is the mains cold flow okay?
You might have debris in filters or airators of shower and taps.
But most likely you have a main stopcock turned nearly off, or (fault at the units works, which needs a G3 qualified plumber to sort.)

Yes, long story on the plumber front...wont bore you with it here. Mains flow seems ok but again it drops off after a few seconds. The issue is at all taps so debris unlikely on the taps etc, is there somewhere else that this could be a problem (maybe the pressure control valve on the incoming before the tank?)

 

[Best]

You could get debris coming from the mains cold in valves and filters if work has been done in the roads

 

[Best]

Yes, long story on the plumber front...wont bore you with it here. Mains flow seems ok but again it drops off after a few seconds. The issue is at all taps so debris unlikely on the taps etc, is there somewhere else that this could be a problem (maybe the pressure control valve on the incoming before the tank?)

We can’t really comment on unvented cylinders here on open forum as it is illegal to work on them unless qualified and they are potentially dangerous if done wrong.
Flow is blocked somewhere most likely and a G3 plumber would need to see where.
Remember you will have at least one year warranty on all unvented components and probably 25 years on the unit, providing it is serviced once a year.
So you shouldn’t pay if any part is faulty, unless debris is the cause

 

[Darren Scott]

We can’t really comment on unvented cylinders here on open forum as it is illegal to work on them unless qualified and they are potentially dangerous if done wrong.
Flow is blocked somewhere most likely and a G3 plumber would need to see where.
Remember you will have at least one year warranty on all unvented components and probably 25 years on the unit, providing it is serviced once a year.
So you shouldn’t pay if any part is faulty, unless debris is the cause

thank you for the response, it is very much appreciated. thanks