Loss of water pressure inside house (fine at street)...

[robdarroch]

Hi,

I've had terrible water pressure in the house since we moved in, so bad I've been advised I can't get a combi boiler & can't have a couple of taps on at once or have a decent shower.

Had United Utilities out (who confirmed all is well at street level, way over the level at which they have to act) & a plumber out who did a flush of the system which had no impact at all (for £100).

Yesterday, I had to change a tap handle as it had seized. As I removed the handle there was an escape of air. When I replaced the handle and turned the water back on it was literally bouncing out of the sink, the pressure was fantastic. Unfortunately, after the rest of the taps in the house had been used, the pressure pretty quickly returned to it's former self.

With my extermely limited plumbing knowledge, it seems to me that some air must be getting in the system - can anyone suggest how to whether a) there is another explanation or b) if it does seem like air is getting in, how to identify/fix the problem?

I don't mind if I have to get someone in to do it but I don't want to keep getting unnecessary jobs done which don't rectify the problem.

For background, I have an unvented hot water system with a 'megaflo' system. From reading on here, this system effectively has your hot water running at mains pressure - the pressure on the hot water is ineed the same as the cold... both rubbish! This system sounds ridiculously complicated so could this be the source of the problem?

Any suggestions will be really appreciated! It's so frustrating now that I know the pressure into the house is good, a decent shower would be amazing!

 

[picasso]

Get the pressure reducing valve changed on your megaflo.

 

[robdarroch]

Great, thanks for that. I didn't realise that the megaflo would have any impact on the cold water as well as hot water pressure. The megaflo is well overdue a service so I'll get someone to have at the pressure valve whilst they're at it.

 

[ALCPlumbing]

If your megaflo was installed properly your incoming mains will pass through the pressure reducing valve then tee off to supply the cold taps and through the cylinder to feed your hot taps. This way there is equal pressures at all of the outlets. There is probably an issue with the pressure reducing valve which is why there is a significant drop in pressure throughout your house. Any decent plumber should have diagnosed that pretty quickly.

 

[TCCHeating]

I think it may be possible that the op could be getting pressure and flow mixed up.

There could possibly be a problem with the supply pipe between the main in the street and the house. (Hence why united utilities say all is ok). If possible, turn off the supply at the stopcock on the road. Cut into the supply after it enters into the house, before the cylinder. Then connect a hose and see what the flow is like when you turn the stopcock back on. If it is still poor, then suspect the pipework between street and house. If it is good, then suspect the prv on the cylinder.