Low Hot Water Pressure (on shower and all hot taps)

JimFred_2

Hi,
Recently my hot water pressure has been reduced to a trickle on the shower and hot water taps.

I have not carried out any DIY on the boiler/water system and the pressure on the cold water is fine.

The only things I've done is turned the radiators off due to the hot weather, leaving the bathroom radiator on and turned the boiler settings from winter to summer.

Reservoir tank in roof is filling up okay and at the normal level- hot water in tank in airing cupboard-pipes hot-backup immersion off.
No knocking of pipes.
Tank in the airing cupboard thermostat is set at 60

Boiler is a Glow Worm Energy Saver 40 (house built in 1999)

I did put the winter settings back to how they were on the boiler when I first discovered the problem and this changed nothing.

I would appreciate any pointer.....Cheers.

BobProperty

My immediate reaction is there's something in the hot pipework just after the HW cylinder. How you check and sort it is another matter as I'd want to see it first. It may be possible to back flow the hot from the cold and see if that moves anything. Can you look into the header tank and make sure there's nothing blocking the outflow pipe at the bottom?

adandem

We had this problem recently when we had a new bathroom fitted. You may well have an airlock in the system somewhere. Do you have a hot and cold fill on your washing machine? If so:-

Disconnect the supply pipes at the back of the washer (turn them into off positions first) and put the cold supply onto the hot inlet. Turn on the cold water. The water pressure should be enough to blow out any air.

It worked for us.

JimFred_2

Cheer for the swift reply BobProperty.

I've checked the header tank-it has 3 outlets at the bottom and all are clear.There is very little debris in the header tank (small amounts of sand).

The hot water runs from the shower and taps for about 30 seconds and then trickles.
Whilst the hot tap is on in the bath I can hear the water trickling from the header tank into the hot water tank.

Is there any risk to the system with the back flow?

Cheers

BobProperty

Do as Adandem suggests, but I think they missed out "open the hot inlet" before "Turn on the cold water". At the point the cold water is opened the higher pressure of the cold will push the water back around the hot system and back into the header tank.
The only risk is that the overflow from the header tank doesn't function properly and water spills out of the header tank. So long as the overflow works there shouldn't be a problem. I'd prefer to have two people do it, one operating the valves on the washing machine taps and the other looking at what's happening in the header tank.

JimFred_2

Cheers 'adandem' for the very handy tip.

Will give it a go later today.

JimFred_2

Cheers BobProperty.

I'll give it a go later today.

JimFred_2

It worked and only took several seconds to complete.
Best use two people as BobProperty said.

Just did as you said and we now have the original pressure back on the hot taps and shower.

Thanks for your help 'adanden' and 'BobProperty'.