Loss of hot water pressure - restricted flow

Postby TwinkleBel » Sat Jan 19, 2008 2:02 pm

For the last few months, I have had reduced/non-existent flow of hot water out of my taps: kitchen, bath and basin.
Water is hot when it [i]does[/i] come out, but often there's
- no water coming out...
- or there is a pathetic dribble...
- or there is a long lag (2 mins-20mins).

I live in a 6th floor flat in London, so I expect problems with water pressure every now and again (Thames Water leaks, high demand, etc.) but this is happening regularly - both at high demand times and low demand times (e.g. 3am) and I have additional pumps (in my flat) for the CH and HW.

Thames Water say pressure to building is average 2.2-2.4 bar.
Pressure valve gauge under kitchen sink is at over 1 bar (and has remained stable for last 2 years) but this does not accurately reflect the pressure coming out of the HW tap.

On opening hot water tap, if there is HW, I can hear the pump working, but not a peep when there is no water flowing.

Potterton Prima 40F boiler 'seems' OK as CH working fine.

I am tempted to treat it as an air-lock and follow the [url=http://www.diydoctor.org.uk/projects/curingairlock.htm]article[/url] but worried that if it's limescale build-up this will cause a problem.

The flat is 50 years old and looks ancient. Could it be that it's on its last legs or something more sinister?

Any ideas? Thanks in advance!
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Joined: Sat Jan 19, 2008 11:54 am


Simply Build It

Postby TwinkleBel » Sat Jan 19, 2008 9:05 pm

Apologies - I seem to have posted this in the wrong forum.
Just submitted the question to the "Plumbing Forum" as I wan't sure how to move it.
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Joined: Sat Jan 19, 2008 11:54 am

Postby htg engineer » Sat Jan 19, 2008 9:10 pm

Unless your hot water is supplied by Thames Water then your going down the wrong path.

What is you cold water pressure like ? good i imagine - this is the pressure the water company is talking about being at 2.2-2.4bar.

Is there a Elson Tank or cylinder in your flat ? if yes, then it's hear you need to be checking. Probably ball valve problem or airlock in the hot water pipes, can be freed by backfilling.

As you don't seem to have any knowledge of plumbing systems - i'd get in a professional to sort the problem.

Also - wouldn't you say this was a plumbing question ?
htg engineer
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Joined: Tue May 22, 2007 5:22 pm

Postby TwinkleBel » Sat Jan 19, 2008 9:21 pm

Yes, thanks. You're right about it being a plumbing question. (I was looking through both forums when I posted it in the wrong one - sorry!)

You are also correct in that I have very little knowledge on the subject.
Was just asking on the off-chance it would be a simple task to trouble-shoot as I am completely skint.

Gonna have to bite the bullet and borrow some dosh for a pro as you suggest if anything more than a flush is required.

Thanks for the response!
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Joined: Sat Jan 19, 2008 11:54 am

Postby TwinkleBel » Wed Jan 23, 2008 11:07 pm

Plumber has been around and it appears to be due to the floor switch in the HW pump that is sticking.
(Fingers crossed that a replacement will sort it)
Posts: 9
Joined: Sat Jan 19, 2008 11:54 am

Postby TwinkleBel » Sun Feb 17, 2008 1:40 pm

Update to original thread:
Plumber fitted new 2 Bar pump (to replace original 1.2 Bar pump.
Hot water flows like never before - "a tamed tsunami".

Problem Resolved!
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Joined: Sat Jan 19, 2008 11:54 am

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