T&P Valve or Expansion Vessel

[FredTheDog]

Hi,

Just got back from a week with some friends for xmas, turned the hot water back on and within an hour or so I had hot water gushing from the T&P valve at the same rate the tank was filling. Turned off the hot water and water supply to the tank and the T&P valve stopped after a few mins....if I turn the knob on the T&P valve more water comes out at pressure.

Read somewhere there needs to be a bubble in the tank? But I also have a cream coloured expansion vessel piped into the HW pipework spaghetti, the middle of it is about the same height as the top of the tank. No manufacturer on it and cant see a shrader valve on it to check pressure either, just a bid black plastic thing on the top.

Going to another friends for New Year so want to fix pretty quick when I get back as the only way to shower is to turn on the water supply to the tank which wastes lots of water while we shower, then turn all off and wait for it to stop draining.

Its an Ariston WRc-NSF Tank....if that helps.

Any idea what the problem could be??

Thanks

FTD

 

[Dotty]

Re: T&P Valve or Expansion Vessel problem

Don't touch it. Get a plumber in with a g3/unvented ticket.

post a thread in the 'I'm looking for a plumber / gas engineer' section of these forums remembering to include your location - [DLMURL="http://www.ukplumbersforums.co.uk/im-looking-plumber-gas-engineer/"]I'm looking for a Plumber or Gas Engineer[/DLMURL]

 

[Roger Welton]

You shouldn't touch it unless you are suitably qualified (G3) get some one in is.

 

[Best]

You need an engineer who is qualified in unvented. It is the law & besides, very dangerous to not have them repaired & serviced (once a year) by someone competent.
You may have more than one fault with your unit.

 

[glenno1]

I agree this needs a suitably qualified plumber

 

[Best]

Take a look at Youtube video "Exploding water heater" if you want to see the result of an unvented with all it's safety parts failed.

 

[FredTheDog]

Thanks for the quick response everyone. Guess its more serious than I thought!

 

[townfanjon]

fred, its not serious, it just needs to be looked at by the right man with the appropriate qualifications rather than a plumber.

 

[Dotty]

Serious enough if you get it wrong...........

[video=youtube;61uDmQF5I2E]http://www.youtube.com/watch?v=61uDmQF5I2E[/video]

Fear keeps you safe!

 

[Mike Jackson]

If the T&P relief is discharging at full bore you should turn off the heat source but not turn off the cold supply unless the water is running cold. As well as to release excess pressure the T&P relief valve is designed to cool the water temperature down which it can't do if the incoming main has been shut off.

 

[Chalked]

Serious enough if you get it wrong...........

[video=youtube;61uDmQF5I2E]http://www.youtube.com/watch?v=61uDmQF5I2E[/video]

Fear keeps you safe!

if this is always mentioned / shown, when someone unqualified posts about a unvented cyl (slightly ott to me) .
shouldnt we show a boiler exploding when someone asks about taking the cover off?

 

[sheff paul]

Hi,

Just got back from a week with some friends for xmas, turned the hot water back on and within an hour or so I had hot water gushing from the T&P valve at the same rate the tank was filling. Turned off the hot water and water supply to the tank and the T&P valve stopped after a few mins....if I turn the knob on the T&P valve more water comes out at pressure.

Read somewhere there needs to be a bubble in the tank? But I also have a cream coloured expansion vessel piped into the HW pipework spaghetti, the middle of it is about the same height as the top of the tank. No manufacturer on it and cant see a shrader valve on it to check pressure either, just a bid black plastic thing on the top.

Going to another friends for New Year so want to fix pretty quick when I get back as the only way to shower is to turn on the water supply to the tank which wastes lots of water while we shower, then turn all off and wait for it to stop draining.

Its an Ariston WRc-NSF Tank....if that helps.

Any idea what the problem could be??

Thanks

FTD

''Run Forrest Run ''

 

[Dotty]

if this is always mentioned / shown, when someone unqualified posts about a unvented cyl (slightly ott to me) .
shouldnt we show a boiler exploding when someone asks about taking the cover off?

We have a system in place for gas, gas appliances and boilers, we don't yet for unvented but I would hope the co related deaths each year would be testament enough.

So overkill? Not overkill enough.

 

[Chalked]

Point taken .

 

[sheff paul]

if this is always mentioned / shown, when someone unqualified posts about a unvented cyl (slightly ott to me) .
shouldnt we show a boiler exploding when someone asks about taking the cover off?

They ought to show this on the unvented course

 

[Best]

I know risk of explosion is highly unlikely on a properly installed, if neglected unvented, but better people get someone to check it all. Usually the expansion vessels are down in air charge or the balloon membrane is burst, as we know. If the balloon membrane holes, then the mains water enters the thin ordinary steel vessel, rusts it & when it pinholes eventually, then mains pressure water will flood the place. The vessels are supposed to be periodically replaced.
But I came across a brand new install in an airing cuboard done by a plumber who had oddly screwed a 15mm lever valve into the relief valve (at the pressure reducing valve set) & then piped to the D 1 pipe!
Then he had reduced the D 2 pipe to 15mm below tundish & ran it below an upstairs bedroom floor & simply poked it through the outside wall to potentially scald somebody many feet below!

 

[Mike Jackson]

They ought to show this on the unvented course

They have done on the courses I've been on.

 

[Killy Bing]

They have done on the courses I've been on.

likewise!! Then again I've pretty much only done stuff at steve willis

 

[solutions]

if this is always mentioned / shown, when someone unqualified posts about a unvented cyl (slightly ott to me) .
shouldnt we show a boiler exploding when someone asks about taking the cover off?

You find the video of the people dying from the invisible odourless tasteless CO and I will post it on every diy boiler fault enquiry. Same goes for gas explosion. You find the footage it will get posted. It may be ott but so are safety campaigns for seat belts and not crossing train tracks. Most people just use common sense put on their seat belts, dont cross train tracks and call a qualified registered competent and ideally well recomended engineer to service and repair their boiler for everyone else their are scary videos.

 

[sheff paul]

They have done on the courses I've been on.

Took initial course in 2004, just popped in last monday and just took reassesment,got 1 question wrong (pats one self on back)