Dangerous Plumbing in 7 Year Old House - Who's Liable?
Discussion
Quick summary - our water system could lead to scalding if the cold water failed because of a plumbing valve that wasn't fitted when the house was built. Is it our responsibility to fix it, or the original installers?
The detail - we own a seven year old house (we are the second owners) and have a Megaflo hot water system made by Heatrae Sadia. For those that don't know, and the little I do, one of the benefits of this system is to deliver hot water at mains pressure.
This includes our shower, which we've had a recent leak with but is now fixed. When in the airing cupboard, the Aqualisa shower engineer who fixed the shower noted the missing valve.
What follows now is a very simple explanation of part of the system relevant to the problem. Cold water is supplied into the base of the Megaflo tank via one pipe. The cold water passes into the Megaflo where it is heated and delivered, under pressure, to the hot water taps and to the shower.
Also coming off the cold water pipe, before it goes into the Megaflo, are the pipes feeding the cold water taps and the cold water to the shower.
What this means is that if the cold water supply failed the hot water, under pressure in the Megaflo, could return back down the cold water pipe. In the case of the shower, the cold water feed would start delivering hot water and you would have two feeds both delivering hot water. If you're unlucky enough to be in the shower at the time, this could be dangerous.
To avoid this circumstance, a non-return valve is fitted to the cold water feed of the Megaflo preventing the return of hot water down the wrong pipe. The Aqualisa engineer noticed that it is this valve that was missing.
Our house is seven years old and I have spoken to the developers Twigden, actually part of the Kier Group. They were able to tell me the plumbers they used. I have contacted the plumbers who tell me that inclusion of a non-return valve was NOT part of the Megaflo specification/installation in 2003.
The shower engineer has spoken to Heatrae Sadia who say that it was part of the specification.
I believe that, if this is as dangerous as I'm lead to believe, that it's not my responsibility to fix it. I appreciate that the remedy is relatively straightforward, and that the risks of failure of the cold water during a shower is minimal, but I don't think that is the point.
All I have, by way of documentation, is the Aqualisa engineer's report. Does anyone have any advice on how I can approach this problem with the various suppliers, to arrive at the best result?
The detail - we own a seven year old house (we are the second owners) and have a Megaflo hot water system made by Heatrae Sadia. For those that don't know, and the little I do, one of the benefits of this system is to deliver hot water at mains pressure.
This includes our shower, which we've had a recent leak with but is now fixed. When in the airing cupboard, the Aqualisa shower engineer who fixed the shower noted the missing valve.
What follows now is a very simple explanation of part of the system relevant to the problem. Cold water is supplied into the base of the Megaflo tank via one pipe. The cold water passes into the Megaflo where it is heated and delivered, under pressure, to the hot water taps and to the shower.
Also coming off the cold water pipe, before it goes into the Megaflo, are the pipes feeding the cold water taps and the cold water to the shower.
What this means is that if the cold water supply failed the hot water, under pressure in the Megaflo, could return back down the cold water pipe. In the case of the shower, the cold water feed would start delivering hot water and you would have two feeds both delivering hot water. If you're unlucky enough to be in the shower at the time, this could be dangerous.
To avoid this circumstance, a non-return valve is fitted to the cold water feed of the Megaflo preventing the return of hot water down the wrong pipe. The Aqualisa engineer noticed that it is this valve that was missing.
Our house is seven years old and I have spoken to the developers Twigden, actually part of the Kier Group. They were able to tell me the plumbers they used. I have contacted the plumbers who tell me that inclusion of a non-return valve was NOT part of the Megaflo specification/installation in 2003.
The shower engineer has spoken to Heatrae Sadia who say that it was part of the specification.
I believe that, if this is as dangerous as I'm lead to believe, that it's not my responsibility to fix it. I appreciate that the remedy is relatively straightforward, and that the risks of failure of the cold water during a shower is minimal, but I don't think that is the point.
All I have, by way of documentation, is the Aqualisa engineer's report. Does anyone have any advice on how I can approach this problem with the various suppliers, to arrive at the best result?
jonnylarge said:
The shower engineer has spoken to Heatrae Sadia who say that it was part of the specification.
Something official with a date on it would seem to be a good start. However, if the developer says 'tough', what can you actually do to make them fit it? You may just end up in a two-year Mr Angry battle for the sake of £50.I've had the cold feed fail in a shower before. Very very unpleasant. Hot water fed from a tank presurised from a loft tank, cold straight from outside. A sheep had knocked the little dam that provided the cold water input.
Ended up leaping from the shower and then jsut scraping the suds off, before strolling up the hill to fix the dam.
When in Wales, don't shower!
Ended up leaping from the shower and then jsut scraping the suds off, before strolling up the hill to fix the dam.
When in Wales, don't shower!
A mains pressure hot water cylinder is common in New Zealand - and I can't see how the lack of a non return valve makes it dangerous in reality. The water at the bottom of the cylinder will be cold in any case, and the amount of water that would feed back down the cold feed would be minimal (there wouldn't be any hot pressure either) if the cold supply failed.
A much more likely scenario is failure of a tempering valve (stuck in hot open position), then subsequent failure of a thermostat - potential boiling water from the hot tap.
In many cases the best thing to do is set the thermostat to a sensible compromise of 50-55c and ignore all the rubbish about instant death from legionniares disease.
I'm in the fortunate position of using a heat pump for hot water with the thermostat set to 48- safe and cheap.
A much more likely scenario is failure of a tempering valve (stuck in hot open position), then subsequent failure of a thermostat - potential boiling water from the hot tap.
In many cases the best thing to do is set the thermostat to a sensible compromise of 50-55c and ignore all the rubbish about instant death from legionniares disease.
I'm in the fortunate position of using a heat pump for hot water with the thermostat set to 48- safe and cheap.
jonnylarge said:
Cold water is supplied into the base of the Megaflo tank via one pipe. The cold water passes into the Megaflo where it is heated and delivered, under pressure, to the hot water taps and to the shower.
Also coming off the cold water pipe, before it goes into the Megaflo, are the pipes feeding the cold water taps and the cold water to the shower.
What this means is that if the cold water supply failed the hot water, under pressure in the Megaflo, could return back down the cold water pipe.
How?Also coming off the cold water pipe, before it goes into the Megaflo, are the pipes feeding the cold water taps and the cold water to the shower.
What this means is that if the cold water supply failed the hot water, under pressure in the Megaflo, could return back down the cold water pipe.
Has the Megaflow got a pump? If so - the pump will not suddenly reverse.
If no pump, the lack of pressure in the cold will stop the hot too.
Unless you have an air accumulator (unlikely) which will not last for long.
Doesn't sound at all unsafe to me, if you think a non return valve will help then spend the 5 minutes and £15 required to fit one. I'm struggling to think of a reason for your post in fact - can a PHer really be chasing dubious blame on a non existent issue instead of just getting on with it?
Globulator said:
Unless you have an air accumulator (unlikely) which will not last for long.
It does, yes.It has a vessel attached to take the expansion when the water heats, so once the incoming pressure fails it might then dump that accumulated pressure back up the inlet pipe...maybe 8 litres??? That's quite a lot through a shower head.
HOWEVER!
I still think the PRV group has an NRV incorporated.
Ferg said:
I still think the PRV group has an NRV incorporated.
I've seen cylinders with the NRV seperate to the PRV group. I'm sure Centre Brand Cylinders have this set up.spikeyhead said:
I've had the cold feed fail in a shower before. Very very unpleasant. Hot water fed from a tank presurised from a loft tank, cold straight from outside. A sheep had knocked the little dam that provided the cold water input.
Ended up leaping from the shower and then jsut scraping the suds off, before strolling up the hill to fix the dam.
When in Wales, don't shower!
That is one of the reasons why you shouldn't have mains and low pressure water mixing. Ended up leaping from the shower and then jsut scraping the suds off, before strolling up the hill to fix the dam.
When in Wales, don't shower!
If they are both tank fed, the connection for the cylinder should be higher than the cold feed, so if the mains is disturbed and the tank runs dry, the hot water will stop first.
Ferg said:
I still think the PRV group has an NRV incorporated.
Cold water inlet control group consisting of pressure reducing valve set at 3.5 bar, an expansion valve set at 6.0 bar and a Neoperl single check valve cartridge (suitable for backflow protection against fluid category 2). Maximum supply pressure 16.0 bar. Ricky_M said:
Ferg said:
I still think the PRV group has an NRV incorporated.
I've seen cylinders with the NRV seperate to the PRV group. I'm sure Centre Brand Cylinders have this set up.spikeyhead said:
I've had the cold feed fail in a shower before. Very very unpleasant. Hot water fed from a tank presurised from a loft tank, cold straight from outside. A sheep had knocked the little dam that provided the cold water input.
Ended up leaping from the shower and then jsut scraping the suds off, before strolling up the hill to fix the dam.
When in Wales, don't shower!
That is one of the reasons why you shouldn't have mains and low pressure water mixing. Ended up leaping from the shower and then jsut scraping the suds off, before strolling up the hill to fix the dam.
When in Wales, don't shower!
If they are both tank fed, the connection for the cylinder should be higher than the cold feed, so if the mains is disturbed and the tank runs dry, the hot water will stop first.
Could I start by thanking those of you with the relevant expertise for replying to the thread.
Don't get me wrong, this may be a trivial issue. Sadly I don't have the relevant expertise to judge that...and when you look at the complex pipework involved (see photo below), I'm not even going to try. That's where a community such as PH comes in. Even if I don't get, or require, a fix then it's still an interesting thread to me, and maybe someone else in the future.
So, our system:
Just to redress Caziques reply, where the cold water feed (bottom left to right pipe, with yellow handled shut-off valve) disappears behind the wooden shelving, it is very warm to the touch - three hours after the boiler heating that cold water went off).
The focus of the thread seems to be the PRV, and whether it contains an NRV. I have taken a close up of the words on what I believe is the PRV (labelled "cold water valve set") and I'm not sure it mentions an NRV component:
Again, I'd really appreciate the relevant experts to offer some guidance.
Edit: Photo here on Flickr if you want to add Notes?
Don't get me wrong, this may be a trivial issue. Sadly I don't have the relevant expertise to judge that...and when you look at the complex pipework involved (see photo below), I'm not even going to try. That's where a community such as PH comes in. Even if I don't get, or require, a fix then it's still an interesting thread to me, and maybe someone else in the future.
So, our system:
Just to redress Caziques reply, where the cold water feed (bottom left to right pipe, with yellow handled shut-off valve) disappears behind the wooden shelving, it is very warm to the touch - three hours after the boiler heating that cold water went off).
The focus of the thread seems to be the PRV, and whether it contains an NRV. I have taken a close up of the words on what I believe is the PRV (labelled "cold water valve set") and I'm not sure it mentions an NRV component:
Again, I'd really appreciate the relevant experts to offer some guidance.
Edit: Photo here on Flickr if you want to add Notes?
Edited by jonnylarge on Monday 9th August 23:12
Looks like there is a big accumulator there - so I'd then try the ultimate test:
1) turn on the hot and cold taps.
2) Wait for the hot tap to become hot.
3) Switch off the cold supply
4) See if the cold tap gets hot
If the cold water does get hot then you a) have an issue and b) know there is no functioning NRV, so you can then proceed to stage 5 as needed:
5) Fit NRV on the cold feed to the hot water system.
Sound like a plan?
1) turn on the hot and cold taps.
2) Wait for the hot tap to become hot.
3) Switch off the cold supply
4) See if the cold tap gets hot
If the cold water does get hot then you a) have an issue and b) know there is no functioning NRV, so you can then proceed to stage 5 as needed:
5) Fit NRV on the cold feed to the hot water system.
Sound like a plan?
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