Water heater issue

grousedogtom

Hi, I was asked to check a water heater in a milking parlour, the problem occured when there was a leak on a cold pipe elsewhere on the farm. The incoming cold water was switched off to fix the leak and while fixing the leak a supply of very hot water started flowing through the pipe which is a cold pipe. The distance from the water heater and the damaged cold pipe is a good bit about 20 meters at least. My question is could the hot water have siophened back through the cold pipes when mains water was switched off. If so should a non return valve have been fitted on the heater incoming cold supply . Could the heater be faulty to allow this to happen? . Many thanks

Billy Bunting

Water heater ??

grousedogtom

Billy Bunting wrote: »

Water heater ??

Yes???

If its a unvented water heater be careful as these are rarely fitted safely and can damage people, property or both.

scudo2

1. What type of heater. Vented, un vented. Heated off seperate boiler or directly .

2 Yes it will syphon back if cold supply cut at a lower level.

3 Check all appropate safety. ie safety valve, expansion tank.

4 fit non return if you think it needs it. But why, if it worked properly before the leak?
Distance had no bearing on the hot water coming back to you.

5 For safety, you should consider, or fit a n electric pressure switch to shut it off in case of possibilty of further leaks.

Hope this helps.

grousedogtom

It's an Atlantic electric water heater unvented, similar to attached photo

grousedogtom

http://www.google.ie/search?q=Atlantic+water+heater&client=tablet-android-google&rlz=1Y3KTZR_enIE532IE532&source=lnms&tbm=isch&sa=X&ei=qjTfUc_6OfKh7AaRgIGYDA&ved=0CAkQ_AUoAA&biw=800&bih=1232#biv=i%7C7%3Bd%7Cokhp-lm588JgyM%3A

grousedogtom

grousedogtom wrote: »

It's an Atlantic electric water heater unvented, similar to attached photo

Get the manufactures instruction or a copy of G3 water regs and fit as per the manufactures/regs or you can leave yourself open to serious problems if any issues occur on this installation, be mindful also that unvented water heater for milking parlours often are specialist heaters that run at higher tempertures.

scudo2

gary71 wrote: »

Get the manufactures instruction or a copy of G3 water regs and fit as per the manufactures/regs or you can leave yourself open to serious problems if any issues occur on this installation, be mindful also that unvented water heater for milking parlours often are specialist heaters that run at higher tempertures.

Listen to above. I do a lot of milking parlors. If not done right they are dangerous.

scudo2

gary71 wrote: »

Get the manufactures instruction or a copy of G3 water regs and fit as per the manufactures/regs or you can leave yourself open to serious problems if any issues occur on this installation, be mindful also that unvented water heater for milking parlours often are specialist heaters that run at higher tempertures.

Listen to above. I do a lot of milking parlors. If not done right they are dangerous.critical that pressure switch be fitted.

gctest50

scudo2

gctest50 wrote: »

Your digging a hole for yourself with this one I think nifty 50. But good demo.
ps Is this another polish plumber video?

I see a lot of unvented installations and I have yet to see one that meets G3 fully.

The first time some plumbers find out about unvented regs is in court which is a bit late by then and they have no defence as they should understand water, heat and expansion. €20,000 in damages alone the last plumber was responsible for due to his lack of understanding.

Also the Crome safety valves fitted to most heaters on the cold water inlet is rated at 8/9 bar and normally incorporate a non return valve leaving no expansion for the heater. I mention this so that one isn't fitted to deal with the OP problem.

To any plumbers coming in to contact with these water heaters I would advise having a good working knowledge of the safety requirements for unvented water heaters.

I would ask if you could please take the time to do a quick safety check in schools and crèches on these water heaters as they can at times be fitted dangerously. I have sadly seen more than once water heaters fitted with the safety discharge valves pointing down towards where the little ones stand to wash their hands or with the discharge pipework pointing at a play area.

shane0007

Here's one that went wrong
Most people think the issue is pressure but it is not. It is temperature. Especially with milking parlours, you are bordering on the 2nd level of protection due to the higher temperatures required. There are only 3 levels. As Gary says, milking parlours are often a specialist heater designed specifically for that purpose but often a standard instantaneous heater is used to some of the protection levels removed or disabled.

scudo2

I could never figure out why a non return valve was part of the crome safety valve on a potentualy grenade/bomb depending on size. That allowed no room for expansion.
I always disconected the n/r valve to allow pressure to equalise to the mains pressure.(ie The old under sink heaters.)
Again this was 18-20 years ago when I was more into plumbing, I know reg's have improved since then.

scudo2

scudo2 wrote: »

I could never figure out why a non return valve was part of the crome safety valve on a potentualy grenade/bomb depending on size. That allowed no room for expansion.
I always disconected the n/r valve to allow pressure to equalise to the mains pressure.(ie The old under sink heaters.)
Again this was 18-20 years ago when I was more into plumbing, I know reg's have improved since then.

Don't hate the fitting, hate the fitter.

A expansion vessel teed in between the heater and the valve will deal with expansion.

scudo2

gary71 wrote: »

Don't hate the fitting, hate the fitter.

A expansion vessel teed in between the heater and the valve will deal with expansion.

Sorry but I don't know if your knocking me?

I'm talking about the old Atlantic under sink water heaters. I always fitted exp. Tank even tho it was not part of the man. Instulation guide and removed the n/r valve on the flimsey cheap supplied safety valve for extra safety.
Some times the "fitter"goes beyond the call of duty.
Water when heated has to expand somewhere. That's why I never trusted those flimsy safety valves that came with them.
Sorry but do you think I was wrong with this approach, and if yes, why?
Thanks.

scudo2

scudo2 wrote: »

Sorry but I don't know if your knocking me?

I'm talking about the old Atlantic under sink water heaters. I always fitted exp. Tank even tho it was not part of the man. Instulation guide and removed the n/r valve on the flimsey cheap supplied safety valve for extra safety.
Some times the "fitter"goes beyond the call of duty.
Water when heated has to expand somewhere. That's why I never trusted those flimsy safety valves that came with them.
Sorry but do you think I was wrong with this approach, and if yes, why?
Thanks.

I'm not knocking you, I merely pointing out its not the fittings that causes the problems but the installers lack of understanding of pressurised hot water systems.

I would never interfere with a safety device, I would install a heater as per manufactures instructions or G3 water regs, so if there's any issues down the road it's with the regs and not with me.

Personally I would disregard the Crome 8 bar safety valve for a separate non return valve and 6 bar safety valve.

The 6 bar would allow me to fit a tundish then terminate the pipe work to a safe place, I would fit expansion vessels, pressure reducing valves when required.

The only plastic I use is me visa as plastic pipe and unvented don't go together well.

scudo2

gary71 wrote: »

I'm not knocking you, I merely pointing out its not the fittings that causes the problems but the installers lack of understanding of pressurised hot water systems.

I would never interfere with a safety device, I would install a heater as pe







r manufactures instructions or G3 water regs, so if there's any issues down the road it's with the regs and not with me.

Personally I would disregard the Crome 8 bar safety valve for a separate non return valve and 6 bar safety valve.

The 6 bar would allow me to fit a tundish then terminate the pipe work to a safe place, I would fit expansion vessels, pressure reducing valves when required.

The only plastic I use is me visa as plastic pipe and unvented don't go together well.

Cheers Garry.
Thanks for reply. No offence taken mate. This is what the BOARDS is for, talking.
ps have no idea where the talk of plastic came in but please feel free to send on your PIN No.
Cheers again,
I'm sure we'll debate again soon!

scudo2

scudo2 wrote: »

Cheers Garry.
Thanks for reply. No offence taken mate. This is what the BOARDS is for, talking.
ps have no idea where the talk of plastic came in but please feel free to send on your PIN No.
Cheers again,
I'm sure we'll debate again soon!

That's me just venting:eek: as plastic pipe is commonly used on unvented without the installer taking into account the relationship between pressure and temperture then looking to see what impact it has on plastic pipe.

grousedogtom

scudo2 wrote: »

Listen to above. I do a lot of milking parlors. If not done right they are dangerous.

I didn't install the heater, it's installed about 5 years

grousedogtom

grousedogtom wrote: »

I didn't install the heater, it's installed about 5 years

If you're working on it then you have "DUTY OF CARE" which puts you in the hot seat if things ever went pear shaped(god forbid)