unvented hot water blow off

[buckley plumb]

just re done my unvenvented and 5 years ago was told if discharging into a soil stack then pushfit must be used just been told today it should be solvent weld what is correct . got part g and it does not realy state

 

[Megaflo-Experts]

MUPVC or trade name Terrain is acceptable to use for discharge.

Yes that sounds familiar - isn't the plastic used for boiler flues?

 

[kozak1968]

Yes keston boilers recommend it

 

[chris watkins]

MUPVC or trade name Terrain is acceptable to use for discharge.

No it is not (you & I may know it might be capable but the BS EN that they are all made to does not cover it) If it is inspected it will not pass & you would be asked to replace it at your cost.
It may be OK as flue pipe but that is not what the post is about.

 

[kozak1968]

Another grey area i see!

 

[buckley plumb]

The important factor is the type of plastic used - it needs to be able to withstand a 'large' quantity of boiling water, in the event of a big discharge.
As mentioned earlier, Polypropylene is the material required. This is used for push-fit pipes, traps, HepVo traps, etc.
Polypropylene can withstand around 120C, where as ABS is rated for around 70C, but can take 95C for several minutes.
Be aware that plastic soil stacks are generally ABS, but the expectation is that the water will have cooled down sufficiently before reaching the SVP!
I always find this a grey area and my preference where possible is always to use copper to discharge externally.

I'm renewing my G3 soon and I will quiz the tutor on this area, but I suspect no one will have a clear definitive answer!

i bet the training center where you go wont know none of them seem to i nearly failed as i argued glufit is no good

 

[ratrace]

Didn't want to start a new thread and found this whilst searching for my answer. Hope you dont mind me asking in here. I have a 10l unvented water heater to fit tomorrow. Just looking for confirmation really as i haven't done this before. Would it be correct to fit copper from the blow off to a tun dish adaptor on a hepvo valve then run 1"1/4 pushfit waste from there back into a 4 inch solvent weld stack? it would be really awkward to do in copper otherwise. Thanks.

 

[chris watkins]

Didn't want to start a new thread and found this whilst searching for my answer. Hope you dont mind me asking in here. I have a 10l unvented water heater to fit tomorrow. Just looking for confirmation really as i haven't done this before. Would it be correct to fit copper from the blow off to a tun dish adaptor on a hepvo valve then run 1"1/4 pushfit waste from there back into a 4 inch solvent weld stack? it would be really awkward to do in copper otherwise. Thanks.

First things first have you got your Part G ticket because you should be aware of what is required. I would always install the D1 pipe work in copper. What size is the T&P ?

 

[Megaflo-Experts]

Don't think you need G3 if less than 15 litres.

 

[ratrace]

I was under the impression that under 15l no ticket was required, has this changed or was it never the case? Alas i havent done unvented since my apprenticeship over 8 years ago. The T&P valve is 15mm. The D1 will be in copper.

 

[aaronsmith]

solvent weld plastic sags and warps under extreme heat of blow off,barrier hep2o sould be ok,but copper looks good IMO

 

[ratrace]

Cheers Aaron. Reading back in this thread the consensus seemed to be that pushfit was safer at a higher temperature then solvent as you mention and would be the option to use. Would you agree?

 

[chris watkins]

Don't think you need G3 if less than 15 litres.

I was under the impression that under 15l no ticket was required, has this changed or was it never the case? Alas i havent done unvented since my apprenticeship over 8 years ago. The T&P valve is 15mm. The D1 will be in copper.

All hot water systems of any size or shape require Part G ticket since it was updated in the 2010. It changed so the 15L demarcation went but you do not have to notify them to B.C. so long as they have all the manufacturers safety devices installed. Have a look (it's free) http://www.planningportal.gov.uk/uploads/br/BR_PDF_AD_G_2010_V2.pdf

Why not do your Part G ratrace ? what you asked sounds alright so long as the lengths of D1 & 2 are correct & you have the min 300mm between tun dish & first bend which in these small ones can be a problem.

 

[chris watkins]

Cheers Aaron. Reading back in this thread the consensus seemed to be that pushfit was safer at a higher temperature then solvent as you mention and would be the option to use. Would you agree?

How many more times YOU CAN NOT USE SOLVENT WELD (ABS or uPVC) its push fit only !!!!

 

[ratrace]

If you bothered to re read it instead of jumping on your high horse i wasn't disagreeing with it being 'push fit only'. I was merely re making that point with another forum member.

 

[chris watkins]

If you bothered to re read it instead of jumping on your high horse i wasn't disagreeing with it being 'push fit only'. I was merely re making that point with another forum member.

Sorry it was not aimed at you (& no hoses here, me old fruit) but just get a bit pee'd with repeating it.

 

[ratrace]

Fair do's i take it back. And thanks for your input. To answer your earlier question i will be sure to do the course when the opportunity to use it arises. Don't have hardly any call for it and can do without course fees that don't bring anything in.

 

[Sid Viscous]

Don't think you need G3 if less than 15 litres.

Not at the moment but my info is that's about to change to cover all unvented, however small

 

[Sid Viscous]

Sorry Chris, post #37 spot on dude

 

[stevetheplumber]

Re: unvented ho****er blow off

lets be honest not much has changed with the water heaters and what has could be dealt with via a tech update its more about the training industry and the legislaters being either one and the same or working very closely

 

[chris watkins]

Re: unvented ho****er blow off

lets be honest not much has changed with the water heaters and what has could be dealt with via a tech update its more about the training industry and the legislaters being either one and the same or working very closely

Well clearly not Steve, buy the number of posts on here & the fact it was all over the trade press at the time, so think we can safely say some form of training is required whether we need a 5 year turn around I would agree is a bit much but something, there where a lot of changes (after 2 people killed after accidents).