Discharge pipes: Unvented water system (& central heatin

[cbasson]

Hello,

I am looking to switch over to a mains pressure from gravity system.

In the room where the cylinder will be sited there is a sink already.

Can the discharge pipe from the cylinders pressure and temperature relief valve be fed into the sinks waste pipe?

If so, can the discharge pipe from the central heating systems saftey relief valve run into the same pipe?


Thanks

 

[cbasson]

So I have seen the NHBC newsletter which states use of Hepvo Waterless valve, and not good idea to build into washing machine/sink waste pipe....

So my thought process is: the waste from the sink (& washing machine) is flowing somewhere. What is required to modify the pipework to incorporate a discharge pipe (using the Hepvo valve) rather then sticking another hole in the external wall.

The issue with sticking another hole in the wall is the other side of the wall is the front of the house, so would not look very good.

 

[Breesey]

It sounds as if you are not qualified to be doing this work yourself.

You can not use an existing waste pipe to run a discharge pipe to, via a hepvo or otherwise, for several reasons.

Get someone qualified in to advise you and do this work for you.

 

[muggles]

Standard waste pipe will not take the potential high temperatures associated with unvented cylinder discharge, so your entire waste run would need removing and re-doing in specialist High Temperature Rated waste pipework. Your CH relief pipe could be run into the same system but would need correctly modifying from the standard specification

You must be G3 qualified to install unvented cylinders and it is notifiable work to building control

 

[Breesey]

Plastic discharge pipe must not be used for 'regular' waste ie it is installed for discharge only.

 

[cbasson]

No chance i am doing this myself. I just want to know whats possible. My plumber wasnt very expansive when i questioned if there were any alternatives from just drilling a hole in the wall.

There is also a toilet waste pipe which goes through the room.

How much work/cost would there be involved in adapting the pipe system?

 

[cbasson]

Standard waste pipe will not take the potential high temperatures associated with unvented cylinder discharge, so your entire waste run would need removing and re-doing in specialist High Temperature Rated waste pipework. Your CH relief pipe could be run into the same system but would need correctly modifying from the standard specification

You must be G3 qualified to install unvented cylinders and it is notifiable work to building control

By entire waste run, does this mean all the way under the house to the street level or a shorter length?

 

[Breesey]

You can NOT use an existing waste pipe to run unvented discharge into - regardless what it is made of.

You either run a new (completely seperate) plastic (polypropolene that is) discharge into a soil pipe via a hepvo or a correctly sized copper pipe to outside per the regs.

The tundish needs to be easily visible.

If your plumber is not very 'expansive' maybe it is because he doesn't know. Does he have a G3 cert?

 

[SandyLyon]

The HepVo valve has to be installed in a vertical position and the 32mm waste pipe needs to be Polypropylene (Push Fit) and runs to a 4" soil stack with no other appliances connected to the discharge pipe,

See here http://www.nhbc.co.uk/NHBCPublicati...ical/StandardsExtra/filedownload,34921,en.pdf

 

[muggles]

needs to be Polypropylene (Push Fit)

Unless things have changed since I did my course, MuPVC solvent weld is also acceptable as it is HT rated. This is what I generally use as I believe it's safer - there's no risk of it pushing apart and boiling water going everywhere. I'll admit my error on saying it can be connected to other appliances though, late night brain fart, of course it must be a separate run

 

[Breesey]

Discharge pipework must be either copper or polypropolene...

 

[cbasson]

If your plumber is not very 'expansive' maybe it is because he doesn't know. Does he have a G3 cert?

Hmmm, good q...

Thanks all

 

[SandyLyon]

needs to be Polypropylene (Push Fit)

Unless things have changed since I did my course, MuPVC solvent weld is also acceptable as it is HT rated. This is what I generally use as I believe it's safer - there's no risk of it pushing apart and boiling water going everywhere. I'll admit my error on saying it can be connected to other appliances though, late night brain fart, of course it must be a separate run

It has to be either copper or Polypropylene (push fit) no other plastic, it's in the approval doc / regs

 

[cbasson]

At the risk of asking a stupid question....

Soil stack.... there is a large vertical pipe in the corner of the room which the pipes from the washing machine, sink and toilet & bath run into. Which sounds like a soil stack from my brief education on t'interweb.

Is that what it is? Or is it just a large vertical waste pipe?

Anonomous forums. Priceless.

 

[SandyLyon]

At the risk of asking a stupid question....

Soil stack.... there is a large vertical pipe in the corner of the room which the pipes from the washing machine, sink and toilet & bath run into. Which sounds like a soil stack from my brief education on t'interweb.

Is that what it is? Or is it just a large vertical waste pipe?

Anonomous forums. Priceless.

The soil stack is normally approx 4" in dia, it will take the waste / solids into the below ground drainage system. It should also vent to atmosphere.

Your W.C.'s should connect to it and also waste pipes may connect into it or they could run to a hopper or gully.

Your W.C. Will defo connect into the soil stack