Condensation pipe size/material

[Dan the plumber]

Evening all,Bit of advice needed if poss; Currently doing a bathroom refurb & took the bath out today to discover the condensation pipe has been ran behind the bath in 15mm copper (bout 12ft of it as the airing cupboard is in the middle of the house!). The problem is I'm installing a shower cubicle on the same wall=will it be ok to rerun the pipe under the floor in poly then switch to copper externally!? Will 15mm be ok or should I upsize to 22mm!? Also, does it have to be solvent weld or will push fit suffice!? Thanks in advance for your help all

 

[Bartdude]

Do you mean a condense pipe from a boiler? If so it shouldn't be copper,condensate will eat through that.It should be solvent weld plastic.

 

[diamondgas]

Sure its the condensate nd not the safety blow-off pipe?

 

[Dan the plumber]

Yes sorry, a condense pipe is what I meant! It's from a Worcester combi boiler and think the label referring to the pipe work under boiler read "safety device" and terminates outside as a usual condense pipe does! Should I change the complete pipe run to solvent weld then!? Just out of interest, is it a big no no to run a condense pipe in poly push fit!? Just thinking out loud as will need to go through approx 15 joists and with poly would make life allot easier!

 

[diamondgas]

Dan do you know any gas safe engineers? Sounds like you're talking about PRV pipe but describing it as condensate ... Totally different my friend!

 

[Dan the plumber]

"Sure its the condensate nd not the safety blow-off pipe?" Steve you could be right as label does read "safety device" from memory!? How does this differ from a condense pipe!!? There is only 1 pipe that exits the property & this is that pipe!? Sorry if the above is a bit of a "fick" question.....gas is next on the adgender, when funds allow!!!!

 

[diamondgas]

sounds like you may have a none condensing boiler Dan if theres only one pipe leaving the boiler and venturing outside or to a waste pipe...
If that's the case you can re-route the pipe under floorboards to outside but should be falling all the way, copper I believe ... did all mine in copper anyhow!

 

[Dan the plumber]

Steve thanks for your help mate, appreciate it. Would it be wrong if I substituted copper for poly or is this a no go!? Running a 12ft length of rigid copper through 15 or so joists...and at a constant fall!!!!!!! I ain't looking forward to that task :-/ lol

 

[GQuigley67]

it will be water at 95 degrees if it ever did blow off, which would melt plastic so no. Is it not close to an outside wall where you can re-route it straight out the wall ??

 

[Dan the plumber]

it will be water at 95 degrees if it ever did blow off, which would melt plastic so no. Is it not close to an outside wall where you can re-route it straight out the wall ??

Unfortunately not, airing cupboard is middle of the house and is a terraced house so no external wall behind boiler either!Only other option would be to take it the other way into the bedroom & exit external wall at rear of property! What deg should the fall be!?

 

[GQuigley67]

you could discharge it into waste pipe via a tundish so it has an air break, are you able to do that ?

 

[diamondgas]

Well dan don't worry to much about a fall! as long as it isn't gonna trap water on it's way out, end of the day there's gonna be 3Bar pressure behind it worse case scenario .. I'm not up on heat carrying capacity of plastic pipe .. check out manufacturers info ... someone here might know the ins and outs ...

 

[Dan the plumber]

you could discharge it into waste pipe via a tundish so it has an air break, are you able to do that ?

Not really as the closest waste typically will be the shower waste and this will have to be run above board level as part of old style cast waste stack set up is installed!!!Guess I could possibly run the pipe downstairs then exit from there!?

 

[GQuigley67]

best checking out if you can use plastic pipe, I'm not too sure as I think you would need an air break before going to plastic.

 

[cjg]

prv should be run in copper all the way out and terminated on a u/bend or the new cowl fitting, under no circumstance should it run in plastic

 

[Dan the plumber]

prv should be run in copper all the way out and terminated on a u/bend or the new cowl fitting, under no circumstance should it run in plastic

The u/bend I can just about manage....it's the 12ft run of copper through a million & one joists I ain't looking forward to-lol :-/Thanks for the help guys, so looking forward to the fun fun fun day ahead tomorrow ;-)

 

[cjg]

dan the u bend should be faceing back intowards the wall, or fit the new pr cowl hope that helps

 

[AWheating]

prv should be run in copper all the way out and terminated on a u/bend or the new cowl fitting, under no circumstance should it run in plastic

there is no reason you can not run it in plastic aslong as you follow the regs and it enters an internal waste system. You can even run an unvented discharge into a plastic waste system providing you follow the regs and have permission off building control.

Push fit waste can take a higer temp than solvent weld.

 

[SimonJohns]

you could discharge it into waste pipe via a tundish so it has an air break, are you able to do that ?

This cannot be done. I know it sounds really stupid but discharging a systems water that will contain chemicals direct in to a waste system will contravene the regs.

Also it is mentioned about a uv d2 going to waste. That is fine as it is potable water. Even if it is class 2


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[GQuigley67]

all sorts of chemicals go into drains ? I have never had to do it and if I ever had to I would probably check the regs first but I was assuming since you can do it with unvented then it would be ok for the boiler, fair enough if you cant because of chemicals but not as if its going into the Rain water.

 

[AWheating]

seen it done loads, mainly in flats.

 

[cjg]

there is no reason you can not run it in plastic aslong as you follow the regs and it enters an internal waste system. You can even run an unvented discharge into a plastic waste system providing you follow the regs and have permission off building control.

Push fit waste can take a higer temp than solvent weld.

i think that u/v discharges at lower temp where as combi can be 110c at 3.5bar hence copper all the way, if i am wrong!!! i offer my applo
but better safe than sorry or sued regards,

 

[kay-jay]

i think that u/v discharges at lower temp where as combi can be 110c at 3.5bar hence copper all the way, if i am wrong!!! i offer my applo
but better safe than sorry or sued regards,

think thats the wrong way round mate. i thought unvented scenario at 3 bar boiling temp of water is about 135 degrees or thereabouts. imagine this blowing off and expanding 1600 times, much worse than what a combi can deliver i think but i stand to be corrected by the boiler guys as i just do unvented at moment.

KJ

 

[AWheating]

as kay-jay has said, the water in an unvented hot water cylinder will boil at a higher temp due to the pressure. temp pressure relief is set to go off at 90 - 95 degree. Any discharge at above 100 wont need a pipe anyway!!

 

[rawr]

the answer is no, run it in copper, 15mm is fine no need to go to 22mm

 

[Dan the plumber]

Thanks all for your help....opted for the safe option & have now ran it in copper all the way Luckily got away with running it down stairs into a store cupboard type room, then out through external wall! I even managed to get the fall in ;-)Just out of interest, is there any min/max height the u/bend should be on exit of building!? Installed around 7 ft from floor! Thanks again all

 

[PlumbersMate]

been working on a site and the PRV are run in 25mm Uponor Pipe (PLASTIC)

 

[AWheating]

is that on unvented? if so you would need written permission off building control, why is that being used? where does it run to?

 

[Nat]

You can run discharge pipework in plastic. As stated before has to be of push fit variety and not solvent weld.You can discharge it into internal plastic stack as long as there is a tundish so you can tell its discharging.If your discharge point is under 2 metres in height in a public area or accessible to children you might want to think about fitting a cage around it.

 

[AWheating]

on unvented you can only run in plastic if building control agrees, you need to fit an hepvo valve also after tundish to stop smells

 

[PlumbersMate]

yeh they are on unvented AW. Must have permission as its housing for a council. The PRV comes down from first floor in uponor, then discharges out the wall in 28mm copper. Don't know what its being discharged to yet as they aren't finished. We have to just run them down and out the wall at the moment

 

[AWheating]

what size is the pipe? are you sure its not the uponor pipe thats got an alu layer inside? if the manufactures say it can take the temp and its sized to meet the regs im guessing its fine. If i was your boss id make sure its all in writing inculding calulations just incase a few years down the line questions are asked.

 

[PlumbersMate]

It is the one with the layer inside mate yes, alot more rigid than normal plastic pipe, and I assume alot higher temp resistance? Pretty simple to use though, although the 10/12mm stuff for radiators from manifolds can kink when it fancies it! lol Can be a pain

 

[AWheating]

with this pipe you would have to be using the 32mm to replace a 22mm copper discharge pipe, or a 40mm to replace a 28mm copper discharge pipe. i dont know the price of these sizes but im guessing you ae not saving much if anything?

its rated at 95*c so its on the min limit i guess