Waste and boiler pipe in loft

[Loofah]

I'm hoping for an expert opinion or solution to this that my builder left me. The waste pipe vents into the loft space with the boiler condensate pipe (white) draining into it. The top had a rubber cap placed on and attempted to be siliconed in place but it came loose almost immediately and condensation from the warm pipe started running down the outside as it wasn't sealed. I've removed the rubber cap as it was useless and causing more problems than it was fixing.

I'm thinking a push fit 110mm pipe extension with a boss connection to sort the boiler pipe and an air admittance valve on top of that.

McAlpine Drain Connector Black 110mm - Screwfix

Order online at Screwfix.com. Drain connector with finned seal spigot for internal connection to 4"/110mm cast iron, plastic or clay and 1½" universal vent boss with blanking cap. Should only be fitted on ground floor due to a reduction in the internal outlet diameter of the boss pipe connector...

www.screwfix.com

FloPlast Push-Fit Air Admittance Valve Grey 110mm - Screwfix

Order online at Screwfix.com. Allows the free entry of air into the sanitary pipework system without the foul gases escaping into the building. Avoids the need to penetrate outer roof shell. It is recommended that air admittance valves are not used externally as environmental debris will affect...

www.screwfix.com

Is this a suitable fix?

 

[Hugh Jaleak]

I despair sometimes, I really hope it was a Qualified Gas Engineer who fitted the boiler, although they clearly don't know much about soil pipework....

What was there originally? Soil pipes don't usually just terminate in loft spaces with an open end! I'd hazard a guess the flexi vent pipe was connected to the end, to (correctly) allow the soil pipe to vent externally, or alternatively an AAV should have been fitted.

What should have been/should be done is, the condensate drain be connected to the soil pipe via a strap boss, and the pipe allowed to continue venting to atmosphere/left with the AAV on the top.

 

[thetman]

Thats awful, the 110 needs extended up with at least an AAV (durgo Valve) and a proper boss connection for the condensate.

There really should be a tundish on the PRV discharge as well

 

[Loofah]

It was / is quite a list of bodges my builder left. It sounds like my thinking above should suffice as a fix for now; ultimately we'll be converting the loft and the waste can be extended up and out.
This location is a new build extension so it's completely intentional from the plumber. The flex ducting is from the hob extractor; this is actually their second attempt at it. The first time they put white ducting through a 1cm gap (I kid you not) as the extractor came out under a joist which blocked most of the hole. It's hard to explain but suffice to say they were finally kicked off site.
Oh and there's a tundish but in a different location in the utility room directly under the boiler.
I also have water hammer but that's another problem

 

[Hugh Jaleak]

For a quick solution, stick one of these on the end of the pipe you've got, https://www.screwfix.com/p/floplast-push-fit-3-boss-single-socket-boss-pipe-grey-110mm/18246, (wont hurt being upside down), then the AAV in the spigot end. The AAV wont fit into a socket end and give an airtight seal.

 

[HERTS P&D]

Good shout Hugh.

Andy

 

[Loofah]

That's a great shout @Hugh Jaleak thanks

 

[Hugh Jaleak]

Should have said, (if you weren't aware), you'll need to chamfer the end of the existing pipe with a file before trying to push the fitting on, or you'll displace the seal.

 

[Jackrae]

Apart from that, the dip in the silver flexible will collect water and prevent whatever is connected to it from venting to atmosphere

 

[Loofah]

Apart from that, the dip in the silver flexible will collect water and prevent whatever is connected to it from venting to atmosphere

Not sure I follow that? If you mean the 22mm white pipe then there's no dip it's just my rubbish photo and the plumber's creativity in routing pipework. It should flow into the waste ok.

 

[Loofah]

@Jackrae sorry, I've just realised you mean the ducting!
Yes I agree, it's an awful arrangement and I'll one day sort it. The run is also further than it should be so working the extractor harder than recommended

 

[Loofah]

Finally got round to doing this. Not ideal and I should have removed an inch or so of the existing pipe to give a better runoff from the boiler. I also forgot to get an adapter so the boss is temporarily plugged with a rag.

 

[Madrab]

Sorted .... Certainly a lot better and tidier than it was and a lot more compliant.

Any reason you didn't want to extend the soil pipe up a little and then attach it to the black flexi vent and then up and out of the roof? It's so much better for drainage if the stack can release positive as well as negative pressure. An AAV will only vent negative pressure within the stack.

 

[Loofah]

This only a temp fix until we convert the loft. You can't really see where that Flexi goes but it's not in a helpful location! This should have gone vertically through the roof but they clearly could not be bothered.
This will do for now but I do need to replace a rag with something better

 

[Madrab]

Strangely enough 21.5 mm boss adapters aren't easy to find, if you get a 21.5mm to 40mm solvent weld reducer then use a 40mm rubber boss adapter, that'll sort you out.