75mm trap

[jon]

I'm in the process of installing an Ideal Isar 30HE boiler, and the manual says if I'm connecting the condensate pipework to a soil stack (which I will be doing) that I need to fit a 75mm trap.

The questions are.

Do I fit the trap inside the house or outside, or doesn't it matter.

Where can I buy a 75mm trap to fit standard 21.5mm plastic overflow pipe (I've googled, froogled and poogled till blood comes out of my ears, but no luck), or do I buy a 32mm trap and then try and find 21.5mm to 32mm reducers.

Or don't I really need one (hoping this is the answer)

Cheers

Jon

[Christian McArdle]

Can you just use a washing machine style trap and stick the hose in the end with an air break? Only do this if the boiler manufacturer is happy to do so, as with some designs, they might worry about it exhausting through there if the boiler internal trap is empty or not specified.

Christian.

[fred]

In article , jon writes

Damned if I know, for my Keston they just suggest you make up a U-trap from overflow pipe and give it (IIRC) about 200mm depth. I did it with plain pipe while but another here (Andy Gabriel I think) used clear piping to check for flow and blockages, something which I omitted.

Could they be suggesting a bottle trap with a 75mm body? I can see the sense in that as you could easily clear it of crud and wash it out. If you decide to go for one of these then you can get adaptors for just about anything so you will be able to mate it up, just don't use an anti syphon one ;-).

Perhaps a call to their tech line is called for to get the whys and wherefors.

[Vaci]

I don't think you'll need to mechanically attach the 21mm overflow pipework to the 32mm pipework.

Sounds like you just need an arrangement similar to a washing machine trap. The overflow pipe can just drop vertically into the open end of the 75mm trap.

Vaci

[Andrew Gabriel]

Keston C25 doesn't require an external trap -- it has one internally. I used a 6" section of clear tubing in the pipework so I could see if the boiler was actually generating any condensate. It works, but when there's a steady stream, you can't really see what sort of rate it's running. If I did it again, I would used a sealed tundish.

Mine eventually couples up to a 32mm waste pipe from the bathroom washbasin. I used a trap on the washbasin with integral air admittance valve to be sure any suction in the waste pipe couldn't empty out the trap in the Keston, but this wasn't something the Keston instructions suggested or required. They did require the condensate pipework to be at least 32mm outdoors, which mine is by virtue of joining the wash basin waste before going out through the wall.

[Christian McArdle]

I get the impression that the boiler in question does have an internal trap and doesn't usually require an external one. I think it just needs an extra deep external one in this case as it is connected to a soil pipe, where pressure differences can suck small traps out easily.

Christian.

[fred]

In article , Andrew Gabriel writes

You had me worried there for a min as I knew I'd seen a spec for an external trap in the manual but it's for drainage of a long flue which I have in my installation so I have 2 condensate drains, one from the boiler and one from the flue. In my enthusiasm I have made traps for both.

[fred]

In article , Christian McArdle writes

Good point, that would make sense of the 3" requirement. It would also mean that my comment about _not_ using an anti syphon trap would be wrong too, my, I am having a good day.