Pressure relief pipe capped off

Eyattwop · Mar 3, 2018

My combi boiler (logic 30+) is on the 1st floor and the pressure relief pipe runs straight through the external wall, terminating outside.

The pipe has a grey plastic cap on it, and (admittedly without any ladders to get close) the cap looks like it makes the pipe permanent sealed. It doesn't look like any sort of clever mushroom style cap.

If this pipe really is sealed, what would happen if the system pressure got too high? Where is that water going to go?

Harvest Fields · Mar 3, 2018

Picture would be good

Eyattwop · Mar 3, 2018

Scott_D · Mar 3, 2018

Looks like a 22mm soldered cap

Gasmk1 · Mar 3, 2018

there is a sort of cap with a slit in it that you can get could be that one but you need to check

snowhead · Mar 3, 2018

Can't say I've ever seen or heard of anything other than this design;

15mm Mushroom Vent Pipe Cowl for Boiler Blow Off - flowflex components pipe cowl B270.26 - Leagrave Heating Supplies

It would have to be copper to take the potential heat, so a plastic one won't do.

Water will find the next weakest part and escape.

Has the discharge pipe always had this on?
When was it last serviced and did whoever serviced it look outside?

Scott_D · Mar 3, 2018

Thinking about it the early logics came with a premade PRV pipe with a lump of brass for the outside
Looked like this

firemant · Mar 5, 2018

It is a variant if the mushroom idea. Some guys use a 22 or 28 cap with a blob of solder, obviously with a gap between the pipe and the back of the cap. In the event of discharge the water will blow against the wall, rather than the passing pedestrian