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Discuss PRV and condense discharge form a combi boiler in the Central Heating Forum area at

Good day all, First and foremost i am not a boiler installer or gas registered, therefore i do not touch this element of plumbing, but i am after the correct advise regarding the following issue.
I have had a gas installer who has piped the PRV and condense discharge pipe from a combi boiler directly into a 35mm waste pipe which has been concealed within a false wall. Both of these connections are upstream of a basin waste connection, the condense flexi pipe is just pushed into the top of the 35mm waste pipe, and the PRV has been pushed into an elbow socket and siliconed in place! - all on the same run, and discharge outside into a gulley.
Now, my understanding is that the condense discharge should be run in 22mm plastic and if connected to an existing waste pipe, must be done so after the basin connection or alternatively direct to outside and terminate into a gulley of some form. The PRV must be 15mm copper and terminate on an outside wall with either a returned bend on it or one of those "button" type connections. I am currently in dispute with the guy because i am not sure if this meets regulations. He is saying that this is acceptable and conforms to standard. As i have NEVER seen it piped this way, could you guys please advise me of the correct way that these should be installed? Thanks in advance.


Gas Engineer
You should be able to notice discharge from the prv either from external discharge point or a tundish fitted internally so you can see water running before it runs off in the hidden drains.


Staff member
S. Mod
Gas Engineer
..any pictures ?????


Have you checked the boilers MI's ?
no, i dont have the details. All im asking is the way that it has been fitted non compliance with regulations, should the PRV be discharge externally and should the condense pipe be plumbed in before the basin trap?


Gas Engineer
Mis of boiler will determine how your prv should terminate, condense tapped in after traps to assist in washing it away
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