Use of compression fittings on boiler discharge pipe

[James Carmichael]

Hi All,

SUMMARY: Can I use a copper compression fitting on the expansion discharge pipe of a gas boiler?

I have a a Vaillant system boiler, about 5 years old. I need to change the route the expansion relief/discharge pipe takes.

I know that the run must be in continuous copper pipe, the end of the pipe must be visible, shortest run with slope away from boiler and it must terminate in a safe place where people can't be scalded. I'll be going straight through the wall the boiler is mounted on and terminating outside with the usual 180 degree bend back into the wall.

Is there any reason why I can't use a compression fitting to make the join between the vertical pipe connected to the boiler and the horizontal run? I know it is normal to solder, but it's a bit cramped in there and I don't fancy wielding my blow torch so close to the boiler ... I assume this is ok as the final fitting to the boiler itself is just supplied as a 15mm compression?

Many thanks!

 

[Agile]

The PRV discharge pipe should only be soldered or joined with compression fittings.

Some of the plastic push fit may not be able to withstand the 120 C temperatures which might be present in a fault condition.

 

[FiremanT]

The OP did not even mention push fit

 

[Madrab]

Fire away OP, no reason not to.

 

[ianmcd]

as said already no reason why not, try if you can though to have a downward run on the pipe through the wall as if the PRV passes in cold weather you can get ice forming in there and that is not a good thing if the boiler actually needs to discharge, when you turn the discharge point back to the wall , leave a gap of at least 1 x the diameter of the discharge pipe, between the end of the pipe and the wall surface

 

[Steelmasons]

Some of the plastic push fit may not be able to withstand the 120 C temperatures which might be present in a fault condition.

120c???..surely the water would turn to steam when released from PRV?
Don't confuse a PRV with that of a TPRV.
Have you ever encountered a domestic boiler reaching temps of 120c before the thermostats operate?

 

[ianmcd]

The PRV discharge pipe should only be soldered or joined with compression fittings.

Some of the plastic push fit may not be able to withstand the 120 C temperatures which might be present in a fault condition.

Just about sums up how much you havent a clue about regarding how boilers work

 

[PullerGas]

Hi All,

SUMMARY: Can I use a copper compression fitting on the expansion discharge pipe of a gas boiler?

I have a a Vaillant system boiler, about 5 years old. I need to change the route the expansion relief/discharge pipe takes.

I know that the run must be in continuous copper pipe, the end of the pipe must be visible, shortest run with slope away from boiler and it must terminate in a safe place where people can't be scalded. I'll be going straight through the wall the boiler is mounted on and terminating outside with the usual 180 degree bend back into the wall.

Is there any reason why I can't use a compression fitting to make the join between the vertical pipe connected to the boiler and the horizontal run? I know it is normal to solder, but it's a bit cramped in there and I don't fancy wielding my blow torch so close to the boiler ... I assume this is ok as the final fitting to the boiler itself is just supplied as a 15mm compression?

Many thanks!

James, Ideal Logic boilers require a compression fitting on the blow-off, it's in their manufacturers installation instructions. Do they supply it with all the other valves etc for the boiler connections, of course not they're from Hull Yorkshire, as tight as a duck's arze!! Good boilers though.
Happy to help.

 

[Dan Robinson]

The PRV discharge pipe should only be soldered or joined with compression fittings.

Some of the plastic push fit may not be able to withstand the 120 C temperatures which might be present in a fault condition.

I thought you advocated actually reading what the OP writes in their posts?

 

[kidgreen61]

You may have trouble sourcing a copper comp fitting, but by all means use a brass one.
I'd be interested to see water exiting a modern boiler at 120C

 

[James Carmichael]

Thanks all for the advice and tips.
@kidgreen61 - Yes, indeed. I meant brass. It would be very hard, under standard conditions of pressure, to have liquid water at 120 degrees escape from any boiler, modern or otherwise.
@Agile - no intention of using push fit or plastic pipe. As per my original post, I'm using copper pipe and my only option was [brass] compression or solder.

Anyway, thanks all - appreciated