heater burst a pipe

pappajohn

LIFE MEMBER
Aug 26, 2007
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Can't see a burst pipe but it looks like the pressure relief valve (the red thing) has opened and dumped water through the (clear) outlet pipe which the converters haven't bothered putting through the floor to the outside.
Possibly the boiler thermostat has failed and its overheated

No idea what that is at the top of the clear pipe, looks like some kind of sleeve over the pipe which has started to come apart. .
 
Last edited:
OP
M
Jun 3, 2018
52
22
The clear pipe is the burst pipe were hot water was coming from.
That clear pipe then goes to a hole in the floor next to the grated hole.
What would cause the pressure if that is the case.
 
Sep 1, 2018
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Strathaven
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Dethleffs A7877-2
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Apprentice
Not to sure what I’m seeing BUT I think papajohn is close , if the red thing is a prv ( pressure relief valve ) and the clear pipe is a discharge pipe, then I would say the prv has opened trying to discharge the water through the clear discharge pipe to the outside ( which should be open ended ) I think the clear pipe is likely to be blocked or blanked off , if the prv was passing , someone may have blanked it to stop the loss of fluid , the clear discharge pipe is not strong enough to hold the pressure so has burst

Just an old heating engineer/ plumbers thoughts lol
 

pappajohn

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Aug 26, 2007
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OK, it isn't very clear in the photo as the edges don't look thick enough for the pipe and I can't see where it exits through the floor.
The only thing that could cause that is the boiler safety valve opening which SHOULD dump water underneath but to burst the pipe it has to be blocked, probably underneath from general road crud.
The safety valve will only open if the boiler overheats and the pressure exceeds the valves preset opening pressure.
The boiler will only overheat if the internal stat has failed and can't shut the boiler off.
 
Sep 1, 2018
242
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Strathaven
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Dethleffs A7877-2
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Apprentice
Don’t look like any prv I’m use to ( but still could be) it looks like a T ( branch) , where does the clear pipe go to when it goes back into the van
 
Sep 1, 2018
242
224
Strathaven
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Dethleffs A7877-2
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Apprentice
Try putting a thin screwdriver through the top opening of the red tee
To see if hits is any type of valve , if the screwdriver passes through the tee then it isn’t a prv but just a tee
 
Sep 1, 2018
242
224
Strathaven
MH
Dethleffs A7877-2
Exp
Apprentice
That could be a valve that opens when the temperature drops below (usually 3deg) to empty the heater and save it from frost damage
 
Aug 6, 2013
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Kendal, Cumbria
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So is this a pressure relief valve?
Yes - the boiler is effectively a sealed vessel with the hot taps closed on the outlet and a non-return valve on the inlet. When the boiler heats up, the water inside expands. Most of the time the pipework is flexible enough to accommodate the expansion but ultimately the pressure relief valve releases a small amount of water. It should go via the clear pipe to the underside of the van. The clear pipe is what it appears to be - just a simple piece of pipe open at the end under the floor.

Edit: Don't poke it with anything. It is not a T :).
 

pappajohn

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Aug 26, 2007
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It looks like it comes into the underside of this valve, whatever that is. I assumed it was a drain point
Whether it's a prv or not, that clear pipe is going nowhere.
It's coming off the prv/elbow/tee, through the floor and back up to the dump valve which by default is closed so the clear pipe is blocked.

How will the dump valve work? It can't empty the boiler as intended as the outlet goes back to the boiler.
How do you drain down in winter?

Whoever installed this wants their arse kicking until their nose bleeds.
 
OP
M
Jun 3, 2018
52
22
Should that clear pipe that comes out of the floor therefore have been cut on installation allowing one to empty and one to relieve any pressure.
I’ve never emptied it before as it’s new to me.
 
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