problem with boiler

[luckydebs1]

I have a heat line boiler which is leaking water from the outside pipe . I have had two repairs done recently but still having the same problem . The last plumber said that the pressure was faulty and replaced a part , it was ok for 3 days . The water has again started to gush out of the pipe. It has caused damage to the exterior wall and the water is starting to seep through the door frame . Any help would be greatly appreciated ?

[buildersmate]

How much water has come out in total. 'Gushing water' doesn't easily collarate to the plumbers assertion that the pressure valve was at fault - if this outlet is the pressure relief valve outlet, it wouldn't gush lots of water - just a few litres of hot water.

[luckydebs1]

It is a continuous flow of water . It is as though you have just turned a tap on . Sometimes it can gush and it was actually going into next doors yard and wetting all of their garden furniture !

[buildersmate]

Is it cold water? - if so it must be from an overflow pipe from a cold water tank perhaps?
If you haven't got a cold water tank, is it hot water?, in which case, it points to the pressure relief valve on the hot water system. This would normally be a 6 bar pressure relief, and would only vent under fault conditions. The mains cold water pressure coming into the house should be limited to about 3 bars, so this pressure could never force against a 6 bar valve - except in fault conditions which you sat you don't have. Maybe ABer Gasman can help.

[gasman]

Hi, luckydebs1,
buildersmate suggests a blow off at 6 bar this is only true on the older boilers, So if your boiler is not more than say ten years old and is a sealed system or combi boiler the safety valve is set to blow at three Bar. If this is the case and you have a sealed heating boiler installed then.

1. first make sure the filling loop is not connected and has been left turned on. or that it is faulty and passing water when it should be off. either case the filling loop should never be left in place. This is a breach of water bylaws and regs and could lead to possible cross contamination of the drinking water.

2. If all is OK with the filling loop then you need to accertain that the expansion vessel diagprahm has not been punctured so put a car tyre pressure guage on it and see if the reading is that as stated on its label. if it is low and doesnt rise when pumped up, then the expansion vessel diaghpram has failed and will make the saftey valve blow off. The whole unit must be exchanged as they are a sealed unit.

3. If the expansion vessel is ok then all that is left is the safety valve. You will have to check the pressure of the system to accertain this, if it is lower than three bar and it still blows off then it is faulty and needs replacing.
( i would suspect this is what your plumber has changed allready, but maybe he didnt think to find the cure rather than just stick on a new part )

[BessBarrie]

I had this problem this week when plumber fitted new bathroom. He told me the overflow pipe gushing water down the outside wall (and into the basement flat!) wasn't mine. When a neighbour knocked on my door at 3am I turned off all valves to the boiler and it stopped. The boiler pressure then dropped to zero so no hot water or heating! Anyway, it transpired the filling loop had been left on and this was causing the overflow outside. Once I realised this I had to re-set the pressure by gently releasing the filling loop until just over 1 bar on the pressure guage. The taps are all tightly closed now. Not sure if this helps?

[BessBarrie]

This webpage helped me resolve the filling loop, boiler pressure and stopped the water gushing outside!
http://www.ultimatehandyman.co.uk/TOPPING_UP_A _COMBI_BOILER.htm