Dripping overflow T&P valve or expansion vessel?

[Harj]

Hi

I have a megaflo CL170 water cylinder, I noticed an intermittent drippingfrom the overflow pipe outside, I thought it could be to do with the air gap,so followed the instructions on the side to replenish it, however after havingdone this twice I noticed that the dripping had become even more constant,although it has stopped now.

I’m not sure whether the T&P valve is leaking on the cylinder or thedrip could be from the expansion vessel run off which also feeds into the sametundish. The expansion vessel I assume is for the central heating, the pressurereading on that is currently 1 bar. Presumably if the dripping water is hot itmust be the T&P value, if it’s cold it must be the expansion vessel.

Any thoughts?

 

[unguided1]

Hi Harj
you have obviosley followed the instructions properly about recharging the air gap, If the T&P is still letting by then I suggest it is time to get a G3 registerd plumber in to find out what the problem is, as the problem could be serious and unvented cylinders are not to be messed about with

 

[Gray0689]

If the heating staying at 1 bar then it is from cylinder needs checking out and propably new t&p relief valve or new safey valve if you have the required expansion air bubble
Also if you where not aware unvented cylinders should be serviced every year by a qualified person

 

[Harj]

Thanks for the replies

The dripping has stopped, but only seems to start when the boiler comes on for hot water/heating. It's not constant either, I will keep an eye on it, I contacted a plumber who quoted £80 to replace the T&P.

I doubt the cylinder has ever been serviced, its about 7 years old.

What the usual life on a T&P valve?

 

[Gray0689]

hard to say but id get it changed and serviced

 

[Harj]

OK, on another note should the heating system be pressured to 1 bar? Just wanted to know if there was a standard setting I should use for a 4 bedroom house.

 

[tamz]

Not tonight. Phone me tomorrow

 

[Gray0689]

1 to 1 1/2 is fine

 

[Harj]

OK thanks, could the leak with the T&P value explain why the upstairs shower (one floor above the cylinder) has poor hot water flow, even after resetting the air gap?

 

[AWheating]

not really, check filters in shower and when you have the cylinder serviced make sure you have the pressure reducing valve and strainer checked to make sure hot water flow and pressure are not being effected.

could also just be poor water pressure? or non balanced hot and cold at shower maybe?