Boiler drops from 1.2 to 0 in an hour!

[tonysab]

Thanks.

The other odd thing was the other day I noticed the boiler was dripping from underneath. Not a great deal but it was dripping. This may have been following the test we did with the engineer where we isolated the flow and return valves - when he went to open one of them back up he had trouble turning it but eventually did it - not sure whether this would cause the dripping?

 

[tonybhoy]

I wouldn't worry too much about the odd drip here and there but what you've described is something far more serious and since you've found no evidence of leaks on the pipe-work under the floor of the house then it can only be the boiler that is causing the pressure to drop so frequently.

On those Vokeras the problem was sometimes obvious (flooding from the boiler) or not so obvious- water pressure dropping rapidly and constant topping up over a short period of time (couple of hours max).

Topping up a boiler up to ten times a day is a lot of water to lose and that water has to be going somewhere.

 

[tonysab]

This is very strange - after not having to top the boiler up for the past 6 weeks, tonight I noticed that the radiators upstairs were lukewarm whilst the ones downstairs were hot, so I bled the ones upstairs, 4 in total, and whilst bleeding the last one, as the air was coming out it suddenly stopped and when I came back downstairs the pressure gauge was showing empty!!!!!! I refilled again and an hour or so later it was completely empty again!! What on earth is going on - of course the sealant put into the system 6 weeks ago could have suddenly broken but it seems a bit of a coincidence that bleeding the radiators seems to have caused this?

 

[David937]

Bleeding rads causes the pressure to drop but after you refilled it shouldn't go back down.

 

[Agile]

One thing though that the engineer said that really confused me, was that he had recently fixed a similar leak in another house where the pressure was dropping so fast you could almost see the needle on the gauge drop before your eyes - but when he eventually found the leak, beneath the living room floor - it was just a steady drip, drip, drip - not gushing out as I would have imagined? Does this sound right?

Thats what happens when the expansion vessel has hardly any air in it!

Tony

 

[Gastel]

Have you checked the draincock (if you have one) outside or next probable cause is manifold.