Boiler Losing Pressure - I can see dripping from a valve

[ianmcd]

As @CBW correctly says, check the direction of the motorised valve, the body has an arrow on it to show the direction, if fitted the wrong way round it can make a clunk when closing

 

[hoodlum59]

Quite possibly CBW. This was also replaced by BG a few months ago (in fact they did it twice as the original work didn't stay working beyond their original visit). The valve was getting stuck open. That appeared to have been resolved as it no longer stays open after the heating runs.

I have just manually opened the valve and the boiler started to run. I dont recall this happening in the past when I manually opened the valve. Is this right? I did it several times and yes, the loud bang does indeed appear to be coming from here, rather than the boiler.

I also observed the isolator tap on one side was only about halfway open. I have fully opened it now but the bang still happens.

 

[ianmcd]

Post a pic of the valve and the pipes it is on

 

[hoodlum59]

 

[hoodlum59]

I have checked and cannot see any directional arrows on the brassware, either on the top or underneath. I have provided a picture of the valve as well as the motor, both of which were replaced when BG visited around March / April time. The heating obviously hasn't been on much until recently when I began to notice the banging noise.

ps, that drip is as a result of opening the tap on the right which was only half open at best. I expect it will stop itself but have put a tray underneath for now!

 

[oldbuffer]

1. Flow should be left to right per your photograph. In to Port A, out from Port B.
2. The drip is probably from the gland nut on the gate valve. Easy enough to stop. Look up "weeping gland nut" or similar on the internet.
3. The gate valve you opened may have been a balancing valve for the hot water system, in which case it should not be fully open.

 

[hoodlum59]

Hi - I can confirm that the flow does indeed go from left to right (the pipes are labelled!)

The drip has stopped already and I have ran the boiler at least 5 or 6 times since yesterdays message so I am happy that its not leaking under hot or cold pipe conditions.

I think (correct me if I am wrong) the balancing valve is the little white dial in the picture below? I've always had all taps other than this one fully opened.

I am still getting the loud bang once the heating finishes. It is definitely coming from the valve pipework. What continues to puzzle me is that by opening the manual lever on the valve, the boiler ignites. I am 95% sure this was not the case in the past - I have notes from the original installation saying to manually open this whenever I need to drain the system (new rads for example) so I am convinced it didn't used to fire when this valve was manually opened. Should it fire when this is opened manually?

I have attached a better picture showing the rest of the pipework around the valve

Thanks as always!

 

[oldbuffer]

1. You are right. The gate valve is there to enable the water to be isolate in order to change the motorised valve. It is not for balancing.
2. The valve at the left of your latest photograph does look like an automatic bypass valve.
3. The drip is likely to be fixable as previously advised.
4. There is a microswitch inside the valve. When the valve operates at the direction of the thermostat, it moves to the open position. As it gets to the end of this movement it closes the microswitch and signals the boiler to fire. Normally the manual lever doesn't move the mechanism far enough to affect the microswitch. Sounds as if yours is doing so however. Doesn't really matter.

 

[hoodlum59]

Final update on this one for anyone else wondering / who looks at this at a later time - the valve was indeed the wrong way round. BG came today and immediately said it was likely to be that. A quick change and it was all resolved. Picture attached!

Needless to say there was no charge involved. The previous person who came was a contractor for BG, he had actually visited twice for the same valve issue. Still didn't get it right it seems. We could go on all day about poor workmanship - its the same in all jobs, not limited to trade or any other job type in particular. I've long held the opinion that 10% of people are good at their jobs, the rest just get by!

Thanks for all those who have commented and given me insight / info

 

[Deleted member 267285]

Thanks for updating, not everyone does. Glad you’ve got it sorted out