Boiler losing pressure but cant find a leak.

Sandwich84

I'm worried I may have to have an expensive visit from the plumber in the not too distant future...

My combi boiler seems to be slowly losing pressure, at rate of about 10th of a bar every two days. I can't see any leaks (most of the pipes are exposed and those that aren't are in the ceiling where a leak like this would become obvious pretty quick). The overflow from the boiler isn't dripping either. I have noticed though that when someone uses the hot water the pressure gauge fluctuates a little bit.

Does anyone with some experience have any ideas what this could be?

bertie200

we had this same problem a few years ago, plumber couldn't find any leak, but said it was down to us to find the leak, 2 subsequent other plumbers said the same thing.

we had no option but to lift all our wood and ceramic tiled floors, we ended up lifting the lot, the very last one was the bathroom as it had the most expensive flooring and lo and behold there was a miniscule drip coming down from one of the radiators.

it was a very expensive nightmare and should have been noticed by the plumbers or us, but it was so slow that it wasn't obvious until the floor was lifted and we found a very small wet patch.

keep checking all the nuts on the radiators, as very small leaks can be very hard to show up.

good luck!

elsien

I was going to say something similar - my boiler was losing pressure at what seemed to be an alarming rate but I couldn't spot where from so I was starting to panic and scour the ceilings for damp patches. It turned out to be a nut on a radiator that needed tightening. Because the radiator was permanently on low, the water was evaporating before it made a damp patch on the carpet. I only spotted in when I noticed discolouration on the pipe work where the leak had left a dirty trail down the pipe.

alanobrien

As a starting point. If you know what your doing switch off the boiler overnight then lock of the flow and return valves Check the pressure then check it again in the morning. That will tell you if the boiler is loosing pressure or if the problem is elsewhere in the system.