Gas Boiler Water Pressure Requiring Daily Top Up

I've recently moved into a new house which has gas central heating. When we moved in the gas boiler pressure was at 0. We filled the water system from the valve in the hotpress and bled the radiators. The boiler pressure was then at 1.5 when cold. Problem is - the water pressure on the boiler drops from 1.5 to 0.5 daily even though we only have the heating on for approx 2 hours per evening. So we are constantly having to top up from the hotpress. Also one of the radiators doesn't work - I'm not sure if this is related. Even the feed pipe into this radiator doesn't heat up. I've read the other posts but my situation seems more extreme. Not sure if I need a gas man or a plumber or do I just continue to top up daily. Help!

Hi,

Welcome to AAM.

As its a new house have you tried contacting the builder to get them to investigate the problems?

Hi SueEllen. When I said new - I actually meant it is new to us. It's a second hand apartment. The development is about 7 years old. We are in an own door ground floor apartment under a duplex apartment. So it's a three floor development. It doesn't have any internal communal areas so I don't think it's an issue for the management company. All the floors are cement so I'm not sure where to even start looking for a leak. All ideas gratefully accepted!

Get a hold of a plumber, sooner rather than later. Chances are you have a leaking pipe which is causing the pressure to drop.
The rad not working might just be due to a closed value. Are you able to turn the value on the rad itself, sometimes the pipe joining the rad is not straight and will not operate correctly, this is a small job which could be done at the same time as the boiler pressure job.
Have you tried asking the last owners, maybe there is some history there, and a word with them might save your Plumber alot of time.

Tried contacting the previous owner but his phone just rings out - doesn't even go to voicemail. He's based in the UK so I've no other way of chasing him down. I dread to think what kind of money this is going to cost. It's concrete floors throughout so it looks like it could be a big job - especially seeing as there's no evidence of where the leak could be. I don't want to have the whole floor dug up on a wild goose-chase. This happened us in a previous rented accommodation and the plumbers did a disappearing act having dug up the floor in the kitchen and sitting room and without fixing the leak.

would home insurance cover some of the cost?

The system you are describing is a closed system - right? Therefore decreases in water pressure indictate a leak somewhere in the system. Have you tried tightening the connections to all the radiatiors in your house. Small leaks in a rad might well be difficult to pick up as the water tends to evaporate when the rad is hot. All you will see happening is a gradual decrease in water pressure. If you had such a leak on each of your rads it could add up to a big drop in pressure. The non functioning rad is definitely suspicious though - the fact the feed pipe is cold would indicate to me that it is disconnected back at the manifold - this may in turn be the source of your leak. You should really get a plumber to check it out - should cost no more than a few hundred euro max. to fix.

I had a similar problem last year with my gas combi boiler. I got a plumber in to look at it and he said I'd need to get a part replaced. As the boiler was only 2 years old, I wasn't exactly happy, but I got in contact with another plumber who was able to fix instead of replacing the part (sorry to be so vague about this "part", but I'm not good on plumbing issues!). It didn't cost much, and solved my problem.

The part may have been the pressure release valve, sometimes it leaks.
Is it possible the water is leaking out this valve. It should lead to a small pipe from the boiler to the outside and is designed to relieve pressure out of the boiler if it goes too high.
The water has to go somewhere, either a leak under the concrete or this valve is allowing the water out.
Also the water should be topped up to 1 bar or less.
What happens is that as the water heats up , the pressure increases. There should be a red pressure vessel somewhere whose job is to absorb that pressure. If it doesn't then the pressure goes above 3 bar and water shoots out the release valve. first thing is to see if water is coming out of the release valve.

Yes beldin, that was part of the problem, water was dripping out of a pipe outside (and still does occassionally). There was something else though, the plumber had to pump some part of the boiler, the part the other guy said needed replacing. For the life of me, I can't remember what it was.

He pumped up the pressure vessel. Basically like a tyre tube inside which has to be pumped up. Then when the water expands it crushes this tyre. Air compresses while water doesn't.

I had the same problem as described - the cause was the pressure vessel it was old & leaking - it is located next to the boiler & I noticed that a few minutes after switching on the boiler water started dripping from the vessel, for some reason the pressure release valve also leaked, I replaced the Pressure vessel Cost €25
it was a reasonable straightforward job, If the area near the pressure vessel is damp & wet then this is potentially your problem also.

Thanks for all the responses! Glad to hear I may not need to bring in the bulldozers just yet! I've just noticed that the chipboard "floor" of the hotpress appears to have a small damp patch where 3 pipes drops vertically through it. One of the pipes has a round red twisty wheel/valve type thing. Still can't see where the water came from but it's at least given me some comfort that the problem is overground rather than underground! Many thanks.