Central heating system loses pressure every day

Joined
21 Feb 2009
Messages
1
Reaction score
0
Country
United Kingdom
Hi,
I have read all the post on central heating systems losing pressure,but cannot get a solution to my problem.
I have an Alpha CD24S boiler feed 16 rads. I live in a bungalow .Hot water is supplied by a separate boiler.
The system is three years old and has been installed by a well established, reputable CH company.

Over the past two months, the CH system has been loosing pressure. Initially, I needed to re-pressurise every three days, then two days. Now it is every single day. I estimate taht it takes about 15 seconds to pressurise, which I guess is equivalaent to about atwo litres of water.

The system works OK during the day. Every morning the pressure has dropped below the point at which the boiler will fire. I have repeatedly checked all visible pipework and joints for leaks, with nothing apparent, both with the heating on and off. The only pipes that are not visible is the run in the loft from the boilers to the bedrooms, a small run behind skirting board and another small run behind tiles in the bathroom.

If I did have a leak in the pipes that are not visible, I am sure that it would be revealed by now by damp patches. My CH installer has made numerous vistis, without solving the problem.

Yesterday morning I re-pressurised the system as I have done every morning for the past two weeks. However, I turned off the CH boiler. The pressure on the gauge on the boiler has now not moved for 36 hours.
Does this suggest that the problem is in the CH boiler itself, as if there was a leak in the pipework, surely the pressure would have dropped by now ? Or when I pressurise the system, without turning the boiler on, am I not actually pressurising the pipework this time, only the boiler.

One other thing I have noticed is that there is a drain from the boiler that discharges to the outside gulley. With the CH boiler on this discharges over two litres per day. Is this just condensate or could this be the source of where the water is going that I continually have to top up.

One final question, if it is a leak on the system, approximately how much does it cost to have an organisation with thermal imaging or other means come in to locate a leak ?
 
Sponsored Links
I had exactly the same problem, the man changed the 2 tanks inside the boiler and 2 other tiny parts, sorry I can't help anymore, but it took 7 visits to solve,over weeks, I think the pressurised tank was the problem and the other little values were just changed to ensure it was all new, sure someone on here will help you though
 
Firstly check that the pressure relief valve is not discharging. You should have a copper pipe outside. If you're not sure if it's discharging loosely tie a plastic bag over it.

If it is discharging it's either a faulty valve or problems with the pressure vessel. To check the vessel re pressurise the system and then turn on. The pressure should rise slightly but not dramatically. If it rises dramatically there is likely to be a problem with the vessel.

If there is no discharge from the discharge pipework then you have a leak. If there is no sign of it, it could be the heat exchanger leaking into the condensate sump.

Mike
 
Sponsored Links
I think swbjackson as summed it up the blow off valve is cheap & the bags the best check but if you dont sort it all that new water as oxygen in it & will rust your system so get it fixed & if you getting a plumber out buy some inhibitor to put in after fixing .
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Back
Top