Possible leak in central heating system'

[JSM]

Hello Good Guys Who Help People,

I moved into a new build bungalow nine years ago. It is quite big - 4 bedrooms, 2 public rooms, kitchen, utility and 2 bathrooms - so there is a lot of plastic piping. I have a combi boiler and I think it is called a pressurised, sealed system.

From the time I moved in I suspected at least a 'weep' in the system. I normally had to top up the boiler 2/3/4 times a year. I couldn't top up the inhibitor because the plumber didn't know what type he put in and I know different types should not be mixed.

However, over the past couple of days I have had to top up daily which suggests, I think, a leak. Prior to this the boiler had begun behaving oddly with the pressure going higher than usual when the heating was on though not over the limit.

I'm guessing that I am going to have to lift floorboards, etc. and start looking (or at least a plumber will).

1. From what I have described, does anyone think it is worth my while trying to put in some of that 'sealant' stuff similar to what is put in car radiators?

2. After nine years, is it safe to put new inhibitor in?

I would be most grateful for any advice anyone can offer.

Thank you.

 

[ianmcd]

I dont think you have a leak, it sounds as though your boilers expansion vessel has failed, if you look in the wiki on here it will give you instructions of how to re-pressurise it, you MUST follow all the steps especially the one about leaving a drain point open while re-pressurising,

Do not use leak sealer it doesnt work and could damage your boiler.

Once your problems are sorted add sentinell x100 inhibitor it wont react with anything else, there are others that are safe to mix

if you go back to topping up 3-4 times a year I wouldnt worry too much about that, if you do have a leak you will find it by luck more than anything else, possibly just a small weep at a radiator valve

 

[JSM]

Ian,

That strikes me as being exceptionally helpful. Thanks very much for taking the trouble to reply. If I may trouble you with a three extra questions:

1. I am due a boiler service now from British Gas. Do you think the expansion vessel is something that their engineer would do when he/she visited i.e. is it just a small job or should I get a plumber in to do it. (I'm pretty hopeless).

2. If it is a problem with the expansion vessel where is the water that I introduce to the system disappearing to?

3. If there is a weep it could just as likely be under the floorboards. Would this be worth bothering with?

Many thanks in anticipation of your very kind further assistance.

Jim

 

[Dextraneous]

If the expansion vessel is not pressurised, then since water expands as it is heated, it will quite probably have "escaped" through the pressure release valve. These have a habit of not closing properly and thus the system will continue to lose water. As you're on a BG service contract, you might as well give them a call and let them sort it out.

 

[ianmcd]

Why are you getting British gas to service your boiler ?

Do you have a maintenance contract with them ? if you do then call them as pressure loss is covered and let them fix it.

Unfortunately if you are just calling them to service your boiler they call it an annual safety check and they wont service it if it is working ok and almost certainly wont check the expansion vessel, depending on the engineer they might check it if you ask them to.

If you dont have a BG contract get a local independent with a good reputation to do it or call the boilers manufacturer and get them to do it.

When the expansion vessel fails it lifts the pressure releif valve off its seating as a safety device and the water is released to outside your house, when the water cools the pressure drops as you have lost some of the volume so you have to re -pressurise

As already said if go back to topping up every three or four months I wouldnt worry about that too much and certainly wouldnt be lifting floorboards looking for a leak, if you have a tiny weep it will become apparent over time or it will get worse and you will see it, it might even seal itself

 

[JSM]

Thanks Dextraneous and thanks even more so, Ian. Where would the World be without decent guys like you?

The contract I have with British Gas is one of these £12 per month jobs, with one visit per year so it sounds as though I may be covered for this work.

So my plan is:

1. Book a visit from British Gas.

2. Keep topping up meantime - this hopefully will do no harm for a couple of weeks(?)

3. Once the problem is fixed, I'll get a plumber to add Sentinell x100 inhibitor.

Any flaws with that gents?

Kind regards,

Jim

 

[ianmcd]

Yes thats the way to go Jim, if you dont want to pay a plumber to add the inhibitor look at Fernox express inhibitor, you can put this in via your filling loop its very easy to use and you can mix it with any existing inhibitor that might still be in your system.

http://www.ebay.co.uk/itm/Fernox-F1...arden_Hearing_Cooling_Air&hash=item20dfd7cf36

 

[JSM]

Thank you, Ian! I'm more grateful than you will ever know. I will enjoy the rest of my weekend now.

Thanks again!

Jim

 

[Dextraneous]

Chances are that if you call up BG, you'll get one round within a couple of days.

 

[JSM]

Thanks Dextraneous. British Gas coming in just a few days.