Boiler Making Loud Banging Noise

economiser wrote:

If you have a header tank and cannot find ad drain point you could simply bale some water out into a bucket. You don't have to drain the tank completely, just enough to get the descaler in.

Not really because the descaler is concentrated and is only one litre. If you just pour it into the header tank, it will most probably still be there next year unless water is drained off to ensure that it actually circulates around the system though the boiler.

I have the same problem, BG did try putting stuff into the system but didn't work for me. When we fitted a new radiator, OH had to go out and buy what BG had put in to replace it and it was £50! They had left the paperwork with me with the name, can't remember now.
I dread winter as it can happen twice a day and scares my kids to death as it sounds like thunder in the loft!
I can always tell when mine is going to go as one radiator gets really hot and you can hear a dripping noise in the pipes.
The system usually shuts itself off with the 'overheat' thingy..
BG been out loads of times now but they have said unless they are there when it happens thay can't really see anything wrong.
I have found them to be really good and they do try different things.

robodan wrote:

can anyone submit a pic of what to look for for a drain tap? also if i drain it, how do i top it up? is it a job for a complete novice like me?

Does anyone know if BG will treat this under their agreement?

This is a typical drain c0ck:



They should be fitted underneath downstairs rads or at the lowest point of the system.

To drain the header tank, turn of cold water supply, attach a hose to the drain c0ck and open, fill up a couple of buckets and then put the descaler into the header tank. Turn the water on again and bleed the rads to get any air out. Leave it to do it's stuff while it circulates around the system and through the boiler.

British Gas are more likely to tell you that you need a new boiler because they get commission on sales!

:mad:

PS I wasn't allowed to type c0ck!

I have a similar problem, with what I assume to be air bubbles. These cause loud noises for a few seconds every now and then. But how can I ensure the cleaner goes into the indirect pipe circuit for my hot water system and stays there? Second, how do you 'bleed' such a system of air? Also, should you ensure a chemical is left in the indirect circuit to prevent the return of corrosion?

I have no central heating - just hot water heating. There's a header tank in the loft and an 'indirect' copper water cylinder in the airing cupboard on the first floor. A burner on the ground floor heats water and sends it round an 'indirect' coil in the middle of the cylinder. It's a very common arrangement.

If the indirect circuit is drained, it gets topped up from the main cylinder. Perhaps it has a one-way valve. How else would they stop any chemicals (in the indirect circuit) going into the main water in the tank?

Regards
George

espresso wrote:

An indirect hot water tank has a coil inside to heat the contents of the tank which is kept entirely separate from the boiler circuit. You should be able to follow the pipework to see how it works and find a bleed valve. The Sentinel x200 is supposed to be left in the system.

Thank you for your input. But I'm still confused. The indirect circuit can't be entirely separate from the main part of the tank (the water which is used). I say that because I drained the indirect circuit once or twice, and all other parts of the system too. Then when water flowed back into the system it refilled the indirect circuit os there is at least a one-way link.

I'm fairly certain I caused the problems in the first place by draining the system of chemicals and then not replacing them afterwards.

Does anyone know if there is a one-way valve, please?

Regards
George