Newish System operating fine......but loud banging....

Joined
4 Dec 2012
Messages
8
Reaction score
0
Location
Berkshire
Country
United Kingdom
Hi,

Just to introduce myself, i'm a new member, but have been hovering the forum for tips and hints for years....but now I need some specific help. I have searched numerous times to find an answer to this, but no joy. I hope one of you clever chaps can assist. :eek:

Anyway, I have a loud banging coming from my heating system. It is quite a loud 'bang', which happens intermittantly whilst the boiler is running. It seems to be eminating from the cold fill pipe in the airing cupboard, and is usually accompanied with a whooshing sound. There is also a 'bubbling/gurgling' noise which can be heard from the pump around the same time. (almost as if aerated water is passing through).

The heating system is a traditional open vented Y plan system, with a Baxi Solo 15HE boiler in the kitchen. In the airing cupboard on the first floor I have a Grundfos 15-50 pump, Drayton mid position valve and hot water cylinder. The F&E tank is located in the loft.

The boiler, pump, valve and cylinder were all installed in March 2010 and all appear to be working fine. By this I mean the boiler has no fault lights and ignites, runs fine and the flow pipe gets very hot. The pump is spinning freely (setting 2), and the valve moves across and does what it should. (i.e. heating, dhw or both). I have been up in the loft watching the F&E tank during this scenario, and there is no bubbles from the fill pipe, or anything come out of the expansion pipe. Its all quite still up there, although I did notice there is quite a bit of crud in the bottom of the tank. Following advice on the forum I have also isolated the cold water supply to the tank and let water out of the system, and the level has dropped. The tank then refils satisfactorily, which I assume indicates the pipe is not blocked.

The house is a 1980's build 2 bed detatched, and I feel as though the boiler is a little undersized. Therefore during recent colder weather I have had to turn the boiler right up to nearly maximum on the temp adjustment screw to keep the house warm. (This is giving me 60deg C surface temp on the rads, which is fine for us).

However, having the temperature turned up seems to have caused the banging to get quite a bit worse. So much so it wakes us up in the morning and distubs us when watching TV on an evening.

I have bled every rad, at least 10 or 15 times, and there is no air. I have bled the pump around 10 times and again, there is no air. The thumb screw valve in the airing cupboard does seem to collect air which I release every few days, but bleeding this doesn't stop the banging.

Any ideas of what else to check....? My gut feeling based on the noises i hear is gas escaping up the fill or expansion pipe but I dont know how to test for this...?

Thanks in advance!

Matt
 
Sponsored Links
tell us about the corrosion inhibitor

Are you in a hard-water area?

tie up the ball valve float for a couple of days and see is the level drops. How deep is it?
 
Thanks for your reply John.

The system was filled and commissioned prior to me owning the house. I have certification from the installer, which itemises the use of inhibitor in the system! Further to this, there is an empty bottle or "Sentinal" something or other next to the tank in the loft. However, I have never drained the system fully or topped this up.

I recently tested the PH levels of our water, and it was slap back in the middle of the tester card. i.e. Medium hardness.

I will tie the ball valve up tomorrow evening once I get my ladder back which I use to get into the loft and report back. What should a drop in level show? The boiler causing the circulatory fluid to evaporate?
 
if you see a drop in 2 days, it means a leak. Unless it is over-full, in which case it may overflow when hot and expanded.

A leak accelerates corrosion and loses the inhibitor which is then diluted by the top-up water. The addition of fresh water also accelerates limescale. Is your kettle as clean as mine?
View media item 4336
The Sentinel bottle is probably X100
 
Sponsored Links
I will do a test of the F&E tank over a couple of days, thanks.

As for the kettle....we have more of a light coating of limescale on the base of our 6 month old kettle but nothing serious....
 
Hi,

Just to update the post with my findings and look for further help.

I tied up the F&E ball cock and noticed no drop in level at all. It is also not over filled.

Today I drained the system and refilled the system, including a litre of X100, which went fine. The water was a little dark but not much in the way of sludge or debris came out (I ran the hose pipe into a clear vessel so I could inspect it).

Anyway system is all topped up and boiler running fine, but I've still got the banging as before. It really seems to be worst during warm up phase.

Any ideas? Perhaps try adding some X200?
 

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