Swishing water noises

[corkybrandy]

Can somebody please point me in the right direction ? We have a 13yr old combi-boiler system, Ideal Classic fanned flue boiler. Over the last 2 yrs we have had British Gas out a number of times to fix our system going off completely. Each time it has taken min of 4 visits and part replacements each time - twice the water pump has been replaced. About 12 months ago the boiler made a banging noise and switched off. It was fixed by a new water pump (!) and other parts and seemed to work OK. Then after the service some 6mths later we started developing noises that
were swishing noises in the pipes (ie it sounded like a car driving through a wet road outside the house !).

Eventually some 8 weeks ago after the noises were accompanied by louder grumblings in the boiler the boiler banged to a grinding halt,follow ed by the swish then ending. Over 2 weeks they came and said it was overheating and visit 1. reset the cut off in the boiler housing. visit 2. replaced a part within the boiler. visit 3. replaced water pump & a part in the airing cupboard. visit 4. replaced control panel, some part on hot water tank and another part upstairs. visit 5. couldn't help as laptop was broke ! visit 6. replaced many new parts including the bit housing the cut off/reset swich. Only at that point did it run for more than 2hrs without swish, bang & stop.

Yesterday the swishing noises have returned as loud as ever so we have turned off the central heating before it does it itself. As I have little faith in British Gas I was wondering if some proper qualified central heating experts think before I get them out again. Is a "chemical flush"(?!) likely to help or has anyone an idea why this swishing noise isn't triggering the fault to them - not one ! ? All opinions gratefully received.

 

[gas4you]

I'm a bit confused, have you actually got a classic combi, or an ideal classic with a hot water cylinder. From your description it sounds as though it is a classic with hot water cylinder in the airing cupboard especially if BG have replaced bits in the airing cupbard.

Is it an open vent system with a tank in the loft, or a classic with a system conversion, in which case you will have to fill it from the mains via a filling loop.

I would suspect it is the open vent version and the F & e tank is empty or the cold fill is blocked where it joins the heating system

 

[corkybrandy]

Dave, you are right it is with the cylinder in the airing cupboard. Definitely tank in the attic, no idea what F & E is but should these be things they should routinely check from the symptoms ?

 

[gas4you]

The F&E tank is the small expansiond tank connected to the heating system in the loft, feed & expansion. This need to have water in to about a depth of 3-4 " approx. Sometimes ball valves stick and tank empties over time with evaporation. If tank is full could be blockage wher the 15mm pipe from the bottom of this joins the heating system in the airing cupboard.

Went to one today where customer called me in for a banging and smelly boiler, started off with hw tto hot then no hot water, Checked her f&e tank, it was full but tank lid had collapsed and bits had blocked feed pipe outlet. Cleared blockage, system filled boiler worked. Alas the banging and smell had been the boiler running dry once filled up water was pouring from her heat exchanger as it had now got a hairline crack in it caused by dry firing

New boiler going Thursday

 

[corkybrandy]

F&E tank located. Has 6-8" of water. Pipe at bottom has some build up on edges of inner pipe but was able to put my finger inside, no blackage felt. However, the noise I hear did indeed seem to eminate from the pipes leading from/to it but sound 10 times louder when in the sitting room.

 

[gas4you]

Could try putting magnet on copper feed pipe where it joins heating system, if it 'sticks' you will have a build up of sludge and possible blockage.

If you put a drain hose on a drain off and open it does f&e tank empty and consequently fill up as it is emptying. If so you do not have a blockage where i thought

 

[corkybrandy]

Thanks, beyond my capabilities and as a real DIY disaster veteran not giving BG chance not to find & fix. Appreciate your help.