Sludge

miken

My central heating system repeatedly fills up with sludge every few years.
British Gas who maintain the system last flushed it out but the cost is very high.
Anyone know a way of minimising this happening and any suggestions of Companies who can carry out this task for a more reasonable cost, based in Greater London.

The_Biff

I received a quote of over £1000 to de-sludge my old system, a few years ago, from BG. Haven't done anything else since except work out it would be cheaper to replace all ground floor radiators, which is where the sludge collects.

vansboy

The pressurised wash through, seemed expensive, probably worthwhile I suppose, but our plumber drained & refilled a few times & we seem OK now!!

VB

budgetflyer

Both "Fernox " and  "Sentinal" produce sludge cleaning products that cost around £15.
screwfix also do their own brand

http://www.screwfix.com/app/sfd/cat/home.jsp

Basically you drain the system,add the cleanser while refilling,leave to circulate between 1 day and 2 weeks depending how badly sludged the system is and then drain it all back out. Refill with fresh water, circulate and drain again to remove any eccess cleanser and sludge.

A power flushing machine can be bought for under £1000 so you can see the massive profit potential for companies using these.

Gaz_Hammer

Miken,
if you are getting sludge build up every couple of years then I would suggest that you have a potential major problem with your system.
Sludge build is normally due to the ingress of oxygen into the system either by a leak (where air can be drawn in) or through a badly piped up system (a combination of something like the open vent (expansion) pipe being too low and the pump speed too high for example).
However having said that if the system has never been treated with an inhibitor then that may be the answer due to water hardness (dependant on where you live!)

Power flushing or flushing is good for the system but is by no means a miracle cure as it will only repair on a temporary basis as you have found out. Without sounding too obvious, you need to find the cure!
Adding inhibitor is not just a case of sticking in a bottle of chemical, the water needs to be dosed to the correct level and any heating engineer should be able to carry out a water sample test using a water test kit to ensure correct dosage.

Hope you get it sorted
Gaz