Flush my central heating?

I would say if a gas reg plumber can do it anyone can, it is not rocket science,

fred
January 2013

sludge in central heating systems is caused by electrochemical interaction between copper and iron(steel). If the installation is properly done, a corrosion inhibitor will have been added to stop the corrosion and hence the sludge. With older header tank based systsem its was easy to add and to topup. With closed loop boilers (Combi and Condensing it is impossible almost to add the corrosion inhibitor. In my system 30 years ago and no problems with sludge.
If you have sludge the best way of getting rid of it is to remove and flush each radiator with mains water ensuring the air bleed valve is open to prevent airlocks. Dont this ona lawn as the sludge will kill the grass! with all the radiator valves sh*t, you can then flush the pump and backbone pipework, again using hoses and mains pressure. Run until all the water is clear. Reassemble the entire system. Using one upstairs sized radiator connection open one of the valves and using a funnel and flexible hose pipe, pour the contents of a 4 litre container of corrosion inhibitor into the system. Fit the radiators, and then fit the system with a filling loop, allowing air to be expelled from the downstairs radiators and then the upstairs

stewart bray
May 2012

pressure is set for to bar but when system is running pressure goes to 3.5 bar what is wrong

jim bradshaw
February 2012

Firstly I don’t mind DIYers, if people want to DIY that’s fine and it’s something new to learn. I am a power flushing expert and a member of the power flush association. My clients simply don’t want to, or failed trying to power flush.

Fact:
Using a de-sludger will get the sludge all loose and it will ALL drop of the internal walls, of the system and just lay there at the lowest points. Sludge is metal and heavier than water and will need high flow rates and velocities to move around, which your pump cannot do because that would make it in-efficient and costly to run – so it can’t by design. It is also not supposed to, as your system is not supposed to have sludge in it.

If your problem is really bad: (tons of sludge on internal walls over many years)
Draining it down will not do anything, the sludge will be lying on the bottom of radiators, pipes and boiler and is more than likely to cause you trouble as the pump moves some of it to even lower points with less flow – causing even less flow. But that does not mean you can’t try it, if it fails get a professional; at least it is all loose and ready to be removed.

Is power flush a DIY job:
1) Only if you know how to remove and fit back a radiator and fully understand your system. You can break a boiler if you use a large power flush machine (like the ones you rent) and close the wrong valve at the wrong time on certain boilers.
Flooding is also a real risk if you get it wrong, but normally it’s something you notice quickly and can turn the machine off.
2) and have a system that is all working fine. It's 10 times more complicated to flush a system that has problems, and you need experience to know how to treat each different problem.

Power Flush Guy
November 2011

bg have just been to my property and recomended a power flush boiler & pads £703 only 3 months ago it was serviced and no mention of this then although a diaphram was replaced any input anyone seems a lot of dosh

brian
April 2011

Power flushing involves using a power flush machine, no matter how many online manuals you read. You cannot replace the experience of a professional, when in doubt use a member of the PowerFlush Association.

TopPlumb
April 2011

Beware British Gas so-called engineers! When I had boiler problems, 3 in a row said a £350 power flush was needed, but I eventually contacted a proper independent engineer who immediately diagnosed a faulty flame detector electrode, which cost under a fiver, and took less than thirty minutes to fix. I binned BG after that, and the independent guy now has the maintenance contract for my 3 properties, and has picked up business from 4 of my friends who were also displeased with their experience of BG.

DavidCH Leeds
March 2011

Yes but the results might not be as good as using a member of the power flush association. Look online for DIY power flushing videos first - then decide if it's worth it and that you will be able to do it yourself. You can hire the machines, also look online.

Robertplumber
March 2011

British Gas seem to be very keen to sell this Power Flush to customers. Last autumn some radiators weren't heating up (just after annual BG service!). Engineer replaced pump but gave us a quote for power flush, which he said was needed as water was black and sludgy-looking. However, central heating has been running fine all winter. Had engineer back this week as header tank was leaking from overflowpipe. Engineer turned down pressure in the pump slightly but said power flush was needed as there was probably a blockage in the system. Power flushing seems to be the answer to all problems! Furthermore the lifetime guarantee only applies if you don't have any building work done on your house.

FranW
March 2011

My rads are hot upstairs, but cold downstairs. 1 engineer said it was the pump so went on an insurance scheme. Called engineer out who has now said it's the diverter valve. Different engineer has been out to fit the new valve and said it's not the diverter valve, he's 99% sure there is sludge in the lower pipes. I'm now totally lost and have no faith in what anyone has told me. Any thoughts on what it could be or what I could try myself?

Mooro
February 2011

POWER FUSHING IS NOT A PROVEN WAY JUST A WASTE OF MONEY,LET THE BOILER PUMP FLUSH THE SYSTEM,IT WORKS ON THE SAME PRESSURE AS A POWER FLUSHER a good quality flushing liquid,put it in the system,best to put it in the radiator nearest the boiler.switch on the boiler for six hours,then close of all the radiators except two run for 4 hour with just the two radiators on,then close the the radiators of and open another two radiator and run for a further four hours and do this until all the rads are flushed and run the system for a month,drain and refil the system using a realy good inhibitor

Dave
November 2010

Mindfield!!!! never a simple answer to a simple question!!!!!!!!!!! must be all plumbers replying!!!

Tired of rip off plumbers
November 2010

My central heating is working well, although the bottom quarter of the rads are cooler than the top. We recently had a new pump installed under our bg service plan, and BG told us the water was black in the sytem and recommended a power flush. This was 3 months ago and although you can sometimes hear the water running randomly into the rads the general heating and hot water is excellent. We are wondering whether to spend 700 on the flushing as recommended or wait till the heating breaks down.

J M
September 2010

putting chemical in the system then draining down ISN'T A FLUSH!! Power flushing is good but on complex systems you need experience, you need to make sure you have a good flow or it will not work. Single pipe systems require rads taking off wall & flushing with MCW (if you connect a power flush pump the flow will just go around the loop)

A proper plumber
September 2010

Fed up of plumber's charging me for a supposed flush and then it not doing much so called B,gas. their flush comes with a lifetime insurance so if required in 7-12 yrs time if you need a proper 7-8hrs powerflush again it's free! Now my rads are hottest ever !

Dave Carter
August 2010

Yes

michael
February 2010

No i have just had mine done £300, the equipment is expensive and the conections for the flush are complicated. Various chemicals have to go into the system while the flush is taking place and then have to be tested to make sure they are out of the system. this is not a diy job!!

GARY HART
February 2010

easily done. but not so easy to do it properly. Special chemicals needed and could take a day for them to work. Recomend gettin a plumber. they have the pumps and equipment needed.

Mark
January 2010

do you leave the pump on when flushing so that the dirty water can get into the system from the boiler?

Alfie
January 2010

Question for sexy richard the plumber:

Richard - When you say drain off enough water to from the central heating system, what do you mean by this?

Do you simply bleed a radiator into your hose pipe?

Richie9
December 2009

ITS SIMPLE-EVEN IF YOURE A NOVICE.
FIRST OF ALL,IF YOUR RADS ARE HOT UPSTAIRS AND COLD DOWNSTAIRS,THERES A GOOD CHANCE YOUR PUMP NEEDS REPLACING.
BUT IF YOU HAVE AIR IN THE SYSTEM YOU CAN EASILY REMOVE IT BY CONNECTING A HOSE-PIPE TO A DOWNSTAIRS RAD AND FLUSHING IT OUT.TO DO THIS,FIRST TURN OFF THE RAD,THEN IF YOU LOOK AT THE BOTTOM END OF THE RAD YOU,LL FIND A LITTLE NOZZLE WITH A SQUARE PIN INSIDE-OPEN(TURN ANTI-CLOCKWISE)THE VALVE,A LITTLE WATER MIGHT COME OUT SO HAVE A TOWEL UNDERNEATH.THEN PLACE THE HOSE OVER THE NOZZLE AND RUN THE HOSE OUTSIDE,USE A JUBILEE CLIP TO SECURE IT TO THE VALVE IF POSSIBLE-THEN TURN THE RAD BACK ON.20 MINUTES SHOULD DO IT-DONT FORGET TO TURN THE RAD BACK OFF BEFORE REMOVING THE HOSE

BOBS YOUR UNCLE
November 2009

my exspanshion tank is driping i hade b/gas out think its the pipe blocked with hade water how do i flush it out

howard
September 2009

how to flush heating system

gary
July 2009

wot would happen if you don't remove the system cleaner

john
February 2009

I Have a Worcester Heat Slave combi 18 yrs old and am looking to replace with condensing combi.
Would like to flush my system and replace TRV's and Lockshield valve my self to save some money.
Is it his reasonable? I am good at DIY and have most tools.
I realise that this system is unvented, does this make it harder to do? any explanation welcome. Thanks Martin

Martin King
August 2008

i would say the best thing to do is to drain all the water out using the drain off. then turn off all the rads and remove them all then refill your system with some c h system cleaner then put it on full wack take all ur rads out side and connect up to ur out side tap via a hose and blast water through them till there clean then re hang and connect up but not opened the rad valves then connect up ur hose to ur drain off and allow water to slowly come out in to a drain then after 20 min turn off the boiler turn off drain off and alowe to cool for 10 mins then drain all water out of system by shuting off the feed to the f and e then re fill system and pump for five mins then drain down shut drain offs and then add ur inhibitor to the f and e and allow refillling then go round open all rad valves and blead all the rads after doing that restart boiler and it should work ok for year after a week or 2 go round and vent the last little bit off air in the rads

sexy richard the plumber
September 2007

Come on, give the British Gas Engineer his commission... Ask them for a water sample first - They use Salamander which is an external company and is worth the wait as it will explain whether or not a manual flush could restore the problem.

Ok... As for whether or not you can do it yourself:

Powerflush = Not unless you are very good at DIY or just stupidly brave.
Manual flush = Only if you are confident at draining and filling your c/heating system.




I'm not going to explain powerflushing as I think that novices should stay well clear as doing it properly takes good engineering judgement and skill to not splatter the walls in the sludge you will be removing.


Manual flush; pop down your local plumb center and pick up a bottle of "desludger" or "system cleaner" and a bottle of "inhibitor" check with the merchant the quantity required for your system size (Make sure you know how many rads you have)

Rush home with your new items and put the system cleaner in the header tank in the loft; get your hose out the shed and drain off enough water from the c/heating to ensure that the entire contents of the header tank are pulled into the circuit.

Check the instructions on the bottle; most are 4 weeks maximum "in-system" time... Run your c/heating as hot as you can for this period, then, simply drain the entire system... Fill it with fresh water and let it run for a few hours... Then drain that again... Then add the inhibitor; and fill... Job done.


Alternatively; get 3 quotes to go with your b'gas quote from REPUTABLE plumbers in your local area - Do not search the yellow pages unless you know what you are looking for... Make sure the plumber carries adequate insurance for the job and ensure that they sheet up before commencing work.

GasAid.co.uk
January 2007