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Power flush of the central heating system

(26 Posts)
HelterSkelter1 Fri 05-Jun-26 08:27:42

Anyone had a power flush? Was it successful? Any down sides? Extra leaks?
Was it expensive and did it take a whole day or a few hours?

Just had a new pump fitted and a power flush was recommended. Our central heating system was installed 40 or so years ago. The boiler was replaced 7 years ago and is regulalarly serviced.

We have used the same company for the last 20 years.

TillyTrotter Fri 05-Jun-26 08:43:30

Yes we have.
No leaks, just a better flow of water through the radiators. A product is put in that sluices the sludge that collects in the pipe work.
We have a central heating overhaul every 12 months.
It took about 4 hours (4 bed house) and it isn’t cheap but we have hard water here and it is necessary every few years.
Cost as I remember last time a few hundred pounds.

HelterSkelter1 Fri 05-Jun-26 08:47:51

Thank you Tilly. Thats very helpful

Greyduster Fri 05-Jun-26 08:48:45

I had a complete system change in 2022, and the system was power flushed then as part of the installation. I was very nervous about it as we have microbore piping which doesn’t lend itself readily to powerflushing. If your system was installed 40 years ago I doubt your pipes will be microbore so flushing shouldn’t cause any problems but the plumber will advise you. Your system will work better for it. It’s relatively straightforward and shouldn’t take a whole day.

Jaxjacky Fri 05-Jun-26 08:55:54

Yes, we’ve had it done, as other have said it helps the water flow, no problems afterwards.

J52 Fri 05-Jun-26 09:05:30

Yes we’ve had it done in past houses, with no problems. It does help as there can be a build up of sediment? over a period of years
Our current system was installed new as the old one was inefficient so a power flush is not needed yet.

Charleygirl5 Fri 05-Jun-26 09:13:43

I had it done when I had a combi boiler installed a couple of years ago, Microbore and very hard water here also. I can't remember the price, but there were no leaks afterwards. I trust the gas engineer who has been looking after my system for years, and he wouldn't recommend unless he thought it was necessary.

The weather was warm because he hasn't learned to close the front door!

HelterSkelter1 Fri 05-Jun-26 09:16:59

Thank you everyone. Has put my mind at rest.

shysal Fri 05-Jun-26 09:18:51

British Gas suggested this a couple of years ago. I think it is something they were pushing at the time, as I heard of other customers being told the same. It was not mentioned at the next service.
I had a drop in boiler pressure recently and BG brought in Dyno Plumbing to check for under floor leaks. Fortunately it was a radiator leak above ground, but on chatting to the chap he advised me not to use BG for the flush as they are expensive and don't always do a good job. I took it with a pinch of salt but will bear it in mind.

HelterSkelter1 Fri 05-Jun-26 13:42:45

I had a BG boiler service which was not good at all. I went back to our boiler people for the nest one and kicked myself that I chose BG instead of them that year.
I only went with BG that time because they were offering a cheap deal. Pay peanuts ..get monkeys. So true

MT62 Fri 05-Jun-26 13:43:32

If Rads are so old would new radiators be an option?

HelterSkelter1 Fri 05-Jun-26 19:02:45

Not all the rads are old.. ten in total and 2 small bathroom ensuite ones.
Four are old the rest newish. And when we had the new boiler in 2019 they added chemical to the system, but not a power flush. The old rads are still working fairly well.
We have hard water. I think a power flush is the 1st step to help the general flow of water. I dread having a blockage mid winter.

This time the plumber blasted compressed air down one of the pipes in the loft to see if he could shift a blockage so the the new pump he put in would start wotking. Which it did.

ClicketyClick Sat 06-Jun-26 16:20:06

The poster who reported Allira needs flushing out.

sharon103 Sat 06-Jun-26 16:28:50

I had a power flush when I had a new combi boiler fitted. All in with the price.
No leaks. All good.

Greyduster Sat 06-Jun-26 20:40:50

When you have a new boiler fitted, it’s often (not always) a condition of the manufacturers guarantee that the system has been flushed.

HelterSkelter1 Sat 06-Jun-26 22:01:10

I must check the invoice for the new boiler we had fitted in 2019 and see if they did a power flush then or just chemicals added to the tank.

PinkSweetPea Sun 07-Jun-26 13:40:50

I had a new boiler 2 years ago and the engineer did a power flush it was included in the price of the boiler. One of the radiators that never got very hot in the past after the power flush now gets to a decent heat so happy with that.

Sadie5803 Sun 07-Jun-26 13:43:10

Be careful, our system is 36 yrs old, was offered one, but after research was advised to leave well alone, as pipe joints could leak under pressure and they won't take responsibility, plus seeing the joints are under floorboards/carpets you wouldn't know until the leak came through the ceiling...TOO LATE..., I had a cleaning additive put into my system, alot better and cheaper...BUT ITS PERSONAL CHOICE

cc Sun 07-Jun-26 13:49:54

I would never recommend BG for anything. My mother had a contract with them which was supposed to include cheaper boiler replacement, but in fact cost significantly more than our own plumber for an identical boiler.

Casdon Sun 07-Jun-26 13:51:41

Yes, Ive got a closed heating system, and had a power flush before my new boiler was fitted. It was fine except one error on the part of the company, which I was really cross about. The pipe at the end of the flush was sited in the shower room, as that is the last radiator on the system. The flushing involves corrosive liquid, and they didn’t put down a protective sheet, some spilled, and it took off the shiny surface layer of the marble floor of the shower room, there was a big ring of matt surface left where the bucket was. Make sure they put the draining bucket on some polythene.

Ilovecheese Sun 07-Jun-26 13:53:10

I think if you live in a soft water area, a power flush is a waste of money.

win Sun 07-Jun-26 19:22:08

I have had a couple and they make a big difference. I have never had any leaks but it is always a job to get rid of airlocks in our system because we have extended our bungalow so many times, our plumbing is a bit of a botched job. It took a whole day both times. I will still have it done next year, I usually do it every 3 years after we had a new boiler as I want to keep if 'well'

Maggiemaybe Sun 07-Jun-26 19:56:34

Ilovecheese

I think if you live in a soft water area, a power flush is a waste of money.

I think you’re probably right there. Our water’s very soft and we were persuaded to pay for a power flush years ago. It didn’t cause any problems, but we didn’t have any before the flush either. smile

Azalea99 Sun 07-Jun-26 22:31:36

I’m 100% with @Sadie5803
Where a radiator has a cold area I really think it’s safer to have that particular one removed and flushed clean then reattached. They can just use some gadget which freezes the pipes either side (or maybe just one side) of the radiator before removing it, which means there’s no need to drain the system. Insurance won’t cover you for the mess/damage caused by leaks and the plumber will be obliged to warn you in advance of the possibility of leaks….. which could well be beneath the floorboards. My system is more than 36 years old, pretty good overall all serviced every 18 months. I won’t take that chance.

Menopauselbitch Mon 08-Jun-26 08:45:44

Azalea99

I’m 100% with @Sadie5803
Where a radiator has a cold area I really think it’s safer to have that particular one removed and flushed clean then reattached. They can just use some gadget which freezes the pipes either side (or maybe just one side) of the radiator before removing it, which means there’s no need to drain the system. Insurance won’t cover you for the mess/damage caused by leaks and the plumber will be obliged to warn you in advance of the possibility of leaks….. which could well be beneath the floorboards. My system is more than 36 years old, pretty good overall all serviced every 18 months. I won’t take that chance.

I thought if a radiator has a cold top part it just needs bleeding.