Advice needed to power flush a home

[ey143]

Could I please get some advice on how best to approach the idea of finding the right company in NW London to powerflush a 4/5 bed semi home that has never been power flushed before and has radiators.

What are the things to watch out for and what is the correct way of doing it as I understand some companies take short cuts in the way they do it.

Thx.

 

[martygturner]

Is there a reason for the power flush ?...what is driving you to think you need one...cold spots on the rads, top of the rad hotter than the bottom, top of the house rads warmer than the bottom floor rads ? if none of these do you actually need a power flush ?

 

[ey143]

My 4 year old Viessman boiler has just gone faulty due to the heat exchanger being clogged by sludge and the engineer saying its full of dirt. Last week I had some builders doing up my bathroom and took off the radiator and emptied and refilled the system (and I had to remove all the trapped air). anyway home emergency gas boiler guy told me I should power flush it before fitting a new towel radiator.

I recall another safety engineer saying the same thing some 5 years ago when I had worcester bosch.

 

[Nige F]

Hertsplumbing and drainage ?

 

[HERTS P&D]

I would like to ask is there a magnetic filter fitted?

Andy

 

[ey143]

Yes, there is one on the central heating return pipe going into the boiler as per the pic (2nd pipe to the left with the gold thing) and has some anti scale thing on the cold inlet (second to the right).

Also what is an approx cost to power flush and how long does it take?

 

[HERTS P&D]

When was it clean out last? was it very dirty?

Andy

 

[ey143]

It is never been “power flushed” if that’s what you mean. My parents have owned the house since 1970 but of course the system has been drained lots of times since then.

Probably emptied completely and refilled some 3 or 4 times since 2017 when the new boiler went in at a different location in the extension including a complete empty and refill a few days ago.

I’d also say we’ve had 6 or 7 radiators either added to or replaced in the house in the last 10 years with now probably only 1 old radiator from the original 1970s. Most of the original copper pipes will be the same.

I’m not able to answer if it was very dirty. But if it helps I can confirm that when I bleed the radiator with the new water in, it’s still grey or blackish in colour when it comes out.

we should really have flushed it when we fit the new boiler in 2017 but it was never suggested by the installer at the time.

 

[HERTS P&D]

Sorry, I meant when was the filter cleaned out?

Andy

 

[oldbutnotdead]

Is this a pressurised or open vent system? - it sounds typical of f & e tank full of 30 years of dust has not been mucked out before system was drained.
EDIT Just seen your last post- question still stands (pressurised or ov). Modern boilers are much less tolerant of dust and bits in the water than older ones. If it is just dust then you don't need a powerflush (big machine, high pressure, abrupt pressure changes to dislodge corrosion), what you do need is to flush through all pipework and rads with mains pressure water (flush to drain), once you've done that, refill with water and system cleaner, let it circulate per instructions, drain and flush with fresh, then finally refill with clean water and inhibitor.

 

[ey143]

I recall the gold filter thing was cleaned out during the last service in Aug 2020. Was planning to do the next service this summer.

 

[ey143]

By open vent I take that to mean a small water tank in the loft? If so then no. It’s a sealed system and we top it up when it falls below 1 bar with a filling loop connected to the boiler.

The boiler has a 40 litre tank combined in the combi boiler system itself.

 

[Agile]

The boiler installer should have checked the condition of the water and ensured that it was totally clean.

Anyone doing an annual service should clean the filter and come to a conclusion about the condition of the water.

 

[ey143]

What would it cost me to get a power flush done? I have 14 radiators across three floors which including three towel radiators.

is there any risk to damage or burst to internal pipes when doing a power flush? What bar pressure do they operate at?

 

[JohnD]

As a first step, I'd suggesting getting a magnetic filter fitted, and giving it a chemical clean. if you are at all handy you can do the clean yourself for trivial cost. The chemical will loosen sludge so it can be captured.

this will at least catch remaining particles roaming around in the pipes and causing new blockages, and will remove at least some of the existing sludge and sediment.

It will need doing anyway, even if you have a powerflush later.

I think you will be amazed and delighted when you see how much sludge gets trapped in the filter, when you empty it out.

edit
Oh, I see you have a Spirovent. I have one, and it is not as good at trapping black sludge as a Magnaclean. Opinions will differ about this. Though it is a more solid piece of engineering. Not all of them have a magnet. I think yours hasn't.