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Powerflush central heating

Does what it says on the tin
swill453
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Powerflush central heating

#152011

Postby swill453 » July 12th, 2018, 5:00 pm

We're getting quotes for a new boiler and general upgrade of our central heating. One variation that one of the suppliers has quoted for is to replace the boiler and all radiators, and to powerflush the system.

Is there any point in a powerflush with having so much new stuff? Presumably this is just for the pipework, how much benefit would that be, over simply draining it? It's not been separately itemised so I don't at the moment know what I'd save by not having it.

Scott.

Dod101
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Re: Powerflush central heating

#152014

Postby Dod101 » July 12th, 2018, 5:12 pm

Well powerflushing removes the gunge in the system which simply draining the system is unlikely to do. I had mine done last Autumn, certainly for the first time in 12 years that I have been here and probably longer and it has helped in terms of the water flow and thus heat distribution. I am told that it also puts less strain on the heating pump and probably boiler and so should reduce the amount of fuel used. It is a time consuming business though and that I think is the main cost. It is for the pipework and more importantly the radiators.

I would get it done at the same time as your new boiler.

Dod

swill453
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Re: Powerflush central heating

#152015

Postby swill453 » July 12th, 2018, 5:17 pm

Dod101 wrote: It is for the pipework and more importantly the radiators.

So that gets to the nub of my point - if I get all new radiators, is it worth getting the powerflush just for the pipework?

Scott.

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Re: Powerflush central heating

#152017

Postby Slarti » July 12th, 2018, 5:27 pm

Wouldn't it depend on how much pipework there is?

If you have long runs, due to the shape of the house, then it may well be worth it.

We had our system done with the new boiler, but have not had any radiators replaced. It did take a while, but they just connected it all up and left it running for an hour or so while they got on with other stuff.

As it was done in May and I haven't had the heating on since then, I have no idea if it will have made any difference.


Slarti

tea42
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Re: Powerflush central heating

#152021

Postby tea42 » July 12th, 2018, 5:41 pm

I have done it myself. With existing radiators you should flush the system one radiator at a time and bang the radiator with a rubber hammer to loosen any sediment. It took me most of a day. It did speed up the response of the system, it heated up faster. That was 10 years ago. I am having it done again this summer because I believe it saves money and heads off problems.

Dod101
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Re: Powerflush central heating

#152022

Postby Dod101 » July 12th, 2018, 5:44 pm

swill453 wrote:
Dod101 wrote: It is for the pipework and more importantly the radiators.

So that gets to the nub of my point - if I get all new radiators, is it worth getting the powerflush just for the pipework?

Scott.


Certainly to a layman it hardly seems worth it. On the other had you can hardly have the system powerflushed without the radiators so presumably it will be done after the new radiators are installed and on that basis I think I would have it done. Shame to spoil the ship and all that. There is also some sort of additive which apparently helps clear it through or seals the system.........or something.

Do you know the installer well enough to trust his answer to the question?

Dod

Itsallaguess
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Re: Powerflush central heating

#152035

Postby Itsallaguess » July 12th, 2018, 7:05 pm

swill453 wrote:
We're getting quotes for a new boiler and general upgrade of our central heating. One variation that one of the suppliers has quoted for is to replace the boiler and all radiators, and to powerflush the system.

Is there any point in a powerflush with having so much new stuff? Presumably this is just for the pipework, how much benefit would that be, over simply draining it? It's not been separately itemised so I don't at the moment know what I'd save by not having it.


Do your quotes include the installation of a system-filter, similar to the Fernox TF1?

https://www.screwfix.com/p/fernox-tf1-t ... 22mm/84311

I only ask because if they don't, and you're perhaps looking for a cost-compromise, and where it seems like you're replacing everything except the installed pipework anyway, where there is less likelihood of any major gunge build-up, then I'd perhaps think about foregoing the power-flush and insisting on the installation of a Fernox filter instead, and ask them to dose the system with inhibitor when they've finished.

That way, you'll end up with a protected system, and more importantly a good method to self-dose and filter any existing or new gunge that develops anyway. These filters are usually installed just prior to the boiler, so should capture any low-level existing issues, and anything that builds up in the future.

Just something to think about, as you didn't specify the filtering side of things, and I wanted to check that you'd considered it.

I wouldn't install a new boiler without a similar system filter....

Cheers,

Itsallaguess

stewamax
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Re: Powerflush central heating

#152040

Postby stewamax » July 12th, 2018, 7:59 pm

A powerflush that does not involve working around the system switching on just one radiator at a time and using a vibrator to loosen the sludge is just a more powerful version of turning up your pump to full, opening the drain cock on the cold boiler (don't let the pump run dry...), and opening the wheel valves one by one.
There are different interpretations of power flushing, but a 'proper' powerflush can take a day or more to do properly.

I would just install a Magnaclean or Fernox filter coupled with an adequate doseage of inhibitor (e.g. Fernox MB1).

Dod101
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Re: Powerflush central heating

#152067

Postby Dod101 » July 12th, 2018, 10:12 pm

I guess I had the full stewamax because my powerflush took the best part of a day and certainly the guy worked around the system radiator by radiator. Still if the OP is installing new radiators that is not going to be necessary I would have though so maybe simply flushing through the pipes and using the inhibitor would be adequate. I would always ask the installer carefully for his recommendation but then I know I can trust my man to tell me the truth which is why I asked the question.

Dod

dspp
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Re: Powerflush central heating

#152114

Postby dspp » July 13th, 2018, 9:30 am

swill453 wrote:
Dod101 wrote: It is for the pipework and more importantly the radiators.

So that gets to the nub of my point - if I get all new radiators, is it worth getting the powerflush just for the pipework?

Scott.


Just from my experience:

1. It may be a requirement of the boiler mf that a powerflush is carried out prior to install in order for warranty, or extended warranty, to be valid.
2. There will be gunge in the old pipes, not just in the old rads.
3. Any self-respecting plumber should dose with inhibitor. If not, don't use that plumber.
4. Those filters are a good idea.
5. At a friend's property some plumbing works were done to my spec. In the spec I included the requirement to "flush through, inhibit, and set to work". The plumber who did that is claiming that the instruction to "flush through" is not to "power flush through" and so only did the former. I could not imagine that you would do anything other than a power flush (as I am coming from experience of large industrial piping systems), and so was appalled at his response. However, crucially, the work was not carried out on my property and I did not find out until he had cleared off the site declaring everything working. Needless to say everything is not working and I strongly suspect at least one radiator is choked by dislodged deposits. The toss is of course being argued with the plumber and a suitable retention witheld.

All in all, my personal opinion, is go with the powerflush. I will be very clear in any specs I write in the future on this point.

regards, dspp

stewamax
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Re: Powerflush central heating

#152151

Postby stewamax » July 13th, 2018, 11:27 am

Intriguingly, Viessmann do not recommend the use of a corrosion inhibitor at all, and only the use of a hardness inhibitor "where it is known that boiler feed water contains a high mineral content and hardness [above 300ppm]" or a special-purpose antifreeze "in areas where freezing might occur"
For sealed systems, not adding a corrosion inhibitor may make some sense - there is only so much oxygen in the circulating water to cause the iron in the radiators to corrode - but for their open-vented systems such as the 100-W Open Vent the header tank oxygenates the water even when there is minimal need for fresh water and/or minimal pump-over.
Products such as the ubiquitous Fernox MB1 claim to be both a corrosion inhibitor and a hardness inhibitor, and boiler manufacturers such as W-B recommend that you do not use water from a water softener to fill the CH system but use a corrosion and hardness inhibitor instead.

I have no idea whether the W-B and Viessmann recommendations differ just because the former use aluminium heat exchangers and the latter stainless steel ones.

swill453
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Re: Powerflush central heating

#152233

Postby swill453 » July 13th, 2018, 5:49 pm

FWIW all the quotes I've had have specified a Magnaclean filter or similar.

Interestingly most aren't recommending Worcester Bosch nor Vaillant boilers these days. Two have independently recommended ATAG as a "higher end" option or Baxi as a cheaper alternative.

Scott.

bruncher
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Re: Powerflush central heating

#152316

Postby bruncher » July 14th, 2018, 12:49 pm

swill453 wrote:FWIW all the quotes I've had have specified a Magnaclean filter or similar.

Interestingly most aren't recommending Worcester Bosch nor Vaillant boilers these days. Two have independently recommended ATAG as a "higher end" option or Baxi as a cheaper alternative.

Scott.


We're probably looking to buy a new system soon. Not sure whether to wait until it (Potterton Profile) fails, or do it sooner. ATAG is a Netherlands company as is BDR Thermea which now owns Baxi. BDR Themea also offers Micro CHP and I wondered if any Lemons had considered this or knows anyone who has a CHP unit, and can say how it's working out.


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