POWER FLUSH NEEDED?

[jeff1954]

My combi boiler (Alpha) has been cutting out last few days due to low pressure - let more water in and it has been ok.
But I noticed the overflow pipe on the outside wall has been leaking some brown sludgy type seepage
Called the company with whom I have a maintenance contract, and after examination they decided the Repression Expansion Vessell requires new PRV and they also recommend a Power Flush - cost £500 plus vat - there are seven radiators in the house.
Whilst I realise it needs to be examined personally - does this sound like a reasonable quote from what I have stated.
Haven't been having any apparent trouble with any of the radiators or water heating
Any comments would be appreciated.
Cheers

 

[JohnD]

lots of people recommend a powerflush

A powerflush costs a lot of money

there may be a connection between these two facts

I am just a householder and might be wrong.

Quite likely the corrosion has been caused by repeatedly adding fresh water to the system, which has introduced dissolved air and diluted the corrosion inhibiting chemical that (ought to be) present resulting in rust inside your steel radiators and black corrosion.

Any circulating corrosion sediment is undesirable as it can cause wear and blockages.

If you have not got a blockage yet, there is a lot to be said for fitting (or having fitted) a Magnaclean device which will trap a lot of black sediment that might be in your system. You can add a chemical to loosen it, which can be left in the system indefinitely.

After the fault has been fixed you must have a corrosion inhibitor added, this will prevent further corrosion.

 

[hi-spec plumbing heating]

is that all them jobs 500 or just powerflush if thats just powerflush tell them to poke it.

as bad as bg

we do seven rads standard house £350. +£25 each extra rad.

 

[Softus]

You can add a chemical to loosen it, which can be left in the system indefinitely.

I'm afraid you can't, because doing do won't protect the system from further corrosion.

 

[ChrisR]

No evidense there that you need a powerflush. Repressurise the expansion vessel which you can do yourself (see faq). If the prv keeps leaking you need a new one of those. Add some corrosion inhibitor to stop it getting worse and see how it goes.

 

[JohnD]

I'm afraid you can't, because doing do won't protect the system from further corrosion.

yes you can... I did also say "After the fault has been fixed you must have a corrosion inhibitor added, this will prevent further corrosion."

Sentinel now say X400 does not have to be drained out. It seems to me this is particularly handy if you have a magnetic device (if not, the loosened sediment will not come out until you drain it and I suppose it would eventually settle)

 

[bengasman]

For some reason installers fitting your type boiler often forget to flush the system properly. Chemical cleaners soften the sludge but will not break down or remove limescale or rust. The only way I know of getting rid of those completely is powerflushing it with fx2. Not suitable for all boilers though as it is a bit aggressive. If your boiler is leaking to the outside, chances are you need to replace your prv and pump your expansion vessel back up to about 1 bar. To do this you need to reduce the pressure in the system first to below 0.5, otherwise your reading may not be accurate. It will also show if your expansion vessel is just low, or leaking.