Flushing a system before new boiler , help me understand

[men8ifr]

It seems a bit of a mystery what consists of a good or bad job for flushing a CH system before installing a boiler.

I believe british Gas have a machine to flush the system but they charge 1-2K more than my local inataller to do the job so it's a premium I'm not going to pay.

Also I cannot replace the radiators I have so need to keep them and they are quite old 10-20 years maybe.

So what should be done to flush the system well?

What would be considered not doing the job well?

Can a filter be fitted so any bits are captured in that?

Is the problem bits of rust/debris blocking the entrance to the heat exchanger?

Thanks for your replies.

 

[lightning]

http://www.kamco.co.uk/powerflushing.htm

 

[men8ifr]

What about fitting a filter before the boiler - is that ever done, or necessary? Maybe boilers have these integrated into them?

 

[cumbriahandyman]

 

[DP]

Corrosion in heating systems takes two forms. One is sediment that is suspended in system water to paint all surfaces it contacts (HW HE being a prime example leading to hot/ cold/ hot/ cold etc hot water). Over time the layer gets thicker. Second form is sludge that sits in the valleys at the base of the radiators and bottom of the main heat exchanegrs, and also leads to premature pump failure and motorised valves getting destroyed.

While I am not saying the way i do it is the only way the task should be carried out, but am saying if I carry out system cleansing, I am then responsible for system to operate without failure due to system corrosion.

Initially I like to remove heavy sediment from the radiators by either power flushing or fast flow of water from the mains along with shocking the radiator with rubber mallet. One radiator at a time gets this treatment. Water during this exercise only flows through the base rib not mixing/ diluting what is above the said rib. Multiple shocks later water outflow will be quite clear. It will be appreciated, if shocking the radiator realeases no sediment, normal operation will not disturb what remins in the valley at the base of the radiator.

To clear what remains above the base rib, system is now treated chemically. Chemicals will now clear out the whole system. Follow instruction and finally flush as per the maker's instructions.

Inhibit system. If you must, fit Spirorteck (though not necessary as system will be nice and clean).

Above adds about two days to boiler change. To drain and fill system does not remove system debris.

 

[expertgasman]

Also I cannot replace the radiators I have so need to keep them and they are quite old 10-20 years maybe.
I can't believe it can't be done, so presumably you mean you are not able to pay for the work?

So what should be done to flush the system well?
A proper powerflush

Can a filter be fitted so any bits are captured in that?
Yes

Is the problem bits of rust/debris blocking the entrance to the heat exchanger?
Amongst others

Is this a wind up?
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Author Message
DP Posted: Mon Jul 25, 2011 7:22 am Post Subject:

Inhibit system. If you must, fit Spirorteck (though not necessary as system will be nice and clean).

Above adds about two days to boiler change. To drain and fill system does not remove system debris.

TWO DAYS!!?

 

[Agile]

Also I cannot replace the radiators I have so need to keep them and they are quite old 10-20 years maybe.

Of course what he really means is that he does not want to PAY for new rads.

Equally he does not want to pay for the existing rads to be power flushed and thinks that simply draining and refiulling has the same effect.

What he is actually doing is to say that he thinks that heating engineers are rip off cowboys who want to charge for ineffective and unnecessary work.

He does not seem to realise that we are totally unbiased and giving our advice free and none of us are going to be involved in his work.

Its such a pity that Rogue Traders has given the public such a bad image of our profession. Thats only an entertainment program!

Nor do I think that video does anything to enhance the image of our trade either!

 

[expertgasman]

Also I cannot replace the radiators I have so need to keep them and they are quite old 10-20 years maybe.

Of course what he really means is that he does not want to PAY for new rads.

Equally he does not want to pay for the existing rads to be power flushed and thinks that simply draining and refiulling has the same effect.

What he is actually doing is to say that he thinks that heating engineers are rip off cowboys who want to charge for ineffective and unnecessary work.

He does not seem to realise that we are totally unbiased and giving our advice free and none of us are going to be involved in his work.

Its such a pity that Rogue Traders has given the public such a bad image of our profession. Thats only an entertainment program!

Nor do I think that video does anything to enhance the image of our trade either!

WOW, it doesn't happen too often, but I agree with Tony on this.

 

[DP]

Yes, takes me around two days.

Day one. Clear out one radiator at a time. Average 8 radiators in a house.
Set up to connect PF machine or connect mains water to an appropriate point. Connect drainoff pipe to system. Turn all rads off except one and do what I describe in my text above.

Day 2. Drain system as per maker's. Fernox DS40 instructions say fill, vent, circulate, vent etc and then drain at least 6 times or until water is clean. Expertgasman care to speculate time it takes to do that? Am not here to beat my drum, but what I aim for is a completed task that will not require subsequent visits due to cutting corners. Do I do many jobs like this? No I do not, but ones I do are for clients who wait for me and I do not compete or undercut others. Finally aim is to carry out a task with the motto 'get it right first time' and not 'that will do- who is to know'

 

[Agile]

I have never had any problem with dirt in a system which I have cleaned!

But it does take time as DP explains and the customer does not get this for £30.

I also take the view "do it properly and only do it once"!

I go to so many systems that have been "cleaned" only to find its full of dirt.

 

[gasservice85]

normally 2 of us and we can get it done in a day (8-6)

its suprising having 2 people makes much difference on powerflushing but it does

 

[Agile]

In a two story I find it quite a lot of exercise and quite tiring on my own.

Not a problem on single floor properties.

Tony

 

[DP]

Power flush can be done in a day, BUT what about the water above the base rib on the radiator that power flusher fails to clear out?

 

[gasservice85]

I use jetflo powerflusher and magnacleanse connected up aswell with agitator and x800

 

[Whitespirit66]

Also I cannot replace the radiators I have so need to keep them and they are quite old 10-20 years maybe.

Your rads aren't old, believe me. The ones in my house were installed when my house was built in 1961. My system is clean, and I never have any problems with internal sludge/corrosion. I have worked on plenty of systems with much older rads.

Unless you have problems with blocked rads, heat exs, or the water you drain out contains sludge, just do a chemical flush with Fernox, etc, and fit a filter eg Fernox TF1. It's important that after refilling your system, you make sure that corrosion inhibitor is added to the correct concentration. Make sure you maintain this concentration in the future.