Is there a standard job specification for carrying out a Powerflush?

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Hello guys,
I'm choosing a contractor to carry out a Powerflush as CH flow is poor on the ground floor of my 3 floor townhouse The boiler (12 months old) is on first floor, 3 way valve and pump (both 18 months old) are in airing cupboard on second floor.
We had a Powerflush carried out about 4 years ago for the same reason, but the guys doing the job never removed any radiators and there was no evidence that they'd treated the water with any inhibitor when they'd finished. I'm no expert, and I only found out later that this is normally considered part of the job.
Are there any standard specifications for what work should be done for a Powerflush, so that I can I ask the company to confirm they will be working to this standard when they quote for the job?
 
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You wouldn't normally remove radiators as part of a powerflush, just flush them individually by turning all except one off and moving around the house doing one at a time (but with the machine staying in the same location, normally attached to the pump) Inhibitor should definitely be added at the end of the job, and the job would normally take an entire day
 
Thanks muggles - if they're not removing the radiators, what else are they doing for the job to take all day?
 
Turning valves on and off - you leave the radiators connected, turn every one except the one you want to flush off, when that's flushed properly, turn the next one on and go back to turn the first one off. Repeat until all rads are done. Typically 10-15 mins per rad
 
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If you want a good description of how its supposed to be done, look at the Kamco web site (http://www.kamco.co.uk/GuidanceNotes/PDF/CF30Instructions.pdf).

The job takes all day because it often takes an hour to get set up, at least an hour to flush the whole system with all radiators, then as muggles said 10 to 15 minutes per radiator - and it can often take more if they need to be "agitated", then flushing to drain, re-flushing the radiators and system, testing the water and packing away. This does not include time mopping up when you forget to shut off the cold water fill valve!
 
Thanks guys, this is very helpful.
Also, I didn't know there was a Benchmark standard for boiler installation - I'm wondering whether the guys who put in a new Vaillant boiler 12 months ago actually flushed the system at the time or whether they simply shoved it in and ran away (The property was rented out at the time and we were not around to see the work done) It's a shame it seems that noone can be trusted to do a job properly these days - which is why I was asking about the Powerflush job specifications.
 
4 years between the need for power flushing is indicative of an underlying fault with the system.
You must be getting a lot of air in; probably from the F&E tank for the central heating. It would be worth considering having the central heating circuit sealed up and a filling loop and expansion vessel installed. A magnaclean would also be worth considering.
Obviously, pressurising a vented circuit comes with leak risks but a power flush would find those anyway!
 
Obviously, pressurising a vented circuit comes with leak risks but a power flush would find those anyway!

Not nexxessrily. A PF will clean out gunk that may be plugging a hole, whereas a rise in pressure wil blow through a vulnerble point. A PF Does not work at pressure, it is the velocity that does the work.
 
If you have a cheap boiler swap all done in one day then don't expect much power flushing. I would say that five hours is needed to power flush. But a power flush is not needed in all cases, if fairly clean then a chemical flush is usually adequate.

In addition to the words used to describe flushing above, its good practice to reverse the flow direction when each radiator is being flushed individually.

But there are so many variables according to the preferences of the engineer and what his equipment does and the type of dirt and chemicals used.

A common bodge is to fit a magnetic filter ( at customer's expense ) and do very little flushing. But in many cases no arrangements are put in place for cleaning the filter. They sometimes get completely clogged until the heating goes cold.

I suspect that all you may need are a chemical flush and proper balancing!

Tony
 
Thanks Tony - there IS a Magnaclean fitted - can they get so gunged up as to block the flow? - I thought they just didn't collect sludge so well if they were dirty. I did clean this last year when we had previous problems and it wasn't very dirty at all. But the boiler was apparently completely blocked up and corroded which is why we had to have a new one fitted. It was only 5 years old. Also, I assume that a Magnaclean will only collect ferrous sludge and not other detritus such as swarf and scale?
 
You never said what model of boiler you had fitted.

Was it a Heatline?

Tony
 
That's the problem with a Magnaclean that they primarily only collect magnetic dirt.

There can be a lot of other types of non magnetic dirt in a system.

Because I always properly clean a system then I don't see much need for a magnetic filter although a gauze filter is a fraction of the cost and stops any kind of dirt.

Tony
 

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