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Q.  Can I use a radiator valve change kit (= tapered 
rubber bung kit), used when changing radiators, to 
make the system a closed circuit for the power flush?

A.  No. The tapered bung inserted in the cold feed pipe 
will be forced out, and the expansion tank will fill up and 
overflow.

Q.  Can I use plastic or metal push fit caps, such as 
“Speedfit” fittings, to make the system a closed circuit?

A.  Yes, but check the push fit cap ‘O’ ring for wear 
regularly, and replace it if in doubt.

Q.  What do I do if the expansion pipe on an old system 
is imperial size copper piping?

A.  Why not extend the pipe slightly, using a compression 
fitting with a special imperial size olive, enabling you to 
add a short length of metric piping? Then use a push fit 
end cap as usual.

Q.  If I connect my Clearflow pump into the system 
across the tails of one (removed) radiator, what 
happens to that radiator? How should I clean it?

A.  You’ll need to flush this separately with a hose pipe 
(so pick a small radiator!). 
Alternatively, some engineers will adapt the outer end 
of their dump hose to fit onto one side of this removed 
radiator, with another adapted tube leading from the 

other side of the radiator to the drain. 

This way, every time you dump, you’re putting a good 
flow of water through the radiator. By the time you’ve 
finished the power flush, the radiator should be very 
clean.

Q. I want to keep my pump outside the house. Can I use 
extension hoses?

A. Yes you can, and we can supply any length extensions 
that you may wish, but we often supply an extra set of 5 
metre flow and return hoses, and send them out with a 
3/4” - 3/4” male nipple in one end of each hose.

 This means that when you need to extend flow and 
return hoses, you simply couple the new extension 
hoses onto your existing flow and return hoses, and if 
you sometimes need a longer dump hose, rather than 
longer flow and return hoses, the 2 x 5 metre lengths can 
be coupled together and added on to the existing dump 
hose. This gives flexibility without the need for a van full 

of hose.

Caution: longer hoses mean greater frictional losses, and 
so we suggest a maximum overall length of 12 metres 
per hose.

Q. Can you power flush a heating system with a thermal 
store type cylinder?

A. Yes. Our advice is to isolate the thermal store cylinder 
and flush the radiator and boiler circuits separately.
There are two reasons for this:
1. One cylinder manufacturer (Gledhill, though others 
may take a different view), advises that their cylinders 
shouldn’t be connected on the positive side of a pump 
that may provide more than one bar pressure.
Although that level of pressure on the cylinder is unlikely 
to be present anyway, we advise a cautious approach.

2. If you do include the thermal store in the power 
flushing circuit, then instead of pumping approximately 
100 or less litres of water around, you’ll be pumping 
around almost three times that, and so the vital overall 
flow rate will be much less than half – so not a good idea 

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Summary of Contents for CF210

Page 1: ...The Power Flushing Knowledge Base Frequently asked questions and their answers...

Page 2: ...3 How long will a power flush last Page 17 Imperial size pipework Page 5 Individual radiator dumping Page 14 Individual radiator flushing Page 14 Inhibitor used with soft water Page 16 Location of flu...

Page 3: ...me water out of a vented system to lower the water level in the feed and expansion tank so that you can cap it off Q Can you power flush a sealed system A You certainly can in fact you can ONLY power...

Page 4: ...e zone and collapse and it is the sound of the implosion of the steam bubble that you hear This phenomenon is most likely to occur when the boiler first fires and is working hard It is a reasonable as...

Page 5: ...e the house Can I use extension hoses A Yes you can and we can supply any length extensions that you may wish but we often supply an extra set of 5 metre flow and return hoses and send them out with a...

Page 6: ...Q Is there is another way to check if a cold feed pipe is blocked A When starting to set up for a power flush you ll normally cap off the cold feed and expansion pipes before anything else Don t Just...

Page 7: ...ators on the verge of failure with only a veneer of debris preventing leakage from deep pits in corroded areas and so your watchword is caution Q How often should I check the corrosion inhibitor level...

Page 8: ...hose connects into the system From that point on the pressure is falling away throughout the system until the point where the return hoses drops the water back into your power flushing pump tank where...

Page 9: ...ater through them High temperature resistant hoses can be fitted to a Clearflow pump but this type of plastic is not transparent and you d lose the advantage of being able to monitor water cleanliness...

Page 10: ...e air bubble in the cylinder leading to mixing of radiator and tap water The Primatic cylinder was usually gravity fed with separate pumped flow and return piping to the radiators Consequently connect...

Page 11: ...flush the system If you accept the job use HyperFlush instead of PowerFlush FX2 and always ask the householder to sign a disclaimer Q Are there any other systems I should treat with caution A Look ou...

Page 12: ...w can I remove it and prevent future problems A You need a specialist cleaner to break down and remove bacterial matter in heating systems Kamco Systemsafe Bio is the product to use Circulate it throu...

Page 13: ...ne direction If you can t find the non return valve which is very probable the flow reverser lever must be left in one direction Q I ve connected my Clearflow into a heating system made it into a seal...

Page 14: ...cal If you do you ll be dumping your flushing chemical straight down the drain and will have to keep adding more as you work your way around the house Whilst we think that this is an excellent idea fr...

Page 15: ...eading as possible and ideally within 5 10 of the reading obtained for tap water Another method is to use a turbidity tube to give a reading of suspended particulate matter in the dump water The turbi...

Page 16: ...al flow and hence the efficiency of the whole power flushing process Q I m working on a house with a water softener installed on the water supply Is there any problem if I fill the system with artific...

Page 17: ...all us to arrange collection Will power flushing damage the system Q Will power flushing cause damage to a heating system A It is rare for a heating system to experience leaks after the power flushing...

Page 18: ...n debris magnetite in the form of scale on the internal surfaces of pipe work and which has developed over many years Sometimes this hard scale will not be removed by a power flush but fortunately the...

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