What flushing chemical should you use?
The possibilities are:
1. ‘NONE’, accepting that you won’t be able to carry out
a very efficient power flush but you won’t have to worry
about the effects of any chemical on the bacteria in the
septic tank.
2. Use PowerFlush FX2, carrying out the normal
flushing procedure as usual until you have put the full
flow through each radiator in turn. Instead of then
commencing to dump on each radiator in turn, carefully
start adding Neutralising Crystals into the power flushing
tank to neutralise all the acidity before you begin to
dump on each radiator. Check the pH regularly until the
water is back up to a pH of 7.
What about the contaminated waste water, containing
quantities of iron oxides?
You can minimise the amount
of corrosion debris going down
the drain by using a Combimag
power flushing filter (two would
be better!), and we strongly
recommend that any power flush on
a septic tank dwelling should use a
CombiMag.
If the householder has concerns about the debris
entering the septic tank, then consider taking a 200 litre
barrel on site, and using that to take the waste water
away to where it can be disposed of down a foul water
drain.
It’s very probable that the total amount of water used
during the power flush will exceed 200 litres, and so
to minimise the amount of water to be taken off site,
consider only pumping into the barrel the first minutes
worth of dumped water from each radiator, as you
commence the ‘dump on each radiator’ procedure.
This obviously will be the most contaminated water.
Something puzzling is happening here!
Q. What happens if there is no apparent flow through
the CLEARFLOW unit when the flow reverser handle
is in one particular direction when I’m working on the
upstairs radiators?
A. If the system is a gravity hot water system, there is
probably an anti gravity / non return valve in the radiator
circuit. If the non return valve is accessible, either loop it
out, or remove the plunger so that it doesn’t prevent the
flow of water in one 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 sealed system, opened the isolating
valves, and switched on. The pump appears to be
working fine, but the water level in the Clearflow tank
is overflowing without the mains water inlet valve even
being open. What’s happening? Is there something
wrong with the Clearflow pump?
A. The answer is usually NO.
A1. This situation often occurs when for whatever reason
(perhaps a zone valve jammed by hard scale broken
loose from elsewhere in system, or complete blockage
in part of system, or even a sticking non-return / check
valve) your power flushing pump is running / rotating but
is not actually able to pump the water from its tank out
into the system i.e. no water is actually leaving the tank.
However, some system water will drain back down into
the tank through the ‘return’ hose under gravity, and so
the water level starts to rise.
(This occurs most often in a gravity hot water system,
or one that has at some time been converted from such
a system.) The solution is not always obvious, but you
need to check for any possible reason why the system is
choking off pump flow.
If you can’t locate the problem, you’ll have to point the
flow reverser lever in the opposite direction, and leave it
there.
A2. It’s less likely, but if it is a sealed system, there may
be an automatic pressurisation unit (sometimes known
as an autofiller) connected to the system, to maintain
the required pressure.
Switch it off, or it will be continually introducing more
water into the system to try to top up the pressure, and
as a side effect forcing water against the direction of flow
you need for a successful power flush.
Q. On some systems, when I am dumping the water
from the system, and I have used the boiler to heat the
water during the power flush, I notice that the radiators
are cold at the bottom, and warm at the top. What’s
happening?
A. A Clearflow pump circulates the water through a
system much faster than the standard system pump, and
it is the cool fresh water speeding straight across the
base of the radiator that you can feel.
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