flushing pump into circuit again.
4. This tip has been given to us by several of our
customers now, and we can’t guarantee that it will work
on every combination boiler. With some boilers it is
possible to fool the pressure sensor that stops the boiler
firing, by linking out the low pressure switch. You’ll need
to take all the normal precautions when working with
electricity (switch off first!), pull the wires off the water
pressure sensor (two) & link them together.
The boiler manufacturer technical department may be
able to confirm the success of the link out.
(Don’t forget to restore the correct wiring after the
power flush).
Other hot water issues
Q. Is it OK to dump very hot water from a heating
system down a drain or sewer?
A. There is a Public Health Act Regulation of 1936, which
states that water should not be discharged down a public
sewer at a temperature greater than 43
o
C, but in reality
this is unlikely to be a problem when power flushing.
However, do consider the risk of cracking a toilet pan
if you discharge very hot water into it when power
flushing.
Q. Why shouldn’t I use a CLEARFLOW pump with
scalding hot water?
A. A Clearflow pump may need to be used with very
strong chemicals, such as neat hydrochloric acid, when
being used for descaling. To enable this, all wetted parts
are either plastic, or are sleeved in plastic, and this
imposes a temperature limitation.
At high temperatures the clear plastic flow and return
hoses will become very flexible and may kink, so don’t
put scalding water 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 by
viewing the water as it travels through the pipes.
Remember that working with scalding water above 65
o
C
poses risks to you!
Q. What do I do if I arrive at a house where the heating
has been working, and the water temperature is above
70
o
C? Do I have to wait for the water to cool down?
A. No. Once you have connected the Clearflow power
flushing pump into the system, and connected all hoses,
immediately set the valves into the dump mode (dump
valve open), and then switch on. Run and dump for a
couple of minutes, allowing cold water in to the system,
before reverting to the normal flushing procedure.
Tricky systems to power flush!
Q. Can you power flush a microbore system?
A. Yes, but connection of the Clearflow pump should
be on to the circulator pump fittings, and not on to a
radiator, otherwise the small bore tubing will drastically
reduce the flow rate, and the system power flush will
be less successful than normal. We advise using 5 litres
of FX2 (instead of the usual 2.5 litres), to ensure the
particles of debris are dispersed in as fine a form as
possible.
If you can’t clear a radiator on a microbore system, it
may be that a plug of sludge is blocking the narrow
diameter pipework leading back to the manifold. If you
have a Kamco Systemsure IK6 injector, the following can
be worth trying to restore flow to the radiator.
Switch off and isolate the Clearflow pump. Close both
valves on the problem radiator. Attach the injector unit
to the air bleed screw fitting, and pump up the pressure
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