17
De-commissioning Procedures
62
De-commissioning
Pr
ocedur
es
If the solar thermal system is to be
taken out of use – either temporarily or
for a longer period, the following
procedure should be followed.
17.1 System
Isolate the electrical supply to the solar
thermal system. Remove fuse from
fused isolator and lock off the isolator.
Where the solar thermal system uses a
twin (or triple) coil cylinder, switch off
the other heat source(s) to the cylinder,
e.g. gas or oil boiler, heat pump, etc.
Manually close any 2-port valves in
either the flow or return pipe(s) from
these auxiliary heat sources to the
cylinder coil(s).
Allow solar thermal system to cool
down. If necessary, draw off hot water
from storage cylinder to reduce solar
system temperature.
Once cool (i.e. <50°C), drain solar fluid
from the system, via system drain
cock(s), into a suitable container, e.g.
the plastic container(s) in which the
solar fluid is supplied.
If the system is to be taken out of use
permanently, or not to be used for
some time, shut off the incoming cold
water supply to the cylinder and drain
all the water from the cylinder via the
drain of cock in the cold supply to the
cylinder.
If the twin (or triple) coil cylinder is to be
used to provide hot water following
decommissioning of the solar thermal
system, re-open any 2-port valves in
either the flow and return pipe(s) from
the remaining heat source(s). Check
the settings of all cylinder controls
(control and overheat thermostats) and
heat source controls (temperature
controls and programmers). Switch on
the heat source(s) – gas or oil boiler,
heat pump, etc. to put the cylinder
back into operation.
17.2 Disposal of Solar fluid
The propylene glycol used in the Grant
pre-mixed solar thermal system fluid is
non-toxic and does not contain any
nitrates, phosphates or ammonia. Refer
to Section 14.3 for details of the Grant
solar fluid.
However, DO NOT dispose of the solar
fluid into household drainage system,
controlled water, or any other drainage
system, e.g. storm drain, sewers, etc.
ONLY dispose of used solar fluid (40%
propylene glycol/water solution) in
accordance with local regulations – i.e.
at a licensed recycling or disposal
centre. Check with you local authority
for details of disposal facilities in your
area.
17.3 Collectors
If the collectors are to be removed from
the roof, either temporarily or
permanently, a safe method of removal
must be employed for working at
height, e.g. a tower scaffold or
permanent scaffold.
After removal of the collectors, the roof
covering should be reinstated and
made weatherproof.
If the collectors are to be left in position
for a long period (in excess of 30 days),
with the system decommissioned and
drained of solar fluid, it is advisable to
cover them using Grant reflective solar
covers – Grant Ref.GS222002 (pack of
two).
WARNING
Before commencing any work on
a solar thermal system cover the
collectors and allow the system to
cool down. These covers should
be removed when the
decommissioning procedure is
completed.
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