F:\C - E\ECOMAX\COAL BOILER\Instructions and Manuals\Coal Boiler Manual Rev 6.doc
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Water Connection
The water system for the Coal Boiler must be a sealed, pressurised system. It must be
sized appropriately for the dwelling and the expected heating load it will carry by a
suitably qualified person. The expansion vessel should be at least 10% of the total
volume of the system. The Coal Boiler contains 34 litres of water, not including
external pipework. The flow and return connections on the rear of the appliance are
¾” BSP female threads.
DO NOT use an open vented system with a header tank, as this allows boiling of the
water and a continuous supply of oxygen into the system, which will corrode the
internal surfaces of the Coal Boiler & radiators.
The water system must be fitted with an air vent, or vents, to bleed the system on
filling, as well as a pressure relief valve. The pressure relief valve must be vented to
an area such that, if it was to relieve, could not cause damage to people or property.
Ideally this would be somewhere outside.
The first two metres of pipework to and from the appliance must be in a high
temperature resistant material such as copper. This is to protect the pipework from
possible damage from over-temperature in the unlikely event of a power cut.
For the rest of the water piping, pipe made from material that has an oxygen barrier
must be used, as internal corrosion of the Coal Boiler could otherwise occur. A rust
inhibitor must be used to treat the water and prevent internal corrosion.
A draining valve should be fitted at the lowest point for servicing. The best type of
valve is one in which the handle is removed so the system cannot be drained
accidently. Pipe thermometers should be fitted to both the flow and return pipes so
that the operator can check that the flow and return temperatures are not too low. The
return should not be below 55°C when the pump is running. If the return water is too
low, it is possible that the heating load & heat loss in the pipework has been
underestimated, and the appliance will not be able to heat it.
It is recommended that an isolating valve be fitted on both the flow and return lines at
the boiler connection to make future servicing significantly easier. The pump should
also have isolating valves either side.
The plumbing work must be carried out in a proficient manner and be free of leaks. If
the system needed regular topping up with fresh water due to leaks, oxygen would be
introduced and internal corrosion of the Coal Boiler and radiators would occur.
The Coal Boiler requires a suitable pump to be installed, appropriately sized by the
installer. The pump should be installed as per the pump manufacturer’s instructions. It
must be electrically connected to the Coal Boiler via the connector inside the rear
panel of the appliance. The Coal Boiler will switch the pump on and off depending on
