6.2 Water connections
To connect the indirect hot water cylinder to the stove, use 28mm copper
pipes. Ensure that the pipes rise continuously to the cylinder.
Ensure that runs are not too long (i.e. 6 metre maximum each for flow and re-
turn). Install the cylinder above the level of the appliance and as close to it as
possible. Within reason the higher the cylinder the faster the circulation. En-
sure no valves are present in the pipes.
In addition to providing hot water the primary circuit is essential in providing a
’heat leak’ radiator to absorb excessive heat produced in the event of a circu-
lating pump shutting down.
Heat is produced in varying quantities while the stove is alight and care must
be taken to ensure that effective circulation can occur around the primary cir-
cuit to carry the heat away thus preventing boiling. The heat output of any radi-
ator installed as a ’heat leak’ should not be less than 10 percent of the
rated output of the appliance to which it is connected. It should not be fitted
with a control valve as it should never be turned off or down. The hot water
cylinder must be indirect with a minimum capacity of 110 litres conforming to
BS 1566 part 1.
A radiator of approximately 2m
2
surface area should be connected to the
primary circuit.
6.3 Safety Vent Circuit
This circuit (shown in Fig. 5 on the next page) consists of a cold feed pipe, a
separate expansion pipe and expansion tank. The possibility that water in the
stove boiler may boil can never be completely ruled out, and it is therefore vital
to ensure that cold water can be provided to the boiler and steam vented from
it at all times.
The use of an expansion tank is important. This should have a capacity of at
least 7 percent of the systems total water capacity. The cold water feed pipe
should be at least 22mm in diameter.
There must not be any shut-off valves in the circuit. Pipes should be run so as
to avoid air locks. A safety valve should be fitted into the expansion pipe close
to the boiler. The expansion pipe should not be branched off from the cold
water feed pipe to ensure that it cannot be blocked by any sediment matter
originating from the expansion tank.
Page 15
BK 680 Specific
ECOBOILER Cassette Installation Guide