Installation manual

16
TWIN FLOW CENTRAL HEATING PIPEWORK
The central heating pump within the boiler has an available external head of 17kPa.
The water heater must have an isolating valve (supplied with the Twin Flow) and
union connection for removal of the appliance on the hot water supply.
ADDITIONAL PUMP / LOW LOSS HEADER
If it is found that the system resistance is greater than the working head of the pump
installed within the boiler, an additional pump may be fitted to the primary flow pipe
from the boiler. This must be installed after a permanently open by pass, with a
minimum size of 28mm. If the primary pipework is greater than the boiler connection,
then the by pass should be sized one size greater than that of the installed service.
It is possible to install the boiler on a low loss header. This will improve the
performance of the unit, as the flow rates through the heating circuit do not influence
the flow rates through the boiler, this will however result in the internal pump working
as a shunt pump. An additional pump must be installed to the primary flow to the
heating circuit after the header.
Heating Flow Heating Return
Water Heater Boiler