Raypak 538 To 4224 - Manual (Page 8)

9
PART 2 - SECTION I - INSTALLATION INSTRUCTIONS
PUMP SELECTION
The filtration pump must be sized to provide an
adequate water flow for the filtration system
and the heater. In some cases however, this
can cause a high back pressure which reduces
the filtration capacity and in this case it would
be more of on advantage to install an additional
pump for the heater only. This pump must be
installed on the inlet side.
DO NOT connect the pump to the heater outlet.
Some heater models incorporate their own By-
Pass Pump but this is used to control the
temperature of the water entering the heater to
prevent condensation and scale and will not be
suitable as the additional pump described above.
Refer to the Flow Rate chart following when
sizing the pump.
Where the water flow rate exceeds the
maximum shown in the chart, a by pass valve
must be installed to reduce the water flow
through the heater.
A pump run on timer must be fitted to remove
any residual heat from the boiler and prevent
any nuisance tripping of the high limit switch.