Determining Water Flow - Calorex Pro-Pac Series Owners & Installation Manual

PR0-PAC SYSTEM OWNER INSTALLATION MANUAL

4. DETERMINING WATER FLOW

a) Flow Meter Method (see fig 3.)
Ensure isolation valves 'A' and 'B' and bypass valve 'C' are fully open.
Slowly close down bypass valve 'C' until correct flow rate (see data
sheets) is shown on the flow meter. Remove handle and lock off valve
'C'.
b) Differential Pressure Method (see fig 3).
By simply installing two filter pressure indicating gauges, one each on
the inlet and outlet of the heat pump, and a locking type gate bypass
valve in the bypass line, the flow rate through the heat pump can be
accurately determined by the difference in the readings of the gauges.
This pressure drop is proportional to flow.
Flow rate should be set at the maximum differential with a clean filter
if fitted. this differential pressure will drop as the filter becomes dirty.
Provided the filter is cleaned before the minimum differential is reached
(which would normally be the case with a well managed system) then
no problems should be encountered.
Setting up the differential
When the installation is complete, the procedure for setting the flow
rate through the heat pump using two gauges is as follows:
1. With the heat pump switched off, ensure isolation valves 'A', 'B'
and bypass valve 'C' are fully open.
2. Switch on water circulating pump.
3. Note the water system pressure on both gauges - they should read
the same, but because of manufacturing tolerance they may read
different.
For example – with a water system pressure of 5mhd the gauge
on the inlet may read 5 and the outlet gauge 5·5 therefore there is
a STATIC ERROR DIFFERENCE of 0·5mhd.
4. Gradually close the bypass valve 'C' until there is a difference in
pressure between the two gauges that is equal to the required
pressure drop (see data sheets) observing any static error on the
gauges before beginning this process.
5. Lock the bypass valve, or render it tamper proof, when correct
setting is achieved.
6. See data sheets for correct pool water pressure drop.
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SD566250 ISSUE 35