HAMWORTHY HEATING LTD
11
WEYMOUTH
500001112/C
7.7.1 Pressure Switch Adjustment Apparatus
When adjusting pressure switches the unit must be set up with the apparatus similar to that shown in Figure 17
connected to the outlet.
Figure 17. Pressure Switch Adjustment Apparatus
7.7.2 Cold Fill Pressure Switch
Designed to stop the pump when pressure reaches a preset level. Setting procedure as follows:
1). Ensure the system pressure is lower than the pressure the switch is to be set to.
2). Switch the unit on.
3) Introduce a small leak at the outlet.
4) Because of the leak the unit begins a cycle of starting and stopping. Adjust the cold fill pressure switch until the
starts at 0.4 bar below the required cold fill pressure.
7.7.3 Lo Pressure Switch (Advanced Only)
Designed to stop the boiler operating if the pressure falls below a preset level. Setting procedure as follows:
1) Set the cold fill pressure switch by following the procedure in section 7.7.2 & allow system to run to pressure.
2) Isolate the Weymouth unit from the mains electrical supply & from the boiler circuits
3) Introduce a small leak until the unit’s pressure gauge reading equals the required Lo pressure setting.
4) Stop the leak.
5) The lo pressure switch is lowest on the panel which pivots around corner for easy access (see figure 23).
7) Set the lo pressure switch to its highest level (adjustment is shown in fig 16)
8) The terminals at either end of the switch form a closed circuit. Adjust the switch until the circuit is open . A
meter across the two terminals will signal the change.
7.7.4 Hi Pressure Switch (Advanced Only)
Designed to stop the boiler operating if the pressure exceeds a preset level. Setting procedure follows:
1) Isolate the Weymouth unit from the mains electrical supply & boiler circuits.
2) Use the pressure source increase the pressure until the pressure gauge reads the required Hi pressure level.
3) Set the hi pressure switch to its lowest level (adjustment is shown in fig 16).
4) The terminals at either end of the switch form an open circuit. Adjust the until the circuit is closed. A meter
across the terminals will signal a change.
If needed figure 25 shows the wire colours of the switches.
