Edwards 30B5M, Instruction Manual, Page: 32 / 50

B064-04-880 Issue F
Page 24 © Edwards Limited 2008. All rights reserved.
Edwards and the Edwards logo are trademarks of Edwards Limited.
Operation
4.4 Adjust the boiler protection thermal snap-switches
CAUTION
Ensure that the boiler protection thermal snap-switches are correctly adjusted when the pump is fully charged
with fluid and under vacuum. If they are not, the pump may overheat and the boiler may implode.
As supplied, the boiler protection thermal snap-switches ( Figure 1 , item 12) are set to operate to shut down the pump
when the boiler temperature reaches 250 ºC. If you need to adjust the snap-switches to operate at a different
temperature, use the following procedure. You must adjust the thermal snap-switches when the pump is fully
charged with fluid, is at operating temperature and is under vacuum; if you do not, the snap-switches may not
operate at the correct temperature, and the pump may overheat.
1. Remove the boiler end-cover at the control-box end of the pump.
2. Refer to Figure 8 . Loosen the locking screw (3) on the snap-switch.
3. Slowly turn the temperature set-screw (2) clockwise until the snap-switch just trips open; the pump will then
automatically shut down.
4. Turn the set-screw anticlockwise again by ¾ of turn (270º); one complete anticlockwise revolution of the screw
(in the direction of the arrow, 4) is equivalent to an increase in the operating temperature of approximately
40 ºC.
5. When you have set the snap-switch, tighten the locking screw (3).
6. Refit the boiler end-cover.
7. Restart the pump: refer to Section 4.5 .
8. Remove the boiler end-cover at the drain-plug end of the pump.
9. Adjust the other thermal snap-switch: use the method in Steps 2 to 7.
4.5 Pump start-up after over-temperature shut-down
If the pump has been shut-down automatically because of an over-temperature fault (that is, the thermal snap-
switches have operated to switch off the electrical supply to the heaters), you must manually restart the pump. Use
the following procedure:
1. Allow the pump to cool down to its normal operating temperature.
2. On unconfigured pumps, switch on the electrical supply to the pump.
On control configured pumps:

Press the Power Enable switch on the control-box ( Figure 2 , item 1) and make sure that the Power Enable
lamp ( Figure 2 , item 2) goes on.

Set the Heater Power switch ( Figure 2 , item 3) to the required operating mode (half-heat or full-heat)