Huntleigh AlphaBed, Service Manual

Page: 72 / 94

4 Low Pressure Alarm Fault
If the low pressure alarm does not function correctly after recalibration as described in Chap. 5
(Testing), check:
4.1 The electrical connections and leads between the low pressure micro-switch and the printed
circuit board.
4.2 Check that switch is operating and n/o terminals (1-3) are in use.
4.3 Check free movement of lower flap.
4.4 Check low pressure switching point with an external pressure meter.
4.5 Check the pressure control module for leaks.
4.6 Check the location and orientation of low pressure spring and disc by removing upper and
lower flaps.
5 Air Not Alternating (continuous pressure fault)
Should the cells of the mattress not inflate and deflate during a 10-minute cycle, then the timer motor
may be defective (not rotating).
5.1 Check the timer motor electrical connections for security and integrity. If all are sound and the
timer motor still does not rotate, then the timer motor must be replaced.
Notes : The timer motor is a sealed unit and cannot be repaired.
When replacing the timer motor it is advisable to replace the stator gasket at the same
time. Refer to Chap. 3 (Pump Repair).
6 Loss of Electrical Power
Power loss can be due to any of the following:
6.1 No electricity supply at wall socket.
6.2 Faulty wall socket.
6.3 Damaged plug or mains/power cable.
6.4 Defective fuse link in pump or plug.
6.5 Damaged internal wiring.
6.6 Loose connections at the terminal block, micro-switch or PCB.
6.7 Faulty PCB component.
Chap 4 Issue 2
Page 4 SER0004 Nov 2001
Troubleshooting Mini Pump Service Manual