Power Soak MX-220-HTS Owner's/Service Manual - Manual (Page 26)

25
Component Operation and Checks
Liquid Level Control and Sensor
The liquid level control sends a trickle current (1/1000 amp) out terminal 5 to the liquid
level sensor. If there is water in the wash sink, the current passes through it to the wash
sink wall and back to the liquid level sensor to terminal 6. On some machines, the wire
from terminal 6 is hooked up to a second probe instead of the wash sink wall. Reversing
these 2 wires will not affect the operation. After the circuit is complete, a 10 second time
delay is initiated. The purpose of this delay is to prevent rapid cycling of the relay should
the water rise and fall below the sensor while the sink is filling. At the end of the time
delay, the relay in the liquid level control will close sending current to operate the various
components in the control panel. If the red "power" light on the timer is on, the liquid level
control is ok.
On some models, the sensitivity of the liquid level control is adjustable. To adjust the
sensitivity, clean the liquid level sensor, TURN POWER OFF AT BREAKER PANEL and
check the resistance between the liquid level sensor and the wash sink wall (or second
probe). It should be 25,000 to 35,000 ohms. If not, adjust the sensitivity as required.
25,000 to 35,000 ohms is generally between 0 and 1 on the dial. If there is no resistance,
the wires from terminal 5 and 6 to the liquid level sensor and sink wall are loose, or the
liquid level control or socket is defective.
If adjusting the sensitivity setting does not allow the machine to operate, the liquid level
control can be checked as follows:
1. Set sensitivity as indicated above
2. Make sure wash sink is filled to the fill line. If the red "power" light on the timer is
on, the liquid level control is ok.
3. Remove liquid level control from socket.
4. Check voltage across terminals 2 and 7 of the socket and 1 and 7 of the socket. It
should be 208v-230v. If no voltage, check the breaker, fuses, and wiring to the
socket.
5. TURN POWER OFF AT BREAKER PANEL. Make sure there is continuity
between terminal 3 of the socket and terminal 4 on the heat on/off selector switch.
If not, trace the wire and make the necessary repair.
6. Reinstall the liquid level control. Wait 10 seconds and check the voltage across
terminal 4 on the heat on/off selector switch and L2 incoming power. If no voltage,
the liquid level control or socket is defective.