Finish Thompson LS-55IIE - Manual (Page 24)

23
Advanced Troubleshooting Tips: LS-15E / LS-55E
WARNING :
Qualified electrical personnel must perform all electrical tests and work. There is a potential for sparks when the
electrical control box is open. The unit must be removed to a location outside the hazardous area before any
electrical work can be done on live circuits.
PROBLEM: No heat. Green light not on.
1. Verify that cooling water is properly supplied to the condenser. The unit requires at least 1-1/2 gallons per
minute for the LS-55 and 1/2 gallon per minute for the LS-15. Make sure this volume of water is passing
through the unit. If the water supply is not adequate the unit will not turn on.
2. Verify that the flow switch (FLS) is performing properly. Check for voltage between wire lL2 (on the on/off
switch) and wire 5 on pin 15 on the temp board. If no voltage exists, turn off your water supply and service the
flow switch (see pg. 17). It is located down low inside the front panel of the still (it is brass colored and labeled
"Gems" on it).
3. If after cleaning the flow switch (and turning the water supply back on) the voltage still is not present between
wire 1L2 and wire 5, temporarily bypass the flow switch by connecting a jumper wire between pin 21 and pin
15 (on the temp board) to see if the heater contactor engages. If the heater contactor engages with the flow
switch bypassed, replace the flow switch.
PROBLEM
: No heat. Green light is on.
The thermisters are metal rods that are inserted into the heater casting and wired to the temp board.
Their job is to tell the heater when to cycle on and off, using a temperature / resistance relationship.
Follow these instructions to test the thermisters (1 TC and 2TC) to verify proper specs.
1.
Disconnect the power to the unit.
2. Check each thermister individually by disconnecting their wires (22 gauge black and white twisted pairs) from
the temp board. One set is on pins 1 and 3, and the other set is on pins 2 and 4. Measure the resistance between
the black and white wires. The following values should be obtained;
Resistance
(kilo - ohms)
13 6 kΩ
90 kΩ
52.5 kΩ
3.9 kΩ Ambient Temperatures
(Degrees)
60°F (l6°C).
77ºF (25 °C).
100°F (38º C)
240°F (115°C)
If one or both of the readings do not fall within this range, the thermister(s) should be replaced. If they both
fall within acceptable ranges, continue with the troubleshooting tips.