Finish Thompson LS-55IIE User Manual
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Advanced Troubleshooting Tips: LS-15E / LS-55E continued…
3. Verify that the K2 relay on the temp board is closing (when unit is turned on) by measuring for voltage between
wire IL2 (on the on/off switch) and wire 6 on pin 14 (on temp board). If no voltage is present, K2 may be faulty
and the temp board must be replaced. If 240V is present, K2 has closed and it is all right to continue with
troubleshooting tips.
4. Verify that KI relay on the temp board is closing (when the unit is turned on) by measuring for voltage between
wire lL2 (on the on/off switch) and wire 7 on pin 11 (on temp board). If no voltage is present, and all previous
tests check out, K I may be faulty and the temp board must be replaced. If 240V is present, Kl is closed and the
temp board is alright. If the temp board checks out, call the factory for further information.
5. This set of troubleshooting tips will verify a faulty temp board. Most heating problems lie within the water
supply or the flow switch. It is common for scale and other debris to build up in this switch causing the
symptoms you are experiencing. A Y-strainer should be used on the incoming water supply to help prevent
problems.
If you have any questions, please contact our Technical Service Hotline at 800-888-3743.