EcoSmart ES50HVP Service Manual - Thermostat Call Error
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Thermostat call error
If the ecosmart does not run when the thermostat is calling, jumper R to W for heating or R to Y
(Y2) to verify if the problem is with the thermostat or ecosmart control. Note that some
thermostats have a delay (typically five minutes) before they will re-start cooling to prevent
compressor damage.
Fan not running
The fan is driven by a variable speed EC motor. The PWM (Pulse Width Modulation) signal
generated by the control board at connector (19) has a frequency of 80Hz and an amplitude of
24V and can provide up to 64 speed settings (0 to 100% duty). To determine if the fault is with
the control board or the motor, use PWM tester P/N 22014. This tester has a single LED which
lights dimly for lower duty cycles and brighter for higher duty cycles. No light indicates a faulty
control board. To test, follow these steps:
1. Apply power and check for 120VAC on power connector at motor
2. If power is not present check door switch (13)
3. If power is still not present, check continuity of motor power cable
4. Unplug motor control cable at connector (19)
5. Connect PWM tester to the control board EC motor connector (19) with same
orientation as motor control cable
6. Jumper R to G to bring on fan
7. The PWM tester should gradually increase in brightness indicating that a PWM signal is
present. No light on the PWM tester indicates a faulty control board
Fan runs for cooling but not for heating
The room thermostat may be connected improperly. Refer to Electrical section or wiring
schematic on ecosmart for proper installation.
External pump does not run (sticking issue)
In areas where hard water is present the pump may stick and fail to run. Often, closing the
isolation valve on the return leg and opening the drain port so that water flows through the
pump can free this. If this fails to free the pump, removal for cleaning or replacement is
necessary. The daily pump exerciser will help prevent pump sticking.