Two-Speed Control Manual Override - Lennox HP21 Unit Information

TABLE 3
Compressor Winding
Temperature Sensor
TSC−2 Bristol or Copeland
Compressor

Two-Speed Control Manual Override

The manual override button is designed to be an aid in ser-
vicing and troubleshooting the control or the unit. When the
button is pushed and then released, the control bypasses
the five minute override delay.
TABLE 4
COMPRESSOR WINDING SENSOR
OPERATING RANGE
Resistance Through
Compressor Winding
Temperature Sensor
K-ohms (ohms x 1000)
0
1.0
5.5
6.9
8.4
10.0
16.0
20.0
24.0
25.0
30.0
35.0
− +
DC volts
Measured with unit running.
Do not use the override button for eleven seconds after
power-up. If the button is pushed during the ten second
power-up delay, the button has no effect. The control com-
pletes the five minute delay.
LED OFF"
MAY MEAN UNIT FAULT" CONDITION
If the unit will not run and the LED is not lit, a unit lockout
condition is indicated. Breaking and remaking thermostat
demand will reset the control. Activate the compressor by
pressing and releasing the override button (see illustra-
Trip Ohms Reset Ohms
Temp. Rise Temp. Fall
25K to 35K 8.4K to 10K
Voltage Across TSC Ter-
minals S1 and S2 with
Unit Running
DC Volts +.15
.02
.92
3.4
3.9
4.3
Reset
4.7
Range
5.6
6.0
---
6.3
Trip
6.8
Range
7.0
Page 9
tion). If compressor starts, the control is good and should
not be replaced. Proceed through the troubleshooting flow-
chart in the Unit Information Manual to locate the source of
the lockout. If the compressor does not start, a problem
probably exists elsewhere in the unit. Check the unit volt-
age and proceed through the unit troubleshooting
flowchart in the Unit Information Manual.
LED ON"
MEANS TSC FAULT" CONDITION
If the unit will not run and the LED is lit, the TSC may be in
Safety Dormant Lockout (a lockout caused by self-test fail-
ure or high voltage spike).
To determine if the control is in Safety Dormant Lockout,
briefly turn off power at the disconnect. When power is re-
stored, check the LED. If the LED is lit, the control is
damaged and must be replaced. If the LED is not lit, the
control is probably good and should not be replaced until
eliminated by all other checks. Confirm this by activating
the compressor (press and release the override button with
thermostat demand present). If the compressor starts, the
control was in safety dormant lockout (due to high voltage
spike or self-test failure) and the control should not be re-
placed. If the compressor does not start, the control is
probably good and the problem is located elsewhere in the
unit. Proceed through the troubleshooting flowchart to lo-
cate the problem. Start by checking all manually reset
controls (high pressure switch etc...)
Service Instructions:
1− If light comes on and stays lit, turn off power at dis-
connect for at least 3 seconds.
NOTE−Breaking thermostat demand will not reset the
control if the control is in a Safety Dormant Lockout.
2− If LED is on when power is restored, replace TSC.
3− If light goes out see troubleshooting flowchart in
Unit Information Manual.