
WALL-MOUNTED THERMOSTAT CONTROLS
For 52C,P wall thermostat control (RC, RP) units, all controls are located on the
| R | R |
| G | G |
TYPICAL | Y | Y |
WALL |
|
|
THERMOSTAT | W | W |
| O | O |
| C | C |
TERMINAL
BLOCK
See Figures
A field conversion kit is available to convert an AA model (standard
IMPORTANT: No conversion kit is available to convert from an RC model back to an AA model.
TERMINAL | DESIGNATION |
R | 24 VAC |
G | Fan |
Y | Compressor |
W | Electric Heat |
O | Reversing Valve |
C | Common |
NOTES:
1.Use terminal “O” for heat pump con- nection only.
2.See table at left for terminal descriptions.
3.Common wire “C” is typically used only for digital thermostats.
4.Power stealing is NOT allowed. There must always be a hard common connec- tion between unit and digital thermostat.
FIGURE 38 — NON-PROGRAMMABLE
THERMOSTAT
FIGURE 39 — MANUAL THERMOSTAT
FIGURE 40 — PROGRAMMABLE THERMOSTAT
FIGURE 41 — WIRING CONNECTIONS
REMOTE THERMOSTAT
TROUBLESHOOTING
Thermostat display is blank:
Check to make sure there is 24 VAC to the thermostat (measure across terminals R and C at the thermostat). If there is 24 VAC at the thermostat, check connec- tions at the thermostat terminal block. If connections are good and there is 24 VAC with no display, the ther- mostat should be replaced.
Thermostat display is working but unit is not heating or cooling:
At the RC terminal block on the unit, measure the con- trol inputs coming from the thermostat. (Place one of the meter leads on C and use the other to check the voltage at each of the terminals.)
|
|
| TERMINAL |
| ||
MODE |
| METER READINGS (VAC) | ||||
R | G | Y | W | O (For | ||
| ||||||
| HP Only) | |||||
|
|
|
|
| ||
Fan Only | 24 | 24 | 0 | 0 | 0 | |
Cooling | 24 | 24 | 24 | 0 | 24 | |
Heating |
|
|
|
|
| |
Heat Pump Unit | 24 | 24 | 24 | 0/24* | 0 | |
Heat/Cool Unit | 24 | 24 | 0 | 24 | 0 |
*24 VAC supplied if thermostat is in 2nd stage heating demand (large difference between room temperature and setpoint).
NOTE: For heat pump units, the Outdoor Frost Thermostat (OFT) will determine, based on outdoor temperature, whether to bring on the com- pressor or electric heat in the Heating mode.
FIGURE 42 — THERMOSTAT TROUBLESHOOTING
If the inputs are not correct, then the thermostat is not making a call for the mode requested. This could be because the thermostat is in a unit protection mode, not set up properly, miswired, has a broken wire, or it may have failed.
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