Honeywell Home ERM5220R Guide D'installation page 5

TERMINAL DESIGNATIONS FOR BOILER
TERMINALS FOR C7189U1005 10K OHM TEMPERATURE SENSOR. CAN BE USED FOR FREEZE PROTECTION
IN THE CASE OF THE THERMOSTAT LOSING THE SIGNAL TO THE ERM. SENSOR MUST REMAIN INDOORS TO BE
USED FOR FREEZE PROTECTION.
TERMINAL FOR HEAT CALL.
TERMINAL FOR HEAT CALL.
TERMINALS FOR 24VAC POWER.
TERMINAL FOR JUMPER. JUMPER BETWEEN J AND R SHOULD BE REMOVED FOR BOILER USE.
NOTE: ERM WILL NOT SUPPORT SERIES 20 OPERATION. WHEN CONFIGURED AS A BOILER, THE Y RELAY SHALL BE OFF AT ALL TIMES.
M35656A