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Control Description The Boiler Reset Module 420 provides outdoor reset to a hydronic heating system in order to maximize comfort and efficiency. The 420 can operate a single on / off boiler or a single modulating boiler. The 420 can override the outdoor reset water temperature to provide Domestic Hot Water or Setpoint operations.

Control Microprocessor PID control; This is not a safety (limit) control
Packaged Weight 1.7 lb. (771 g)
Dimensions 3-5/8" H x 5-3/8" W x 9/16" D (92 x 137 x 14 mm)
Approvals CSA C US, CSA/UL 61010-1, meets Class B: ICES and FCC Part 15
Ambient Conditions Indoor use only, 32 to 122¼F (0 to 50¼C).
RH equal to or less than 80% to 88¼F (31¼C), down to 50% from 104 to 122¼F (40 to 50¼C)
Altitude <2000 m, Installation Category II, Pollution Category 2
Power Supply Provided by interconnected Zone Manager
DHW Pump Relay 115 V (ac) 5 A 1/4 hp, pilot duty 240 VA
Primary Pump Relay 115 V (ac) 5 A 1/4 hp, pilot duty 240 VA
Combined Load 10 A Maximum (for DHW and Primary Pump)
DHW Zone Valve 24 V (ac) 8 VA Maximum
Modulation Output 0-10 V Minimum 2500 Ω
Boiler Relay 115 V (ac) 5 A 1/4 hp, pilot duty 240 VA
Demands 20-260 V (ac) / 0.1 VA @ 24 V
Sensors NTC thermistor, 10 kΩ @ 77¼F (25¼C ¼0.2¼C) +=3892
Included Outdoor Sensor 070 and Universal Sensor 071
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Boiler Reset
Width (Inches):
1 Boiler
User Interface:
Push Button
Depth (Inches):
Ambient Conditions:
Indoor Only: 32°-122°F RH equal to or less than 80% to 88F;50% from 104-122F Altitude<2000m
Power Supply:
From Interconnected Zone Manager
115 V (ac) 5 A-1/4 hp- pilot duty 240 VA;10 A Maximum
Min Temp (F):
Max Temp (F):
Temperature Range (F):
-76°F - 266°F
0-10 V Minimum 2500 Ohms
NTC Thermistor 10 k ohm @ 77°F
20-260 V (ac) / 0.1 VA @ 24 V
070 Sensor
071 Sensor
Weight (lbs):
1.75 lbs
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