Wiring; Wiring The Power (Terminals 1, 2); Wiring The Sensors; Wiring The Shutdown (Terminals 31, 32) - heat-timer Mini-Extension Installation And Operations

WIRING

WIRING THE POWER (TERMINALS 1, 2)

• Bring the 120VAC 60Hz power wires through the bottom Knockout of the enclosure.
• Class 1 voltages must enter the enclosure through a different opening from any Class 2 voltage wiring.
• Connect the hot line to terminal marked L.
• Connect the neutral line to the terminal marked N.
• Heat-Timer recommends installing a surge suppressor on the power source to the Mini-MOD.
Class 1 voltages must enter the enclosure through a different opening from any Class 2 voltage wiring.
Heat-Timer recommends installing a surge suppressor on the power source to the Mini-MOD.
Connect the shield at the control terminal end and cut the shield wire at the sensor end.

WIRING THE SENSORS

SYSTEM SENSOR WIRING (TERMINALS 27, 28)
• A Mini-MOD must be connected to a temperature sensor located in the common header.
• The Mini-MOD is designed to be connected to a HT #904015-00 temperature sensor for immersion in a
3/8ID well (HT #350147-00 or equivalent). Contact the factory for additional temperature sensor options.
• Temperature sensor wires can be extended up to 500' by splicing shielded 2-
conductor cable (Belden #8760 or equivalent).
• Temperature sensors have no polarity. Connect the two wires from the sensor
to the Mini-MOD terminals marked SYSTEM TEMP 27, 28.
• Connect the sensor shield to the circled terminal 28 with one of the sensor wires.
OUTDOOR SENSOR WIRING (TERMINALS 25, 26)
• When Outdoor Reset is selected, the Mini-MOD will vary the system Set Point based on outdoor temperature.
• Whether in Set Point or Outdoor Reset modes, the outdoor sensor can be used as an Outdoor Cutoff.
The Mini-MOD will disable all Boilers when the outdoor temperature is above the adjustable Outdoor
Cutoff temperature. This feature will automatically be activated when an outdoor sensor is connected.
• For an outdoor sensor use a Heat-Timer outdoor sensor (HT #904015).
• The sensor wires can be extended up to 500' using shielded 2-conductor cable (Belden #8760 or equivalent).
• Temperature sensors have no polarity. Connect the wires from the outdoor sensor
to the Mini-MOD terminals marked OUTDOOR TEMP - 25, 26.
• Connect the shield to the circled terminal 26 with one of the sensor wires.

WIRING THE SHUTDOWN (TERMINALS 31, 32)

• This feature can be used whenever it is desirable to turn off the Mini-MOD stage outputs from a remote
location or another controller (i.e. EMS input).
• When the Shutdown feature is enabled by closing a dry contact, all active boilers will immediately modulate
down to low then off. The lead boiler will remain in low for a Soft-Off period; default setting is 45 seconds,
and then turn off.
• The System Output relay will remain active until the System Delay is over and then it will turn off.
• The Shutdown signal must be a dry contact only. No voltage can be placed across the SHUTDOWN terminals.
• Bring the two wires from the dry contact to the terminals marked SHUTDOWN- 31,32.
Mini-MOD & Mini-Extension Installation Manual
WARNING
WARNING
9