Outdoor Sensor; Pressure Or Vacuum System Transducer; Wiring The Setback/Boost; Wiring The Enable/Disable - heat-timer DIGI-SPAN Elite MC Series Installation And Operation Manual

strap-On heating system sensor Installation
• Strap the sensor to the pipe. Make sure that the sensors concave surface
matches the pipes concave surface.
• Strap pipe insulation around the sensor and pipe.
• Use plastic tie-wraps to hold the insulation and sensor to the pipe.
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DO NOT place any voltage on any of the input terminals.

Outdoor sensor

Terminals (T2, COM)
• The Outdoor Sensor must be used when Outdoor Reset is selected as the
Control Mode from the Startup menu. However, in Set Point mode, the
Outdoor Sensor is optional. In this mode it will be used for the outdoor Cutoff.
• Only use the Heat-Timer outdoor sensor (HT# 904220-00).
• Place the sensor in the shade on the north side of the building at least 10'
above the ground.
• Be sure the location is away from any heat or cool sources.
• Adhere the Outdoor Label provided to the back of the sensor base.
• Use the Enclosure Base bottom knockout for the conduit. Use the locknut to
hold the conduit and enclosure base together. Screw the cover to the base.
• The sensor wires can be extended up to 500' using a shielded 2-conductor 18
AWG cable (Belden #8760 or equivalent).
• Cut the shield and do not connect it at the sensor end. Only connect it at the
control end using any of the COM input terminals.

pressure or vacuum system transducer

Terminals (P+, P-)
• Select a sensor location that is representative of the entire system. Place the
Pressure Transducer in the common header where it will register the output of
the boiler/valve before any takeoffs.
• Set the Sensor Type to match the Transducer and system used.
• Attach a 1/4" brass isolation tube (pigtail) to the steam/vacuum header.
• Screw the pressure or Vacuum sensor to the pigtail.
• Connect the sensor's Red wire to the MC Elite terminal marked P+.
• Connect the sensor's Black wire to the MC Elite terminal marked P-.
• The sensor wires can be extended up to 500' by splicing with 18 gauge
twisted pair cable.

Wiring the setback/Boost

Terminals (T3+, T3-)
• The Setback feature can be used to provide the MC Elite with a lower Set
Point when less output is required during night or unoccupied periods.
• The Setback is activated by closing/shorting the T3+ and T3- terminals using
an external control, i.e., timer, control, or switch.
• The MC Elite accepts dry-contact input signals only.

Wiring the Enable/Disable

Terminals (EXT+, EXT-)
• The EXT+ and EXT- terminals are used to enable the system by connecting it
to a thermostat, switch, or an external control.
• The controls requires these terminals to be shorted to operate the outputs. If
no thermostat or control is connected to the EXT+ and EXT- terminals, leave
the jumper supplied as a dry-contact to the terminals.
MC-Elite Installation and Operation Manual
Strap-On Temperature Sensor
Common Supply Pipe Insulation
Pipe
Shield
Connect
To control
Seal around
sensor and wall
Mounting
screws
location
Outdoor
drip-hole
T2 COM T3+ T3- EXT+EXT-
Cut the Green,
White, and Clear
Tube
Connect
to 1/4" pigtail
T1 COM T2 COM T3+ T3-
Setback
ALErt
The EXT± input terminals must be
shorted for the MC Elite to operate.
DO NOT remove the factory installed
EXT jumper unless it is replaced with
an Enable Signal.
Sensor Probe
Outdoor Sensor
snap-in location
Shield
not connected
Outdoor Label
on back of Sensor
Conduit
P+ P- COM24VAC
EXT+EXT- P+ P- COM24V
Enable/Disable
Switch
7