MAU Installation Manual
Page
17
LOW VOLTAGE CONTROL WIRING
The King MAU has a built-in relay logic control circuit enabling other make up air components to
be controlled directly by the MAU. Review all the system components such as the damper, exhaust
fans, outside thermostat and humidistat. All the control options are prewired to a 14-point
terminal strip making them easy to integrate by the installer. The control circuit does not require
any programming, simply enabled the control features by wiring the external components directly
to the MAU low voltage terminal strip. List of control features:
1.
R1-R2, ON/OFF control of the MAU. Closing this circuit via a dry contact will turn on the fan
and the modulating heating circuit. This is often done by a building management system,
but other common methods are to be activated by a current transformer (CT) on an exhaust
fan, a timer, or a manual switch. Once on, the Solid-State Relay (SSR) regulates the wattage
to the heating elements to accurately control the discharge air temperature from the MAU
regardless of the incoming outdoor air temperature.
2.
A0, proportional signal from the built-in thermostat (0-10VDC) that drives the SSR to
modulate the heat output.
3.
DS-DS, DUCT SENSOR, the field installed duct sensor is connected to thermostat for
controlling and maintaining the output temperature, type 2 NTC thermistor, 10K ohms.
4.
24V HOT - 24V COM, these are the 24VAC connections to the modulating thermostat.
5.
L-L, LOCKOUT CIRCUIT, the controller can be wired to an optional outdoor thermostat and/or
a humidistat by using the ‘L-L’ terminals to prevent the MUA form turning on. Remove the
factory set jumper to activate this feature. This feature can also be used to monitor indoor
activity such as an occupancy sensor and CO2 sensor.
6.
G, FAN ONLY, closing G-R1 will turn on the fan and bypass the modulating heating circuit.
No heat in this mode.
7.
EF-EF, EXHAUST FAN, provides a switched 24VAC circuit to connect a fan relay that will turn
on an exhaust fan relay or other auxiliary device.
8.
D-D, DAMPER, provides a switched 24VAC circuit to connect to a motorized damper with
spring return. Note: 40VA maximum for the sum of EF-EF and D-D.
Note: If the design calls for a room thermostat, the inbuilt thermostat and duct sensor can be
removed. Place the thermostat in the new room location and extend the wiring connections form
the MAU low voltage terminal strip, connect A0 on the terminal strip to AO 2 on the thermostat
when used as a room thermostat without a duct sensor.
