WattMaster MUA II - Manual (Page 21)

Technical Guide
MUA II Controller
21
Sequence of Operations
Initialization
On system power-up, a 30-second start-up delay is performed where
all default setpoints are initialized, LEDs are initialized, and all outputs
are turned off.
When power is fi rst applied, LED2 is turned off for 5 seconds. At this
time, the LED will “blink” to indicate the setting of the address switch
and then extinguish for another 5 seconds. The LED will now “blink”
for a 30-second start-up delay to protect the fan and other components
from short cycling during intermittent power conditions.
MUA II Confi guration & Setup
There are a few confi guration selections available to you which can be
used to tailor the software operation to match the mechanical equipment
this controller is installed on.
Resets
Supply Temperature Reset from Space Temperature
This feature requires a Space Temperature Sensor connected to the con-
troller. The reset is always upwards from the Supply Temp Setpoint to
the Maximum Supply temp (Maximum Supply temp = Supply Temp
Setpoint + Reset band). When the Space Temperature is at the Min
Temp Reset, the desired Supply temp is the Supply Temp Setpoint.
When the Space Temperature is at the Max Temp Reset, the desired
Supply temp is the Maximum Supply temp.
Outside Dewpoint Reset from Space Humidity
This feature requires a Space Humidity Sensor connected to the controller
on analog input AIN7. When this option is used, the Fan Proof of Flow
Switch option is not available as it also connects to analog input AIN7.
The reset is always downwards from the Outside Dewpoint Setpoint
to the Minimum Outside Dewpoint (Minimum Outside Dewpoint =
Outside Dewpoint Setpoint - Reset Band). When the Space Humidity
is at the Space Hum Min Reset, the desired Outside Dewpoint is the
Minimum Outside Dewpoint. When the Space Humidity is at the
Space Hum Max Reset, the desired Outside Dewpoint is the Outside
Dewpoint Setpoint.
Other Control Options
Fan Proof of Flow Switch
The MUA II Controller can monitor a Fan Proof of Flow Switch con-
tact closure on analog input #7. When this option is used, the Outside
Dewpoint Reset from Space Humidity option is not available as it also
connects to analog input #7. Anytime the fan is running, this contact must
be closed. If the contact does not close or remain closed, no heating or
cooling outputs can activate or remain active. If this option is selected,
the loss of this signal can generate an alarm so that you know there is a
problem that needs to be corrected. There is a built-in fi ve-second fi lter
provided to prevent intermittent contact “bounce” from affecting the
operation. This option is not available.
Remote Occupied Contact
If you have a separate source that will provide a dry contact closure
to indicate the occupied mode, you can monitor this contact closure in
place of a humidity sensor on analog input #3.
Outside Air Temperature Broadcast
If you have several Air Handlers on a jobsite and they are connected
together via the RS-485 communications loop, you can select this op-
tion and confi gure the controller to broadcast Outside Air Temperature
to all controllers on the network, instead of installing a Outside Air
Temperature sensor on every unit. This saves you from having to install
duplicate sensors on every air handler.
Outside Air Humidity Broadcast
If you have several Air Handlers on a jobsite and they are connected
together via the RS-485 communications loop, you can select this option
and confi gure the controller to broadcast Outside Air Humidity to all
controllers on the network, instead of installing a Outside Air Humidity
sensor on every unit. This saves you from having to install duplicate
sensors on every air handler.
Relay Confi guration
Output Relay Confi guration
Relays #2 through #21 can be confi gured for the type of function that
matches the MUA II Controller options. The relays can be confi gured for
any of the following: Heating (aux. Heating) Stages, Cooling (compres-
sor) Stages, Gas Reheat Control for De-Humidifi cation, and External
Heat Enable for control of external heating devices.