Emergency Heat Control; Multi-Stage Thermostats; Manual And Automatic Changeover Thermostats; Discharge Air Temperature Sensor - Honeywell MiniZone EMM-3U Product Data

• Heat pumps can be controlled by conventional thermostats
because the EMM-3U controls the reversing valve based
on whether the panel is in heat or cool.
— It controls auxiliary heat through the stage timer.
— For heat pump applications, set DIP switch 4 to Off.
• In all cases, when a conventional thermostat is used, the
O/B thermostat type jumper located next to each
thermostat connection must remain disconnected.
Heat Pump Thermostats
Heat pump thermostats that have a single Y terminal for first
stage heat and cool and those with separate Y1 and W1 can
be used with the EMM-3U. Thermostats of either type can be
used on any zone. Set DIP switch 4 to Off for heat pump
control.
HEAT PUMP THERMOSTATS WITH SINGLE Y OUTPUT
Thermostats with a single Y wire for first stage heat and cool
can be connected to the EMM-3U. O/B thermostat type
jumpers must be set correctly:
— If the thermostat uses O for changeover, connect it to
the O/B thermostat terminal on the panel and connect
the O/B jumper on the panel. (There is one jumper for
each zone.)
— If B is used, leave the jumper disconnected.
HEAT PUMP THERMOSTATS WITH SEPARATE Y1 AND W1
TERMINALS
• Heat pump thermostats with separate Y1 and W2 terminals
for first stage can be used to control a heat pump.
• On these installations, it is not necessary to connect O or B
from the thermostat.
• Leave the O/B thermostat type jumper disconnected.

Emergency Heat Control

NOTE: Emergency heat is defined as using an auxiliary heat
source without using the heat pump. When the Em
Heat switch is in the Em Ht position, the heat pump is
locked out and calls for heat are sent to the E equip-
ment terminal.
• A recommended heat pump thermostat (see Table 1) can
also switch the board to the emergency heat mode. When
one or more thermostats is in emergency heat, the board
locks out the heat pump.
• When the same source of heat is used for auxiliary heat
and emergency heat, the W2 and E equipment terminals
are jumpered together. Set DIP switch 12 to the Off
position.
• When a different source of heat is used for Auxiliary Heat
and Emergency Heat, Auxiliary Heat is wired to W2 and
Emergency Heat is wired to E. Set DIP switch 12 to On.
When the EMM3-U is then set to Emergency heat, it first
engages equipment terminal E on a call for heat and the
second stage of emergency heat is then W2.

Multi-Stage Thermostats

Use multi-stage thermostats to control up to two stages of
heat or cool with the Y2 and W2 thermostat terminals on the
panel.
EMM-3U UNIVERSAL ELECTRONIC MINIZONE™ PANEL
Manual and Automatic Changeover
Thermostats
Manual or automatic changeover thermostats can be used.
• The panel determines the call for heat or cool based on
which was called for first.
• Subsequent calls for heat or cool are honored when the
initial call is satisfied, or 20 minutes has elapsed.
Rebooting the Microprocessor
To reset the panel, press and release the Boot button. The
system reboots and enters the Purge mode.

Discharge Air Temperature Sensor

The C7735A1000 Discharge Air Temperature Sensor is a
supply-duct-mounted temperature probe used to control
capacity and prevent high limit or coil icing.
• The sensor attaches to the two DATS terminals on the
panel.
• When a high or low limit is reached, the panel shuts off the
equipment and keeps the fan operating for 2-1/2 minutes.
• After this time, it re-energizes the equipment after the
discharge air temperature recovers by ten degrees.
• When the DATS exceeds the high or low limit, the Heat
(red) or Cool (green) LED flashes.
• Set the temperature to 120°F for heat pump systems or
160°F for fossil fuel. The low limit can be set to 40°F or
48°F.
See Table 4 to configure high and low limit using DIP switches
5 and 6.
IMPORTANT
Be sure the Discharge Air Temperature Sensor
wiring does not run parallel with line voltage wiring
unless more than 12 inches of separation exists or
shielded cable is used.
NOTE: The yellow purge LED flashes in all modes other
than purge when there is a DATS failure, a wiring
problem, or when no DATS is connected to the
panel.
The zone control panel will continue to operate correctly when
the purge LED is flashing but without the high and low limit
protection.
Circuit Breaker Protection
A built-in thermal circuit breaker protects the panel against
shorts in the thermostat and damper wiring:
• When the circuit breaker is tripped, none of the LEDs
illuminate and the yellow rectangular component located
left of the R and C terminals is hot when touched.
• Remove power to the panel for at least five minutes to
allow the breaker to cool and reset.
• To eliminate the short, verify damper and thermostat wiring.
Fan On In Heat
The system blower can be set to come on with a call for heat
as required for hydro-air or electric heat systems:
• Setting DIP switch 7 to Off configures the blower to engage
with a call for heat.
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