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ZONE PANELS
PURGE TIME
Once a call is satisfied the CMM-3 drops the call for the heating or
cooling unit controls, whichever was calling and hold the damper(s) to
the zone(s) that were last calling during the Purge Mode. The Purge
mode is nominally 2 minutes and allows the excess conditioned air in
the plenum to be distributed only to the zone(s) that were last calling.
This eliminates the problem of overshooting the temperature in the
satisfied zones. During the Purge mode the panel can be set to keep
the Fan running during Purge or to let the fan control in the HVAC
unit to control the fan. By using the FIPG (Fan On-In Purge) jumper,
on the top right corner of the control panel, this keeps the fan running
until the Purge mode is over. This mode avoids the fan shutting off
during the Purge mode and coming back on when another zone may
be on constant fan after the Purge Mode is over. This may be more
often used in commercial applications for continuous air circulation
(CAC). In residential applications the fan remaining on, especially in
heating, may be drafty and objectionable. Once all zone thermostats
are satisfied for heating and cooling, the CMM-3 can now accept Fan
calls allowing Continuous Air Circulation (CAC) in those zones where
the thermostat’s Fan Switch is set to ON. These zone dampers will
be OPEN while the dampers to the zones where the Fan Switch is
set to AUTO will be CLOSED. When all zone thermostats are satis-
fied for both Heating and Cooling, and all Fan switches are set to
AUTO position, the HVAC unit will be off and all zone dampers will
return to a normally open position. Once a zone calls for heating,
cooling or fan, the dampers to the calling zones remain open and the
dampers to the zones not calling will close.
HVAC EQUIPMENT SET UP
The CMM-3 is factory set for conventional fossil fuel (oil or gas)
single stage heating and cooling. The panel only needs to be con-
figured when using with a conventional electric furnace or hydro-air
system in order to bring the fan on with a call for heat. By using the
FIH (Fan On-In Heat) jumper, located on the upper right corner of the
board, this allows the Fan to be activated with a call for heat. Once
the heat call is satisfied the fan will shut off as well, as long as the
FIPG jumper is off as well.
CHANGEOVER TIMER
Whenever a call is made for either heating or cooling, the change-
over timer is activated in order to track the amount of time heating
or cooling is on. When an opposite call is made after a first call is
existing the changeover timer calculates the amount of time the unit
has already been supplying the first mode in order to determine how
long it will hold off the opposite call. If an opposite call is made shortly
after the first call, the opposite call may be held off for as much as
20 minutes. If the first call or subsequent calls for the first call mode
has had that mode operating for up to 20 minutes already and an
opposite call comes in after 20 minutes, the changeover timer will im-
mediately recognize the opposite call, shutting off the current mode,
enter the purge mode and automatically switch to the opposite mode.
The longer a call has been running up to 20 minutes, the shorter the
wait time will be for an opposite call. If a call is over 20 minutes and
an opposite call is made the changeover will be immediate following
the purge time. This intelligent changeover timing makes the CMM-3
unique to any other zoning system.
CMM-3
CMM-3K
CHECKOUT
The CMM-3 has unique features that simplify the checkout of the
system and has LED readouts that constantly indicate the system
operation. Once 24 Volt Power is applied to the panel the Green
Power LED will illuminate. This will stay illuminated constantly when
power is applied.
The System LED will provide several different indications based upon
color and if it is flashing.
Heat ON – RED
Heat Overlimit – RED Flashing
Cool ON – GREEN
Cool Overlimit – Green Flashing
FAN ON – AMBER
PURGE – AMBER Flashing
Each zone has its own small Green indicator LED next to each zone
relay. This light is lit when the specific zoning is calling for the mode
shown on the System LED.
WIRING
The CMM-3 is very simple to wire and requires only a minimum
number of connections. The CMM-3 terminal blocks are screw-less
and all wires can easily be pushed into their respective terminal by
de-pressing the button for each point and releasing once the wire is
seated. To remove the wire, just press its button again and remove
the wire.
Zone Dampers – The CMM-3 can power any 24VAC damper, either
2 wire or 3 wire. See specific wiring instructions with the damper and
inside panel cover.
Zone Thermostats – The thermostats wiring will for single stage can
be four or five wire. The fifth wire being the C-Common terminal for
24 Volt powered thermostats. There are 5 terminals on the CMM-3 for
each thermostat, marked Y-G-R-W-C. This wiring is shown on Wiring
Diagram 1 for single stage thermostats.
HVAC Equipment – The HVAC equipment will follow Wiring Diagram
2 for Single Stage Systems.
Transformer – A separate 24 Volt AC, 40VA Transformer is recom-
mended to power the control panel and dampers. Often the trans-
former on the HVAC unit only has enough power for its own controls.
Therefore it is recommended a separate transformer be used to
power this panel and the dampers wired to it.
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