user manual

11
Heat Controller, Inc. DXM2 UNIT CONTROLS Application, Operation, & Maintenance Manual
will change to the appropriate Heating Stage 3 airfl ow.
With continuing Heating Stage 3 demand, EH2 will turn on
after 10 minutes. EH1 and EH2 are turned off immediately
when the Heating Stage 3 demand is removed, and the
control reverts to Heating Stage 2 Mode. During Heating
Stage 3 Mode, EH2 will be off (or will turn off if already on)
if LT1 is greater than 45°F AND LT2 is greater than 110°F
(LT2 greater than 110°F includes the condition that LT2 is
shorted). This condition will have a 30-second recognition
time.
Emergency Heat - In Emergency Heat Mode, the selected
fan output(s) will be activated at high speed or the
appropriate airfl ow for Emergency Heat, and EH1 is turned
on immediately. With continuing Emergency Heat demand,
EH2 will turn on after 5 minutes. EH1 and EH2 are turned
off immediately when the Emergency Heat demand is
removed. The selected fan output(s) will turn off after the
selected heating blower off delay and the control reverts to
Standby Mode.
Cooling Stage 1 - In Cooling Stage 1 Mode, the selected
fan output(s), Compressor, and RV relays are turned on
immediately. If confi gured as Stage 2 (DIP1.2 = off), then
the compressor and fan will not turn on until there is Stage
2 demand. The Compressor relay is turned off immediately
when the Cooling Stage 1 demand is removed. The
selected Fan output(s) will turn off after the selected
cooling blower off delay, and the control then reverts to
Standby Mode. The RV relay will remain on until there is
a Heating demand. If there is a Master/Slave situation or
a Dual Compressor situation, all Compressor relays and
related functions will track with their associated DIP1.2.
Cooling Stage 2 - In Cooling Stage 2 Mode, the selected
Fan output(s), Compressor, and RV relays remain on. The
Compressor Speed relay is turned on, and multi–stage fan
confi gurations switch to the appropriate operating speed
for Cooling Stage 2 immediately. The Compressor Speed
relay is turned off immediately when the Cooling Stage 2
demand is removed, and multi–speed fan confi gurations
switch to the appropriate operating speed for Cooling
Stage 1 immediately, and the control reverts to Cooling
Stage 1 Mode. If there is a Master/Slave situation or a dual
compressor situation, all compressor relays and related
functions will track with their associated DIP1.2.
Night Low Limit (NLL) Staged Heating - In NLL Staged
Heating Mode, the OVR input becomes active and is
recognized as a call for Heating (OVR is an alternate
means of calling for Heating Mode). In NLL Staged Heating
Mode, the control will immediately go into Heating Stage
1 Mode with an additional 30 minutes of NLL demand,
the control will go into Heating Stage 2 Mode. With an
additional 30 minutes of NLL demand, the control will go
into Heating Stage 3 Mode.
Blower Confi gurations – The DXM2 may be confi gured
to operate several different blowers and blower
confi gurations. The confi gurations include:
a) 2 Speed PSC Blower – The default confi guration of the
DXM2 is to operate for a 2 Speed PSC blower, with the
K1 relay operating as a blower enable relay, and the
K2 relay operating as a blower speed relay. With this
confi guration, the blower enable relay is momentarily
de-activated when the blower speed relay is switched.
For low speed blower operation (Constant Fan, Heating
1, Cooling 1, Cooling 2 with Dehumidifi cation), K1
will be active and K2 will be inactive. For high speed
blower operation (High Speed Constant Fan, Heating 2,
Heating 3, Emergency Heat, Cooling 2), K1 and K2 will
be active.
b) ECM Blower – If the DXM2 is confi gured for an ECM
blower, OR an ECM blower is detected, the DXM2
will directly control an ECM blower using selected
or default airfl ows for each operating mode. When
operating an ECM blower, the K1 relay becomes a
loop pump relay active anytime the compressor relay is
active, and the K2 relay becomes a HWG pump relay.
c) Single Speed PSC Blower – If the DXM2 is confi gured
for a single speed PSC blower, the K1 relay will operate
as the blower relay, and the K2 relay becomes a HWG
pump relay.
d) Dual Stage PSC Blower – If the DXM2 is confi gured for
a dual stage PSC blower, the K1 relay will operate as a
blower enable relay, and the K2 relay will operate as a
blower speed relay. The dual stage PSC confi guration
operates very similar to the 2 Speed PSC, except the
blower enable relay is not de-activated when the blower
speed relay is switched.
e) No Blower – If the DXM2 is confi gured for no blower
(TTS and TTP units), the K1 relay will become a loop
pump relay and the K2 relay will become a HWG pump
relay.
ECM Blower Operation – When the DXM2 is confi gured
to operate an ECM Blower, or an ECM Blower is connected
to the DXM2, the ECM blower will be directly controlled by
the DXM2, with advanced operating features including:
a) Airfl ow Settings – The DXM2 allows the target airfl ow
for each operating mode to be selected individually,
within the allowable operating range.
b) Soft Start Ramping – During the fi rst 2 minutes of
blower operation during a heating or cooling demand,
the ECM blower will ramp up to the selected target
DXM2 Controls