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Table 65 — Heating Configuration
*Some defaults are model number dependent.
Occupied Heating Enable (OC.EN) — This configuration
only applies when the unit’s control type (Configuration
UNIT
C.TYP) is configured for 1 (VAV-RAT) or 2 (VAV-
SPT). If the user wants to have the capability of performing
heating throughout the entire occupied period, then this config-
uration needs to be set to “YES”. Most installations do not re-
quire this capability, and if heating is installed, it is used to heat
the building in the morning. In this case set OC.EN to “NO”.
NOTE: This unit does not support simultaneous heating and
cooling. If significant simultaneous heating and cooling
demand is expected, it may be necessary to provide additional
heating or cooling equipment and a control system to provide
occupants with proper comfort.
MBB Sensor Heat Relocate (
LAT.M) — This option allows
the user additional performance benefit when under CCN
Linkage for the 2-stage electric and gas heating types. As two-
stage heating types do not “modulate” to a supply air set point,
no leaving air thermistor is required and none is provided. The
evaporator discharge thermistor, which is initially installed up-
stream of the heater, can be repositioned downstream and the
control can expect to sense this heat. While the control does not
need this to energize stages of heat, the control can wait for a
sufficient temperature rise before announcing a heating mode
to a CCN linkage system (ComfortID™).
If the sensor is relocated, the user will now have the
capability to view the leaving-air temperature at all times at
Temperatures
AIR.T
CTRL
LAT.
NOTE: If the user does not relocate this sensor for the 2-stage
electric or gas heating types and is under CCN Linkage, then
the control will send a heating mode (if present) uncondition-
ally to the linkage coordinator in the CCN zoning system
regardless of the leaving-air temperature.
Fan-Off Delay, Gas Heat (
G. F O D ) — This configuration is
the delay in seconds, after a gas heat mode has ended
(HT.CF=2,3) that the control will continue to energize the
supply fan.
Fan-Off Delay, Elec Heat (
E.FOD) — This configuration is
the delay in seconds, after an electric heat mode has ended
(HT.CF=1) that the control will continue to energize the
supply fan.
HEAT MODE SELECTION PROCESS — There are two
possible heat modes that the control will call out for heating
control: HVAC Mode = LOW HEAT and HVAC Mode =
HIGH HEAT. These modes will be called out based on control
type (C.TYP).
VAV-RAT (
C.TYP = 1) and VAV-SPT (C.TYP = 2) — There
is no difference in the selection of a heating mode for either
VAV-RAT or VAV-SPT, except that for VAV-SPT, space tem-
perature is used in the unoccupied period to turn on the supply
fan for 10 minutes before checking return-air temperature. The
actual selection of a heat mode, LOW or HIGH for both
control types, will be based upon the controlling return-air
temperature.
With sufficient heating demand, there are still conditions
that will prevent the unit from selecting a heat mode. First, the
unit must be configured for a heat type (Configuration
HEAT
HT.CF not equal to “NONE”). Second, the unit has a
configuration which can enable or disable heating in the
occupied period except for a standard morning warmup cycle
(Configuration
HEAT
OC.EN). See descriptions above in
the Setting Up the System section for more information.
If the unit is allowed to select a heat mode, then the next
step is an evaluation of demand versus set point. At this point,
the logic is the same as for control types SPT Multi-Stage and
SPT-2 Stage, (C.TYP = 5,6) except for the actual temperature
compared against set point. See Temperature Driven Heat
Mode Evaluation section.
Tstat-Multi-Stage (
C.TYP = 3) and Tstat-2 Stage (C.TYP =
4) — There is no difference in the selection of a heat mode be-
tween the control types TSTAT 2-stage or TSTAT multi-stage.
These selections only refer to how cooling will be handled.
With thermostat control the W1 and W2 inputs determine
whether the HVAC Mode is LOW or HIGH HEAT.
W1 = ON, W2 = OFF: HVAC MODE = LOW HEAT*
W2 = ON, W2 = ON: HVAC MODE = HIGH HEAT
*If the heating type is either 2-stage electric or 2-stage gas, the
unit may promote a low heat mode to a high heat mode.
NOTE: If W2 = ON and W1 is OFF, a “HIGH HEAT” HVAC
Mode will be called out but an alert (T422) will be generated.
See Alarms and Alerts section on page 93.
SPT Multi-Stage (
C.TYP = 5) and SPT 2 Stage (C.TYP = 6)
— There is no difference in the selection of a heat mode
between the control types SPT 2-stage or SPT multi-stage.
These selections only refer to how cooling will be handled. So,
for a valid heating type selected (HT.CF not equal to zero) the
unit is free to select a heating mode based on space temperature
(SPT).
If the unit is allowed to select a heat mode, then the next
step is an evaluation of demand versus set point. At this point,
the logic is the same as for control types VAV-RAT and
VAV-SPT (C.TYP = 1,2), except for the actual temperature
compared against set point. See Temperature Driven Heat
Mode Evaluation section on page 52.
ITEM EXPANSION RANGE UNITS CCN POINT DEFAULT
HEAT HEATING CONFIGURATION
HT.CF Heating Control Type 0 - 3 HEATTYPE 0*
HT.SP Heating Supply Air Setpt 80 - 120 dF SASPHEAT 85
OC.EN Occupied Heating Enabled Yes/No HTOCCENA No
LAT.M MBB Sensor Heat Relocate Yes/No HTLATMON No
G.FOD Fan Off Delay, Gas Heat 45 - 600 sec GAS_FOD 45
E.FOD Fan Off Delay, Elec Heat 10 - 600 sec ELEC_FOD 30
SG.CF STAGED GAS CONFIGS
HT.ST Staged Gas Heat Type 0 - 4 HTSTGTYP 0*
CAP.M Max Cap Change per Cycle 5 - 45 HTCAPMAX 45*
M.R.DB S.Gas DB min.dF/PID Rate 0 - 5 HT_MR_DB 0.5
S.G.DB St.Gas Temp. Dead Band 0 - 5 ^F HT_SG_DB 2
RISE Heat Rise dF/sec Clamp 0.05 - 0.2 HTSGRISE 0.06
LAT.L LAT Limit Config 0 - 20 ^F HTLATLIM 10
LIM.M Limit Switch Monitoring? Yes/No HTLIMMON Yes
SW.H.T Limit Switch High Temp 110 - 180 dF HT_LIMHI 170*
SW.L.T Limit Switch Low Temp 100 - 170 dF HT_LIMLO 160*
HT.P Heat Control Prop. Gain 0 - 1.5 HT_PGAIN 1
HT.D Heat Control Derv. Gain 0 - 1.5 HT_DGAIN 1
HT.TM Heat PID Rate Config 60 - 300 sec HTSGPIDR 90