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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.FOD
) — 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
Summary of Contents for WEATHERMAKER 48/50AJ
Page 103: ...103 Fig 15 Typical Main Control Box Wiring Schematic 48 50AJ AK AW AY Units cont a48 8355 ...
Page 104: ...104 Fig 16 Typical Main Control Box Wiring Schematic 48 50A2 A3 A4 A5 Units a48 8355 ...
Page 105: ...105 TO NEXT PAGE Fig 17 Typical Auxiliary Control Box Wiring Schematic A48 7294 ...
Page 106: ...106 Fig 17 Typical Auxiliary Control Box Wiring Schematic cont a48 8356 ...
Page 107: ...107 Fig 18 Typical 2 Stage Gas Heat Wiring Schematic Size 051 and 060 Units Shown a48 8357 ...
Page 113: ...113 Fig 22 Typical Power Schematic 48 50A2 A3 A4 A5060 Unit Shown ...
Page 114: ...114 SW1 SW2 OR DEHUMIDIFY SWITCH Fig 23 Typical Controls Option Wiring Schematic a48 8361 ...
Page 115: ...115 Fig 24 Typical Small Chassis Component Location Size 020 035 Units a48 8362 ...
Page 116: ...116 Fig 25 Typical Large Chassis Component Locations Size 036 060 Units A48 7302 ...
Page 169: ...169 APPENDIX C VFD INFORMATION cont Fig F Internal Enclosure Fan Replacement A48 7716 ...