50
The controlling temperature is “
TEMP
” and is in the middle
of the table for easy reference. Also, the “HVAC” mode can be
viewed at the bottom of the table.
Two-Stage Gas and Electric Heat Control (
HT.CF=1,2
) —
If the HVAC mode is LOW HEAT:
• If Electric Heat is configured, then the control will
request the supply fan ON
• If Gas Heat is configured, then the IGC indoor fan input
controls the supply fan request
• The control will turn on Heat Relay 1 (
HS1
)
• If Evaporator Discharge Temperature is less than 50 F,
then the control will turn on Heat Relay 2 (
HS2
)*
*The logic for this “low heat” override is that one stage of
heating will not be able to raise the temperature of the supply
airstream sufficient to heat the space.
Table 52 — Mode Trip Helper Table
If the HVAC mode is HIGH HEAT:
• If Electric Heat is configured, then the control will
request the supply fan ON
• If Gas Heat is configured, then the IGC indoor fan input
controls the supply fan request
• The control will turn on Heat Relay 1 (
HS1
)
• The control will turn on Heat Relay 2 (
HS2
)
HT.CF
= 3
(Staged Gas Heating Control) — As an option,
the units with gas heat can be equipped with staged gas
heat controls that will provide from 5 to 11 stages of heat
capacity. This is intended for tempering mode and tempering
economizer air when in a cooling mode and the dampers
are fully closed. Tempering can also be used during a pre-
occupancy purge to prevent low temperature air from being
delivered to the space. Tempering for staged gas will be dis-
cussed in its own section. This section will focus on heat mode
control, which ultimately is relevant to tempering, minus the
consideration of the supply air heating control point.
The staged gas configurations are located at the local
display under
Configuration
HEAT
SG.CF
.
See Table 53.
Staged Gas Heat Type (
HT.ST
) — This configuration sets the
number of stages and the order that are they staged.
Max Cap Change per Cycle (
CAP.M
) — This configuration
limits the maximum change in capacity per PID run time cycle.
S.Gas DB Min.dF/PID Rate (
M.R.DB
) — This configuration
is a deadband minimum temperature per second rate. See
Staged Gas Heating logic below for more details.
St.Gas Temp.Dead Band (
S.G.DB
) — This configuration is a
deadband delta temperature. See Staged Gas Heating Logic
below for more details.
Heat Rise in dF/Sec Clamp (
RISE
) — This configuration
prevents the heat from staging up when the leaving-air tem-
perature is rising too fast.
LAT Limit Config (
LAT.L
) — This configuration senses
when leaving-air temperature is outside a delta temperature
band around setpoint and allows staging to react quicker.
Limit Switch Monitoring? (
LIM.M
) — This configuration
allows the operation of the limit switch monitoring routine.
This should be set to NO as a limit switch temperature sensor is
not used with A Series units.
Limit Switch High Temp (
SW.H.T
) — This configuration is
the temperature limit above which stages of heat will be
removed.
Limit Switch Low Temp (
SW.L.T
) — This configuration is
the temperature limit above which no additional stages of heat
will be allowed.
Heat Control Prop. Gain (
HT.P
) — This configuration is the
proportional term for the PID which runs in the HVAC mode
LOW HEAT.
Heat Control Derv. Gain (
HT.D
) — This configuration is the
derivative term for the PID which runs in the HVAC mode
LOW HEAT.
Heat PID Rate Config (
HT.TM
) — This configuration is the
PID run time rate.
Staged Gas Heating Logic
If the HVAC mode is HIGH HEAT:
• The supply fan for staged gas heating is controlled by the
integrated gas control (IGC) boards and, unless the
supply fan is on for a different reason, it will be con-
trolled by the IGC indoor fan input.
• Command all stages of heat ON.
If the HVAC mode is LOW HEAT:
• The supply fan for staged gas heating is controlled by the
integrated gas control (IGC) boards and, unless the
supply fan is on for a different reason, it will be con-
trolled by the IGC indoor fan input.
• The unit will control stages of heat to the heating control
point (
Run Status
VIEW
HT.C.P
). The heating con-
trol point in a LOW HEAT HVAC mode for staged gas is
the heating supply air setpoint (
Setpoints
SA.HT
).
Table 53 — Staged Gas Configuration
*Some configurations are model number dependent.
ITEM
EXPANSION
UNITS
CCN POINT
TRIP
MODE TRIP HELPER
UN.C.S
Unoccup. Cool Mode Start
dF
UCCLSTRT
UN.C.E
Unoccup. Cool Mode End
dF
UCCL_END
OC.C.S
Occupied Cool Mode Start
dF
OCCLSTRT
OC.C.E
Occupied Cool Mode End
dF
OCCL_END
TEMP
Ctl.Temp RAT,SPT or Zone
dF
CTRLTEMP
OC.H.E
Occupied Heat Mode End
dF
OCHT_END
OC.H.S
Occupied Heat Mode Start
dF
OCHTSTRT
UN.H.E
Unoccup. Heat Mode End
dF
UCHT_END
UN.H.S
Unoccup. Heat Mode Start
dF
UCHTSTRT
HVAC
the current HVAC MODE
String
ITEM
EXPANSION
RANGE
UNITS
CCN POINT
DEFAULTS
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
Содержание Carrier Weathermaker 48A2
Страница 105: ...105 Fig 20 Typical Main Control Box Wiring Schematic 48 50A2 A3 A4 A5 Units...
Страница 106: ...106 Fig 21 Typical Auxiliary Control Box Wiring Schematic...
Страница 107: ...107 Fig 22 Typical 2 Stage Gas Heat Wiring Schematic Size 060 Units Shown a48 8357...
Страница 108: ...108 TO NEXT PAGE Fig 23 Typical Staged Gas Heat Wiring Schematic Size 060 Units Shown A48 7296...
Страница 109: ...109 Fig 23 Typical Staged Gas Heat Wiring Schematic Size 060 Units Shown cont A48 8358...
Страница 110: ...110 Fig 24 Typical Electric Heat Control Schematic 50 Series Size 060 Units Shown a50 8228...
Страница 111: ...111 Fig 25 Typical Power Schematic 48 50A2 A3 A4 A5 060 Unit Shown...
Страница 112: ...112 Fig 26 Typical Low Ambient Controls Option Wiring...
Страница 113: ...113 Fig 27 Typical Small Chassis Component Location Size 020 035 Units...
Страница 114: ...114 Fig 28 Typical Large Chassis Component Locations Size 040 060 Units...
Страница 118: ...118 Fig 30 Economizer Control Board ECB1 and VAV Control Board ECB2 A48 7706...
Страница 142: ...142 A48 3733 Fig 56 Main Burner Removal...
Страница 176: ...176 APPENDIX C VFD INFORMATION cont Fig F Internal Enclosure Fan Replacement A48 7716...