Carrier 50PG20-28 Controls, Start-Up, Operation, Service And Troubleshooting Instructions page 44

The control uses rvvomethods to add a stage of heating. The
first method will add a stage of heating when the
Heating Demand (Operating Modes-+HEAT---aqPT-+
DMD.H) plus the change in heat demand (Operating
Modes -+HEAT_SPT-+TRD.H) times the Heat Thermal Lag
Factor (Operating Modes-+HEAT---)_7PT-+H.LAG) is greater
than the SPT Heat Demand (+) Level (Operating Modes-+
HEAT---_qPT -+HT.. P D ).
DMD.H + TRD.H * H.LAG > HT..PD
The second method will add a stage of heating when Heat
Delnand is greater than the SPT Heat Demand (+) Level plus
0.5° F (DMD.H> HT..PD + 0.5) and the heat demand is chang-
ing at a rate greater than 0.3° F per minute.
The control uses two methods to relnove a stage of heating.
The first method will relnove a stage of heating when the
Heating Demand (Operating Modes-+HEAT---afPT-+
DMD.H) plus the change in heat demand (Operating
Modes -+HEAT---_7PT-+TRD.H) times the Heat Thermal Lag
Factor (Operating Modes-+HEAT---afPT-+H.LAG) is less
than the SPT Heat Demand _) Level (Operating Modes-+
HEAT---a7PT -+HT.ND).
DMD.H + change TRD.H * H.LAG < HT.ND
The second method wilt remove a stage of heating when
Heat Demand is less than the SPY Heat Demand @) Level
minus 0.5 ° F (DMD.H< HL.ND 0.5) and the heat demand is
changing at a rate less than 0.3 ° F per minute.
Confimlrabte delays also apply when adding stages
(Configumtion-+HEAT-+H.IN 0 or removing stages
((bnfiguration-+HEAT-+H.DE O. Heat stage minimuln
on-time ((bnfiguration-+HEAT-+MRT.H) and minilnmn
off-tilne (Configuration -+HEAT+MOT.H) also apply.
SUPPLY-AIR TEMPERATURE (SAT) SENSOR The SAT
Heat Sensing Configuration affects the SAT value displayed.
The confi_ration is accessible via the Scrolling Marquee at
Configuration -+Unit _AT.H.
(bnfiguration-+HEAT---aqAT.H = DSBL When SAT.H =
DSBL, the SAT value on the Scrolling Marquee and CCN
tables will be forced to zero when heat outputs come ON and
for 5 minutes after. The dethult SAT sensor location is at the
thn inlet, upstream of the heat section.
(bnfiguration-+HEAT---aqAT.H = ENBL When SAT.H =
ENBL, the supply-air telnperature measured by the SAT sen-
sor is displayed at the scrolling marquee and the CCN tables
during heating mode. This setting should only be used if the
original SAT sensor is replaced by an accessory SAT sensor
located in the supply duct, downstream of the heat section.
Electric Heat (50PG Units) --
For 50PG units with
factory-installed electric heat, the heat type confim_ration
(bnfiguration-+HEAT-+HT.TY will be factory set to a
value of 2 and the number of heat stages confimaration
(bnfiguration-+HEAT-+?c:HTR wilt be thctory set to match
the installed heater. If electric heat is installed in the field, the
value of HT.TYmust be changed.
Heat will not operate if the outdoor temperature is
greater than the value configmred tbr the heat lockout tempera-
rare, Configm.ation-+HEAT-+HT.LO. Minilnum on-time,
(bnfigumtion-+HEAT.+_lIRT.H, and minimum off-tilne,
(bnfiguration-+HEAT.+3/IOT.H, timeguards apply to both
stages of heating. Factory default values are 2 minutes On and
2 minutes Off
If the indoor fma control is confimared to cycle with the heat-
ing demand ((bnfiguration-+UNIT.+OCFN = No) the
tan will stop after a configured delay (Configuration
-+HEAT-+FOD.E). The factory de_hult value is 30 seconds.
THERMOSTAT CONTROL The first stage of electric
heat (HT.1) will follow the W1 input and the second stage
(HT.2) of heat will follow the W2 input. During auto tan, the
indoor tan wilt follow the HT. 1 output. During cominuous tan,
the indoor tan will follow the G input.
If the user has selected Adaptive (see Cooling section) tbr
thermostat mode, the algorithln will follow the configurable
delays for adding and relnoving stages. When adding addition-
al heat stages, the delay is measured from when the last stage
was added (Configurntion-+HEAT-+H.IN O. Wheal relnov-
ing stages, the delay is measured from when the last stage was
removed ((bnfiguration-+HEAT-+H.DEO. There_bre, if
W1 and W2 turn on silnultaneously, the second stage wilt turn
on after a H.INC delay.
NOTE: If the 1node is not Adaptive, then there are no delays
tbr adding and removing stages.
SPACE SENSOR CONTROL During Space Sensor con-
trol, the electronic conuol uses in_bnnation froln the space
sensor to determine the nmnber of heat stages. Once the nmn-
ber of stages needed tbr heating is determined, either HT.1 or
HT. 1 and HT.2 outputs will be turned on. See Space Sensor
Control section for gas heat units for more information.
NOTE: The jumper wire in the installer's packer must be con-
nected between R and W1 when using a T-55, T-56, or T-58
device. See Major System Components section.
SUPPLY-MR TEMPERATUP, E (SAT) SENSOR The SAT
Heat Sensing Confimlration affects the SAT value displayed.
SAT Heat Sensing (SAT.H) Configuration is accessible via the
Scrolling Marquee at Configumtion-+Unit---_AT.H.
Configuration -+HEAT---_qAT.H = DSBL When SAT.H =
DSBL, the SAT value on the Scrolling Marquee and CCN
tables wilt be forced to zero when heat outputs come ON and
for 5 lninutes after. The default SAT sensor location is at the
tan inlet, upstream of the heat section.
Configuration -+HEAT---_qAT.H = ENBL When SAT.H =
ENBL, the supply-air temperature measured by the SAT sen-
sor is displayed at the scrolling marquee and the CCN tables
during heating mode. This setting should only be used if the
original SAT sensor is replaced by an accessory SAT sensor
located in the supply duct, downstream of the heat section.
Economizer--If
an economizer is installed, then
Econolnizer Installed configuration ((bnfiguration-+
U?ffT-+EC.E?€) should be set to YES. The economizer is
controlled by the economizer output simaal (Outputs'-+
E(DN-+ECCP) on the ECB control. If the indoor tan is offor
the building is unoccupied, the economizer position is zero. If
in Occupied mode and the unit is heating or cooling and the
economizer cannot provide flee cooling, the econolnizer
position is the confimlred economizer minilnum position
(Configuration-+E(DN-+EC.MN) or the position specified
by the IAQ algorithin. If in Unoccupied lnode, the position is
0% open.
The economizer will be allowed to help with cooling if the
outdoor-air telnperamre (Temperature-+AIR.T_OAT) is less
than the confi_red economizer high temperature lockout
(Setpoints-+EH.LO) and greater than the configured econo-
mizer low temperature lockout (Setpoints-+ELLO). It" an
enthalpy sensor is installed, the outdoor telnperamre must be
below the econolniZer high temperature lockout and the
enthalpy (Inputs'.+GEPC:I-+ENTH) must be LOW. For cool-
ing, the econolnizer position can vary bewveen the con-
figured economizer minilnum position ((bnfigumtion-+
E(DN-+EC.MN) and the economizer maxilnum cooling
position ((bnfigumtion -+E_ON-+ECMX).
THERMOSTAT CONTROL ff the unit is in cooling,
operating under thermostat control, Y1 ON, and the econo-
mizer is available tbr cooling, the economizer wilt control the
supply-air temperature to the low cool set point
(Setpoints-+L(SP). When Y2 = ON, the economizer will con-
trol the supply-air temperature to high cool set point
(Setpoints -+IICSP).
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