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SSPT reading is available and < (OHSP + STO).
SIf it is unoccupied and the SPT < (UHSP --Unoccupied
HeatingDeadba nd). The indoor fan will be turn on by the
stagingalgorithm.
When all of the above conditions are met, the SHSR is
calculatedand up to 3 stages of heat will turned on and off
to satisfy to maintain the SAT = SHSR. If any of the
above conditions are not met, the SHSR is set to its
minimum value of 35_F.
The Staged Heat Submaster Reference (SHSR) is
calculated as follows:
SHSR = Heating PID function on (error) where error =
(OHSP+ STO) -- Space Temperature
The Maximum SHSR is determined by the SATHI
configuration. If the supply--air temperature exceeds the
SATHIconfigurat ion value, then the heat stages will turn
off. Heat staging will resume after a delay to allow the
supply--airtemperature to drop below the SATHI value.
The maximum number of stages available is dependent on
the type of heat and the number of stages programmed in
the CONFIG and SERVICEconfiguration tables. Staging
will occur as follows for gas electric units, Carrier heat
pumps with a defrost board, or cooling units with ele ctric
heat:
For Heating PID STAGES = 2
HEATSTAGES = 1 (50% capacity) -- energize HS1.
HEATSTAGES = 2 (100% capacity) -- energize HS2.
For Heating PID STAGES = 3 and AUXOUT = HS3
HEATSTAGES = 1 (33%capacity if) -- energizeHS1
HEATSTAGES = 2 (66% ca pacity) --energiz e HS2
HEATSTAGES = 3 (100% capacity) -- energize HS3
Staging will occur as follows For heat pump units with
AUXOUT configured as reversing valve :
For Heating PID STAGES = 2 and AUXOUT = Reversing
Valve Heat (the H3_EX_RV output will stay energized
until there is a cool demand) HEAT STAGES= 1 (50%
capacity) shallenergize CMP1, CMP2, RVS.
HEAT STAGES= 2 (100% capacity) shall energize HS1
and HS2.
Heating PID STAGES = 3 and AUXOUT = Reversing
Valve Heat (the H3_EX_RV output will stay energized
until there is a cool demand)
HEAT STAGES = 1 (33% capacity if) shall energize
CMP1, CMP2, RVS
HEATSTAGES = 2 (66% capacity)shall energize HS1
HEATSTAGES = 3 (100% capacity) shall energize HS2
If AUXOUT is configured for Re versing Valve Cool, then
the H3_EX_RVcontact will be deenergized when there is
a demand for heating. The heat stages will be cycledto
temper the SATso that it will be between the SPT and the
SPT + 10_F (SPT < SAT< (SPT + 10_F)) if :
Sthe numberof heat stages calculated is zero
Sthe OAT< 55_F
San IAQsensor is installed
Sthe IAQMinimum Damper Position > minimum damper
position
Sand the SAT< SPT --10_F.
There is alsoa SAT tempering routinethat will act as SAT
low limit safety to prevent the SATfrom becoming too
cold should the economizer fail to close. One stage of
heating will be energizedif it is not in the Cooling or Free
Cooling mode and the OATi sbe low 55_Fand the SAT is
below 40_F. It will deenergize when the SAT > (SPT +
10_F).
Indoor Air Quality — If the optional indoor air quality
(IAQI) sensoris installed, the PremierLink controller will
maintain indoor air quality within the space at the user
configured differential setpo int (IAQD) in the CONFIG
configuration table. The setpoint is the difference between
the IAQI and an optional outdoor air quality sensor
(OAQ). If the OAQ is not present then a fixed val ue of
400 ppm is used. The actual space IAQ setpoint (IAQS) is
calculated as follows:
IAQS = IAQD + OAQ (OAQ = 400 ppm if not present )
As air quality within the space changes, the minimum
position of the economizer damper will be changed also
thus allowing more or less outdoor air into the space
depending on the relationship of the IAQI to the IAQS.
The IAQ algorithm runs every 30 seconds and calculates
IAQ minimum position value using a PID loop on the
IAQI deviation from the IAQS. The IAQ minimum
position is then compared against the user configured
minimum position (MDP)and the greatest value becomes
the final minimum damper position (IQMP). If the
calculated IAQ minimum positionis greater than the IAQ
maximum damper position (IAQMAXP) decision in the
SERVICE configuration table, then it will be clamped to
IAQMAXP value.
If IAQ is configured for low priority, the positioning of
the economizer damper can be overridden by comfort
requirements. If the SPT > OCSP + 2.5 or the SPT <
OHSP -- 2.5 then IAQ minimum position becomes 0 and
the IQMP = MDP.The IAQ mode will resume when the
SPT ≤OCSP + 1.0 and SPT ≥OHSP --1.0.
If IAQ is configured for high priority and the OAT< 55_F
and the SAT< (SPT --10 _F),the algorithm will enable the
heat stages to maintain the SATbetween the SPT and the
SPT + 10_F.
IAQPre --OccupancyPurge — This function is designed to
purge the space of airborne contaminants that may have
accumulated 2 hours prior to the beginning of the next
occupied period. The maximum damperposition that will
be used is temperature compensated for cold whether
conditions and can be pre--empted by Temperature
Compensated Start function. For pre--occupancy to occur,
the followingconditions must be met:
SIAQ Pre--Occupancy Purge option is enabled in the
CONFIGconfigura tion table
SUnitis in the unoccupied state
SCurrentTime is valid
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