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Hydronic Heating Control Derivative Gain (HW.D)
This configuration is the derivative term for the PID which runs in
the HVAC mode LOW HEAT.
Hydronic Heating Control Run Time Rate (HW.TM)
This configuration is the PID run time rate which runs in the
HVAC mode LOW HEAT.
Hydronic Heating Logic
If the HVAC mode is LOW HEAT:
•
The control will command the supply fan on.
•
The control will modulate the hot water coil actuator to the
heating control point (Run Status
The heating control point for hydronic heat is the heating
supply air set point (Setpoints
If the HVAC mode is HIGH HEAT:
•
The control will command the supply fan on.
•
The control will command the hot water coil actuator to
100%.
Hydronic Heating PID Process
If the HVAC mode is LOW HEAT, then the hydronic heating actu-
ator will modulate to the heating control point (Run Status
VIEW
HT.C.P). Control is performed with a generic PID
loop where:
Error = Heating Control Point (HT.C.P) – Leaving Air Tempera-
ture (LAT)
The PID terms are calculated as follows:
P = K * HW.P * error
I = K * HW.I * error + "I" last time through
D = K * HW.D * (error – error last time through)
Where K = HW.TM/60 to normalize the effect of changing the run
time rate.
NOTE: The PID values should be not be modified without ap-
proval from Carrier.
Freeze Status Switch Logic (Inputs
If the freezestat input (FRZ) alarms, indicating that the coil is
freezing, normal heat control is overridden and the following ac-
tions will be taken:
1.
Command the hot water coil actuator to 100%.
2.
Command the economizer damper to 0%.
3.
Command the supply fan on.
Configuring Hydronic Heat to Communicate Via Actuator
Serial Number
Every actuator used in the P Series control system has its own
unique serial number. The rooftop control uses this serial number
to communicate with the actuator. These serial numbers are pro-
grammed at the factory and should not need changing. Should
field replacement of an actuator become necessary, it will be re-
quired to configure the serial numbers of the new actuator. Four
individual numbers make up this serial number and these can be
programmed to match the serial number of the actuator in its Hy-
dronic Heating Actuator Configs group, ACT.C (SN.1, SN.2,
SN.3, SN.4). See Fig. 8.
ACTUATOR SERIAL NUMBER
00850 - 30063 - 084 -083
NOT
SN.1 SN.2 SN.3 NOT
USED
Fig. 8 — Actuator Serial Number Configuration
VIEW
HT.C.P).
SA.HT).
GEN.I
FRZ.S)
SN.1 = 850
SN.2 = 3
SN.3 = 63
SN.4 = 83
SN.4
USED
NOTE: The serial numbers for all actuators can be found inside
the control doors of the unit as well as on the actuator itself. If an
actuator is replaced in the field, it is a good idea to remove the ad-
ditional peel off serial number sticker on the actuator and cover up
the old one inside the control doors.
STAGED GAS HEAT CONTROL (HT.CF = 3 AND HT.ST =
0, 1, OR 2)
As an option, the units with gas heat can be equipped with staged
gas heat controls that will provide from 2 to 9 stages of heat capac-
ity. This is intended for tempering mode and tempering economiz-
er air when in a cooling mode and the dampers are at minimum
vent position. 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, modulating gas, and hydronic
heat will be discussed in its own section. This section will focus on
heat mode control, which ultimately is relevant to tempering, mi-
nus the consideration of the supply air heating control point.
MODULATING GAS HEAT CONTROL (HT.CF = 3 AND
HT.ST = 3, 4, OR 5)
As an option, the units with gas heat can be equipped with modu-
lating gas heat controls that will provide infinite stages of heat ca-
pacity. This is intended for tempering mode and tempering econo-
mizer air when in a cooling mode and the dampers are at mini-
mum vent position. Tempering can also be used during a pre-
occupancy purge to prevent low temperature air from being deliv-
ered to the space. Tempering for staged gas, modulating gas, and
hydronic heat will be discussed 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 con-
trol point.
The staged and modulating gas and SCR electric heat configura-
tions are located at the local display under Configuration
HEAT
SG.CF. See Table 46.
SCR ELECTRIC HEAT CONTROL (HT.CF = 5 AND HT.ST
= 6, 7, OR 8)
As an option, the units with electric heat can be equipped with
modulating SCR electric heater controls that will provide infinite
stages of heat capacity. This is intended for tempering mode and
tempering economizer air when in a cooling mode and the damp-
ers are at minimum vent position. 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, modulat-
ing gas, hydronic and SCR electric heat will be discussed 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.
Staged Heat Type (HT.ST)
This configuration instructs the control as to how many stages and
in what order they are staged. Setting HT.ST = 0, 1, or 2 config-
ures the unit for Staged Gas Heat. See Table 47. Setting HT.ST =
3, 4, or 5 configures the unit for Modulating Gas Heat. See
Table 48. Setting HT.ST = 6, 7, or 8 configures the unit for SCR
Electric Heat.
Max Cap Change per Cycle (CAP.M)
This configuration limits the maximum change in capacity per
PID run time cycle.
66
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