51
Table 49 — Heating Configuration
*Some defaults are model number dependent.
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 tempera-
ture is used in the unoccupied period to turn on the supply fan for
10 minutes before checking return-air temperature. The actual se-
lection 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 con-
figuration which can enable or disable heating in the occupied
period except for a standard morning warm-up cycle (Configu-
ration
HEAT
OC.EN). (Morning warm up is a Linkage
function.) See descriptions in the Setting Up the System sec-
tion for more information.
If the unit is allowed to select a heat mode, then the next step is an
evaluation of demand versus setpoint. 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
setpoint. See Temperature Driven Heat Mode Evaluation section.
Tstat-Multi-Stage (C.TYP=3) and Tstat-Multi-Stage2 (C.TYP=4)
There is no difference in the selection of a heat mode between
the control types TSTAT multi-stage2 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.
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 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 on
page 101.
SPT Multi-Stage (C.TYP = 5) and SPT Multi-Stage2
(C.TYP = 6)
There is no difference in the selection of a heat mode between the
control types SPT Multi-Stage2 or SPT multi-stage. 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 setpoint. 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 setpoint. See
Temperature Driven Heat Mode Evaluation section.
TEMPERATURE DRIVEN HEAT MODE EVALUATION
This section discusses the control method for selecting a heating
mode based on temperature. Regardless of whether the unit is con-
figured for return air or space temperature, the logic is exactly the
same. For the rest of this discussion, the temperature in question
will be referred to as the “controlling temperature.”
First, the occupied and unoccupied heating setpoints under Set-
points must be configured.
Then, the heat/cool setpoint offsets under Configuration
D.LV.T should be set. See Table 50.
Related operating modes are under Operating Modes
MODE
.
The first thing the control determines is whether the unit is in
the occupied mode (OCC) or in the temperature compensated
start mode (T.C.ST). If the unit is occupied or in temperature
compensated start mode, the occupied heating setpoint
(OHSP) is used. In all other cases, the unoccupied heating set-
point (UHSP) is used.
The control will call out a low or high heat mode by comparing
the controlling temperature to the heating setpoint and the heating
setpoint offset. The setpoint offsets are used as additional help in
customizing and tweaking comfort into the building space.
Demand Level Low Heat on Offset (L.H.ON)
This is the heating setpoint offset below the heating setpoint at
which point Low Heat starts.
ITEM EXPANSION RANGE UNITS CCN POINT DEFAULT
HEAT HEATING CONFIGURATION
HT.CF Heating Control Type 0 to 3 HEATTYPE 0*
HT.SP Heating Supply Air Setpt 80 to 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 to 600 sec GAS_FOD 45
E.FOD Fan Off Delay, Elec Heat 10 to 600 sec ELEC_FOD 30
SG.CF STAGED GAS CONFIGS
HT.ST Staged Gas Heat Type 0 to 4 HTSTGTYP 0*
CAP.M Max Cap Change per Cycle 5 to 45 HTCAPMAX 45*
M.R.DB S.Gas DB min.dF/PID Rate 0 to 5 HT_MR_DB 0.5
S.G.DB St.Gas Temp. Dead Band 0 to 5 ^F HT_SG_DB 2
RISE Heat Rise dF/sec Clamp 0.05 to 0.2 HTSGRISE 0.06
LAT.L LAT Limit Config 0 to 20 ^F HTLATLIM 10
LIM.M Limit Switch Monitoring? Yes/No HTLIMMON Yes
SW.H.T Limit Switch High Temp 110 to 180 dF HT_LIMHI 170*
SW.L.T Limit Switch Low Temp 100 to 170 dF HT_LIMLO 160*
HT.P Heat Control Prop. Gain 0 to 1.5 HT_PGAIN 1
HT.D Heat Control Derv. Gain 0 to 1.5 HT_DGAIN 1
HT.TM Heat PID Rate Config 60 to 300 sec HTSGPIDR 90
ITEM EXPANSION RANGE UNITS
CCN
POINT
DEFAULT
OHSP Occupied Heat Setpoint 55 to 80 dF OHSP 68
UHSP
Unoccupied Heat Set-
point
40 to 80 dF UHSP 55
ITEM EXPANSION RANGE CCN POINT
MODE MODES CONTROLLING UNIT
OCC Currently Occupied ON/OFF MODEOCCP
T.C.ST Temp.Compensated Start ON/OFF MODETCST
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