62
Demand Level Low Heat Off Offset (L.H.OF)
This is the heating set point offset above [the heating set point
minus
L.H.ON
] at which point the Low Heat mode ends.
To enter into a LOW HEAT mode, if the controlling tempera-
ture falls below [the heating set point minus
L.H.ON
], then
HVAC mode = LOW HEAT.
To enter into a HIGH HEAT mode, if the controlling tempera-
ture falls below [the heating set point minus
L.H.ON
minus
H.H.ON
], then HVAC mode = HIGH HEAT.
To get out of a LOW HEAT mode, the controlling temperature
must rise above [the heating set point minus
L.H.ON
plus
L.H.OF
].
To get out of a HIGH HEAT mode, the controlling temperature
must rise above [the heating set point minus
L.H.ON
plus
L.H.OF
/2].
The Run Status table in the local display allows the user to see
the exact trip points for both the heating and cooling modes
without doing the calculations.
Heat Trend Demand Level (H.T.LV)
This is the change in demand that must be seen within the time
period specified by
H.T.TM
in order to hold off a HIGH HEAT
mode regardless of demand. This is not applicable to VAV con-
trol types (
C.TYP
=1 and 2) in the occupied period. This tech-
nique has been referred to as “Comfort Trending.” As long as a
LOW HEAT mode is making progress in warming the space,
the control will hold off on a HIGH HEAT mode. This is rele-
vant for the space sensor machine control types (
C.TYP
= 4)
because the unit may transition into the occupied mode and see
an immediate and large heating demand when the set points
change.
Heat Trend Time (H.T.TM)
This is the time period upon which the heat trend demand level
(
H.T.LV
) operates and may work to hold off staging or a HIGH
HEAT mode. This is not applicable to VAV control types
(
C.TYP
=1 and 2) in the occupied period. See “Heat Trend De-
mand Level” section for more details.
HEAT MODE DIAGNOSTIC HELP
To quickly determine the current trip points for the low and
high heat modes, there is a menu in the local display which lets
the user quickly view the state of the system. This menu also
contains the cool trip points as well. See Table 42 at the local
display under
Run
Status
TRIP
.
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.
Table 42 — Mode Trip Helper 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 and IFO (IGC fan
output) 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 sup-
ply airstream sufficient to heat the space.
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 and IFO output con-
trols the supply fan request
• The control will turn on Heat Relay 1 (
HS1
)
• The control will turn on Heat Relay 2 (
HS2
)
HYDRONIC HEATING CONTROL (
HT.CF
= 4
)
Hydronic heating in P Series units refers to a hot water coil
controlled by an actuator. This actuator is a communicating ac-
tuator and may be field supplied. When
Configuration
HEAT
HT.CF
=4, there is a thermistor array called
Tempera-
tures
AIR.T
CCT
that is connected to the RXB, that serves
as the evaporator discharge temperature (EDT). The leaving-
air temperature (LAT) is assigned the thermistor that is normal-
ly assigned to EDT and is located at the supply fan housing
(
Temperatures
AIR.T
SAT
).
The configurations for hydronic heating are located at the local
displays under
Configuration
HEAT
HH.CF
. See Table 43.
Table 43 — Hydronic Heat Configuration
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
DEFAULT
HH.CF
HYDRONIC HEAT CONFIGS
HW.P
Hydronic Ctl.Prop. Gain
0 to 1.5
HW_PGAIN
1
HW.I
Hydronic Ctl.Integ. Gain
0 to 1.5
HW_IGAIN
1
HW.D
Hydronic Ctl.Derv. Gain
0 to 1.5
HW_DGAIN
1
HW.TM
Hydronic PID Rate Config
15 to 300
sec
HOTWPIDR
90
ACT.C
HYDR.HEAT ACTUATOR CFGS.
SN.1
Hydronic Ht.Serial Num.1
0 to 9999
HTCL_SN1
0
SN.2
Hydronic Ht.Serial Num.2
0 to 6
HTCL_SN2
0
SN.3
Hydronic Ht.Serial Num.3
0 to 9999
HTCL_SN3
0
SN.4
Hydronic Ht.Serial Num.4
0 to 254
HTCL_SN4
0
C.A.LM
Hydr.Ht.Ctl.Ang.Lo Limit
0 to 90
HTCLCALM
85
Summary of Contents for Weathermaster 48P2030-100
Page 130: ...130 Fig 19 Typical Power Schematic Sizes 040 075 Shown ...
Page 131: ...131 Fig 20 Main Base Board Input Output Connections ...
Page 132: ...132 Fig 21 RXB EXB CEM SCB Input Output Connections ...
Page 133: ...133 Fig 22 Typical Gas Heat Unit Control Wiring 48P030 100 Units Shown ...
Page 134: ...134 Fig 23 Typical Electric Heat Wiring 50P030 100 Units Shown ...
Page 135: ...135 Fig 24 Typical Power Wiring 115 V ...
Page 136: ...136 Fig 25 Typical Gas Heat Section Size 030 050 Units Shown ...
Page 138: ...138 Fig 27 Component Arrangement Size 030 035 Units ...
Page 139: ...139 Fig 28 Component Arrangement Size 040 075 Units ...
Page 140: ...140 Fig 29 Component Arrangement Size 090 100 Units ...
