Specifications
43
Table 48 — Heat/Cool Set Point Offsets
Demand Level Low Heat on Offset (
L.H.ON) —Thisisthe
heating set point offset below the heating set point at which
point Low Heat starts.
Demand Level High Heat on Offset (
H.H.ON) —Thisisthe
heating set point offset below [the heating set point minus
L.H.ON] at which point high heat starts.
Demand Level Low Heat Off Offset (
L.H.OF) —Thisisthe
heating set point offset above [the heating set point minus
L.H.ON] at which point the Low Heat mode ends.
See Fig. 7 for an example of offsets.
To enter into a LOW HEAT mode, if the controlling temper-
ature 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 tem-
perature falls below [the heating set point minus L.H.ON mi-
nus H.H.ON], then HVAC mode = HIGH HEAT.
To get out of a LOW HEAT mode, the controlling tempera-
ture 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 tempera-
ture 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 control types (C.TYP=1
and 2) in the occupied period. This technique 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 relevant for the space sensor
machine control types (C.TYP = 5 and 6) because they 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 Demand Level” section for
more details.
HEAT MODE DIAGNOSTIC HELP — To quickly deter-
mine 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 49 at the local display under Run
Status
→
TRIP.
Table 49 — Mode Trip Helper Table
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.
HT.CF
=1,2(Two-Stage Gas and Electric Heat Control)
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 indoor fan input
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)*
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 indoor fan input
controls the supply fan request
• The control will turn on Heat Relay 1 (HS1)
• 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 supply
airstream sufficient to heat the space.
ITEM EXPANSION RANGE UNITS CCN POINT DEFAULT
D.LV.T
COOL/HEAT SETPT. OFFSETS
L.H.ON
Dmd Level Lo Heat On -1 - 2 ^F DMDLHON 1.5
H.H.ON
Dmd Level(+) Hi Heat On 0.5 - 2.0 ^F DMDHHON 0.5
L.H.OF
Dmd Level(-) Lo Heat Off 0.5 - 2 ^FDMDLHOFF1
L.C.ON
Dmd Level Lo Cool On -1 - 2 ^F DMDLCON 1.5
H.C.ON
Dmd Level(+) Hi Cool On 0.5 - 2 ^F DMDHCON 0.5
L.C.OF
Dmd Level(-) Lo Cool Off 0.5 - 2 ^FDMDLCOFF1
C.T.LV
Cool Trend Demand Level 0.1 - 5 ^F CTRENDLV 0.1
H.T.LV
Heat Trend Demand Level 0.1 - 5 ^F HTRENDLV 0.1
C.T.TM
Cool Trend Time 30 - 600 sec CTRENDTM 120
H.T.TM
Heat Trend Time 30 - 600 sec HTRENDTM 120
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
H.H.ON
L.H.OF
L.H.OF/2
L.H.ON
the "Heating Setpoint"
Fig. 7 — Heating Offsets