Table of Contents
Advertisement
Section B: Mixing Reset
Section B1
General
Mixing Operation
Section B1: General Mixing Operation
MIXING DEMAND
A mixing demand is generated by applying a voltage between 24 and 230 V (ac)
across the Mix Demand terminals (1 and 2). Once voltage is applied, the Mix Demand
pointer is displayed in the LCD. If the control is not in WWSD, the control closed the
Mix Pmp contact. The Mixing Pump segment is displayed in the LCD. The control
calculates a MIX TRG supply temperature based on the outdoor air temperature and
settings. If required, the control operates the boiler in order to provide heat to the
mixing device.
OUTDOOR DESIGN (OUT DSGN)
The OUT DSGN is the outdoor air temperature that is typically the coldest temperature of the year where the building is located.
This temperature is used when doing heat loss calculations for the building.
MIX DESIGN (MIX DSGN)
The MIX DSGN temperature is the supply water temperature required to heat the mixing zones when the outdoor air is as cold
as the Outdoor Design temperature.
MIXING MAXIMUM (MIX MAX)
The MIX MAX sets the highest water temperature that the control is allowed to calculate as the MIX TRG temperature. If the
control does target the MIX MAX setting, and the MIX SUP temperature is within 5°F (3°C) of the MIX MAX, the Maximum
pointer is displayed in the LCD while either the MIX TRG temperature or the MIX SUP temperature is being viewed.
WARM WEATHER SHUT DOWN (WWSD) Occ & UnOcc
When the outdoor air temperature rises above the WWSD setting, the control turns on the WWSD pointer in the display. When
the control is in Warm Weather Shut Down, the Mix Demand pointer is displayed if there is a demand. However, the control
does not operate the heating system to satisfy this demand.
MIXING INDOOR (MIX INDR)
The MIX INDR is the room temperature used in the original heat loss
calculations for the building. This setting establishes the beginning
of the Characterized Heating Curve for the mixing zones.
MIXING MINIMUM (MIX MIN)
The MIX MIN is the lowest temperature that the control is allowed
to use as a MIX TRG temperature. During mild conditions, if the
control calculates a MIX TRG temperature that is below the MIX
MIN setting, the MIX TRG temperature is adjusted to match the MIX
MIN setting. During this condition, the Minimum pointer turns on
in the LCD when either the MIX TRG temperature or the MIX SUP
temperature is being viewed.
If either an Indoor Sensor or a Room Temperature Unit (RTU) is used
and the control is operating at the MIX MIN temperature, the Mixing
Pump is cycled using Pulse Width Modulation (PWM) with a 15
minute cycle length. By cycling the Mixing Pump and controlling the
fl ow of supply water, the control provides an average supply water
temperature to the mixing system. This average temperature is equal
to the original MIX TRG. This minimizes overheating of the zone
while the control is operating at the MIX MIN temperature.
ROOM OCC & UNOCC (ROOM)
The ROOM setting is the desired room temperature for the mixing zones and it provides a parallel shift of the Characterized
Heating Curve. The room temperature desired by the occupants is often different from the design indoor temperature (MIX
INDR). If the room temperature is not correct, adjusting the ROOM setting increases or decreases the amount of heat available
to the building. If the Setback / None DIP switch is set to Setback, a ROOM setting must be made for both the Occupied and
UnOccupied modes.
Section B2
Alternate Mixing
Demand
Mixing Characterized
Mixing Characterized
Heating Curve
Heating Curve
MIX MIN
MIX INDR
80
60
(27)
(16)
5 of 32
24 to 230 V (ac)
N
L
MIX MAX
MIX DSGN
OUT DSGN
WWSD Occ
WWSD UnOcc
MIX ROOM Occ
MIX ROOM UnOcc
40
20
0
(5)
(-7)
(-18)
Outdoor Air Temperature
© 2003
190
(88)
170
(77)
150
(66)
130
(54)
110
(43)
90
(32)
70
(21)
50˚F
(10˚C)
-20
(-29)
D 362e - 06/03
Advertisement
Table of Contents
