A3091000/A3091250
ProMIX™ 101 Radiant
Heating Reset Control
2
Basic Operation
On installation, five design parameters must be
set:
•
O
utdoor
A
ir
L
ow - the anticipated coldest
outdoor design temperature. The same
figure used to calculate heat loss and
equipment loads.
•
O
utdoor
A
ir
H
igh - The average room
setpoint temperature, for example 65
°
F.
This value will also serve as the warm
weather shutdown. Once outdoor tem-
perature reaches the room setpoint
temperature, the heat loss is zero and the
control is deactivated.
•
P
rimary
L
oop
L
ow (minimum boiler return
water temperature) - Some types of
boilers require a minimum return water
temperature to protect the boiler from
condensing such as cast iron boilers. If
no boiler return protection is required, this
dial should be turned counter-clockwise
to the "Cold Start" setting.
•
S
econdary
L
oop
H
igh (maximum radiant
loop temperature) - the hottest water
temperature required to satisfy the radiant
panel at design conditions or coldest
outdoor temperature. Refer to
OAL
•
S
econdary
L
oop
L
ow (minimum radiant
loop temperature) - the minimum water
temperature required to meet the de-
mands in the beginning and end of the
heating season.
The design temperatures are read from the
potentiometer dial settings when the system is
first started up, and may be displayed and
changed at anytime.
Three sensors are continuously monitored and
displayed: Outdoor Air (
OA
), Primary Loop
(
PL
), and Secondary Loop (
SL
). Also dis-
played is the optimum Secondary Loop Setpoint
(
SLS
), calculated based on the design settings
and the current OA temperature. (The colder it
is outside, the warmer the desired water tem-
perature.)
The
SL
sensor provides feedback for the
control loop. To provide the proper temperature
in the radiant loop, the control positions the
valve using a proportional-integral algorithm. If
the
PL
sensor indicates a possibility of the
return temperature falling below the selected
minimum, the opening of the valve is reversed
to prevent condensation of the flue gases, and
the boiler is turned on (if not already running) to
raise the primary loop temperature.
The heat demand LED light when any of the
heating zones calls for heat. Then the “Heat
Demand” input causes the control to turn on the
secondary circulator and the Circ. LED. The
boiler and its LED are not turned on until the
valve reaches 50% open. When the
SL
tem-
perature is high enough to allow the modulation
valve to close down to 10% open, the boiler
output is turned off. The control will keep the
boiler running for at least five minutes before the
boiler shuts off.
When the
OA
temperature reaches the room
setpoint temperature or warm weather shut-
down setting, the control will close the propor-
tional valve, turn off the circulator and the boiler,
and turn on the warm weather shut down LED.
At anytime during setup or operation, an error
caused by a faulty sensor will be indicated on
the display by the sensor name (
OA
/
PL
/
SL
),
“
Err
”, and whether the sensor is open (
Opn
) or
shorted (
Sht
). The test mode allows the inputs
and outputs to be checked for proper operation.
Temperature Setting Guidelines
OAL:
The outside design temperature should
be set according to the standard design
temperature for the geographic area.
OAH:
The warm weather shutdown tempera-
ture should be set to the average ther-
mostat setpoint temperature. This will
also be the outdoor temperature at
which no heat is desired.
