3
Heating Curve
To calculate the correct setting for the
design supply temperature –WWSD temperature
Heating Curve, use the following formula:
WWSD temperature – design outdoor temperature
For example: • design outdoor temperature = 5
°
F (-15
°
C)
• WWSD temperature = 70
°
F (21
°
C)
Heating Curve =
=
= 1.4
• design supply temperature = 160
°
F (71
°
C)
If the system design supply water temperature is unknown, a trial setting can be calculated using these typical supply temperatures:
• Fan coils or convectors …180 to 210
°
F (82 to 99
°
C) • Hydronic radiant floors …100 to 130
°
F (38
°
to 54
°
C).
Warm Weather Shut Down (WWSD)
The WWSD can be adjusted from 35 to 105
°
F (2 to 41
°
C) and its function is covered under the Outdoor Reset Strategy section on page 2.
If the DIP switch is selected for one boiler operation, the pump output will cycle on for 20 seconds every three days during WWSD
.
Minimum Boiler Operating Temperature
This adjustment should be set according to the requirements specified by the boiler
manufacturer. Many boilers require a minimum operating temperature to prevent
corrosion from flue gas condensation. The control raises the supply temperature to the
Minimum when the outdoor temperature drops below the WWSD setting, and holds it
there until the outdoor temperature becomes cold enough to require operation on the
heating curve.
Typical Minimum Boiler Operating Temperatures: • Steel Tube Boilers …140
°
to 180
°
F (60
°
to 82
°
C) • Cast Iron Boilers …130 to 150
°
F (54 to 66
°
C) • Copper Tube Boilers …105 to 150
°
F
(41 to 66
°
C) • Condensing or Electric Boilers …off
Settings
Desired temperature
this example
160
°
F(71
°
C)
T
emperature
W
armer
Cooler
Time
Differential
this example
10
°
F(5
°
C)
165
°
F(74
°
C)
155
°
F(68
°
C)
Te
m
p
e
ra
tu
re
fa
ll
BOILER
OFF ON
Te
m
p
e
ra
tu
re
r
is
e
Heating Curve =
Outdoor air temperature
Supply water temperature
50
(10)
30
(-1)
10
(-12)
-10
°
F
(-23)
°
C
110
(43)
70
(21)
70
(21)
90
(32)
210
(99)
170
(77)
150
(65)
130
(54)
190
(88)
3.6 3.0 2.4 2.0
0.8
0.4
1.0
0.6
90
(32)
50
°
F
(10)
°
C
Heating
Curve
1.2
Minimum Supply
Setting 130
°
F
WWSD
Point
70
°
F
1.6
The control automatically goes back to viewing when the buttons are left alone for 20 seconds
The control automatically goes back to viewing when the buttons are left alone for 20 seconds
When the control is
powered-up, all display
elements are turned on.
After approximately 3
seconds, the control
automatically goes into
operating mode.
POWER ON
PROGRAMMING
Push or to change
minumum boiler staging
delay
Push or to
change Heating Curve
(underscore is decimal point)
When in operating mode,
the Outdoor temperature
will be displayed. Boiler(s)
output is on when number
segment is on. When
number is flashing, delay
on is occuring.
Item
VIEWING
Press and Release the
"Item" button. The
programmed Differential
setting will be displayed.
Item
Press and Release the
"Item" button. The
programmed Warm
Weather Shut Down
setting will be displayed.
Item
Item
Press and Release the
"Item" button. The Target
Supply temperature will be
displayed.
Press and Release the
"Item" button. The
programmed Minimum
supply temperature setting
will be displayed. A fast
flashing pointer indicates
programming is active.
Item
Press and Release the
"Item" button. The
programmed Heating
Curve setting will be
displayed.
Push or to select between
Fahrenheit or Celsius scales
Press and Release the
"Item" button. The
Fahrenheit or Celsius
scale may be selected.
Item
Press and Release the
"Item" button. Only with two
boiler option will the minimum
boiler staging delay be
displayed.
Push or to
change Differential
Push or to
change WWSD setting
Min.
Outdoor
Supply
Target Supply
Curve
WWSD
Differential
Min.
Outdoor
Supply
Target Supply
Curve
WWSD
Differential
Min.
Outdoor
Supply
Target Supply
Curve
WWSD
Differential
Min.
Outdoor
Supply
Target Supply
Curve
WWSD
Differential
Min.
Supply
Outdoor
Target Supply
Curve
WWSD
Differential
Min.
Outdoor
Supply
Target Supply
Curve
WWSD
Differential
Min.
Supply
Outdoor
Target Supply
Curve
WWSD
Differential
Min.
Supply
Outdoor
Target Supply
Curve
WWSD
Differential
Min.
Outdoor
Supply
Target Supply
Curve
WWSD
Differential
Item
F
1
PRGM
F
PRGM
F
Min.
Outdoor
Supply
Target Supply
Curve
WWSD
Differential
When only one boiler is
selected, the Pump output
contact will be on
continuously until WWSD
occurs. A slow flashing
pointer indicates control
action.
F
1
Press and Release the
"Item" button. The Supply
temperature will be
displayed.
Item
Push or to
change Minimum supply
temperature
PRGM
PRGM
PRGM
F
PRGM
The display defaults to
outdoor temperature after
power up, or if the control
has been left alone in
programming longer than
20 seconds.
Item
Min.
Outdoor
Supply
Target Supply
F
1
Curve
WWSD
Differential
Min.
F
1
Curve
WWSD
Differential
Outdoor
Supply
Target Supply
F
1
2
PRGM
F C
1
2
F
= 10
°
F (6
°
C)
Differential and Time Delay
The differential adjustment sets how far the actual supply water temperature may deviate
from the desired temperature before a boiler is turned on or off, and is determined by the
flow rate through the system pump relative to the amount of heat produced. When using
two boilers, boiler # 2 will be staged on when the actual supply temperature drops below
the control's calculated target supply minus the differential setting. Note: Boiler # 2 delay
time must have expired before boiler # 2 is fired. To prevent short boiler cycles, the
control has a minimum time delay of 30 seconds between firing cycles for the first boiler.
When two boiler operation is selected, the minimum delay between stages is adjustable
from 30 seconds to 4 minutes.
In the following example, boiler # 1 will turn on when the actual temperature falls 5
°
F
(3
°
C) below the desired temperature and will turn off when the actual temperature rises
5
°
F (3
°
C) above the desired temperature
.
100,000 Btu/hr
20 US GPM x 500
=
Differential =
Btu/hr of each stage
System US GPM x 500
90
°
F
65
°
F
160
°
F - 70
°
F
70
°
F - 5
°
F