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GAS-FIRED BOILER Boiler Manual
PART 11: START-UP PROCEDURES FOR THE INSTALLER (CONTINUED)
Function Default Function
Number Value Description
12 68º F Allows the installer to set the low-
est temperature on the Mod Con
for Central Heating. Range: 32ºF
to 200ºF
13 0 Min. Allows the installer to change the
Central Heating Circulator Post
Purge Time once the thermostat is
satisfied. Range 0 to 10 minutes.
14 30 Min. Allows the installer to set the
Maximum run time for the Indirect
Fired Water Heater and the
Minimum run time for Central
Heating. Range 0 to 60 Minutes
15 0 Bus Addressing Boilers (Cascade
8 Boiler Max.)
Master = Address 0 / Followers =
Address 1 thru 7.
Note: Never address boiler with
number 8 which is not to be used.
Range: 0-8
16 0 Allows the installer to connect up
a 0-10 Volt directly from Building
Management System. To activate,
change value to 2.
Warning: Values 1 and 3 are not to
be programmed into board
Range: 0-3
17 0 Allows the user to control the
function of the 0–10 volt input
0 = Boiler Temperature
1 = Boiler Power
18 1 Step Modulation – Regulates the
burner output in 6 steps in one-
minute intervals. This reduces
short cycling.
1 = on
0 = off
19 180° Indirect boiler set point (flow)
Temperature default = 119° to 180°
20 3 Low water cut-off. Do not change
0= none
1=water pressure switch
2=flow switch
3=low water cutoff (MODCON
default)
Function Default Function
Number Value Description
21 0 Allows the installer to set the con-
trol to display |FOU| error. If out-
door sensor is open or shorted
|FOU| error does not prevent boil-
er from running.
0 = No |FOU| displayed.
1 = |FOU| displayed if outdor sen-
sor shorted or open.
22 100% Maximum boiler output percent-
age. Default = 100%. This param-
eter can be adjusted to lower the
maximum boiler output if neces-
sary. Example MODCON500 boil-
er setting at 80% boiler will go to
400000 BTU/hr max rather than
500000 BTU/hr. Range 50–100%
23 0 Cascade configuration default 0.
Change this to 1 if the boiler is a
cascade master
24 24 Power on hours for cascade prior-
ity changeover. This parameter is
used to set how many power on
hours will go by before the priori-
ty boiler will be rotated in the cas-
cade system
25 0 Not applicable, must be at 0
26 -- Only used on Master Boiler in a
multiple boiler installation to pro-
vide system pump activation at a
user defined temperature. Adjus -
tment to the default setting can be
made by pressing the {S/2+} key to
increase temperature
Activation point. Range -40°F to
104°F
* Central Heating Curve Function
The central heating demand is detected when the
room thermostat closes. When an outside sensor
is also connected, the supply temperature will
depend on the factory default central heating
curve which is sufficient for most applications.
To set your own custom heat curve you will
have to set the following parameters. Use graph
in Fig. 11-1 and 11-2 to assist you in the design
of the curve.
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