Patterson-Kelley MACH Series Installation & Owner's Manual page 25

MACH® Series Gas-Fired Boiler
Step
1 Outlet water temp
2 Inlet water temp
3 Domestic Hot Water temp *
4 Outdoor air temp *
5 Flue gas temp
6 Boiler outlet setpoint
7 Rate of change outlet temp ° F/second
8 Rate of change inlet temp ° F/second
Rate of change Domestic Hot Water
9 ° F/second
Second Comfort Heat system
A
temperature
* If the sensors for these functions are not installed,
the display will indicate -22.
3.12.1.2 Operating Configurations
The boiler has several different operating
configurations. These are:
•
Internal Setpoint
•
Domestic Priority
•
Outdoor Air Reset
•
Analog Input Setpoint
•
Analog Input Direct Drive
CAUTION!
Do not modify any parameters other than those
specifically mentioned.
Internal Setpoint:
The internal setpoint is set with parameter 4. The
boiler temperature control modulates the boiler to
maintain this internal setpoint. The upper and lower
temperature differentials are used to instruct the boiler
at what temperature to turn on and at what temperature
to turn off.
Item Parameter
Setpoint
Low Temp. Differential
Value
Value Allowable
Range
4 160 68-185
22 10 0-36
High Temp. Differential
Low Temp. Setpoint
The boiler will modulate to try to maintain 160° F. If
the temperature increases above 169° F which is the
setpoint 160° F + High Temp Differential 9°F the
boiler will shut off. Once it shuts off it will not
restart until the temperature drops below 150° F
which is the setpoint – Low Temp Differential. The
Low Temp Set Point will not permit the operator to
adjust the setpoint below 68° F. (See graph below.)
175
170
165
Boiler Temperature
160
155
150
145
0
Domestic Priority:
If an indirect domestic hot water (DHW) tank is
connected, the DHW function of the boiler will
activate when the DHW temperature controller
(supplied by others) closes (Terminal 5 to 8 TB 1,
refer to Section 6.1.1), indicating a call for heat from
the DHW system. The parameters should be set as
follows:
Item
DHW Setpoint
DHW Setpoint Addition
DHW Status
DHW High Temp. Differential
DHW Low Temp. Differential
DHW Options
In the above example, the boiler temperature will be
set to the DHW Setpoint + the DHW Setpoint
Addition (140ºF + 30ºF = 170ºF) when the DHW
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5 68
Internal Setpoint
Boiler Turns Off
Boiler Set Point
Boiler Turns On
10 20 30
Time
Parameter
1
33
2
25
24
35
Installation
0-36
59-140
40
Value
140
30
1
6
6
13