Patterson-Kelley MACH-05 Internal Setpoint, Domestic Priority, Parameter, Value, Allowable, Range

MACH® Series Gas-Fired Boiler

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	Value	Allowable
			Range
Setpoint	4	160	68-185
Low Temp. Differential	22	10	0-36
High Temp. Differential	23	9	0-36
Low Temp. Setpoint	5	68	59-140

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.)

		Internal Setpoint
175
170			Boiler Turns Off
165	Boiler Temperature
160		Boiler Set Point
155
150	Boiler Turns On
145
0	10	20	30	40
		Time

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:

		Installation
Item	Parameter		Value
DHW Setpoint	1		140
DHW Setpoint Addition	33		30
DHW Status	2		1
DHW High Temp. Differential	25		6
DHW Low Temp. Differential	24		6
DHW Options	35		13

In the above example, the boiler temperature will be set to the DHW Setpoint + the DHW Setpoint Addition (140ºF + 30ºF = 170ºF) when the DHW temperature controller indicates a call for heat from the DHW system. When the DHW system calls for heat, the Central heat pump output (Terminal 10 TB2) de-energizes and the DHW pump output (Terminal 11 TB2) energizes providing 120 VAC power is provided to energize a relay coil for the DHW pump. The DHW status should be set to 1 (DHW system ON).

Page 22