Wayne P250 - Dip Switches; Modulating Valve

64659-001 REV. A 07/06/18
17
Dip Switches
Note: When power is first applied to the iHEAT control system, a 30 second delay will occur before the
system will initiate an attempt to light the burner. No gas will flow during this wait time.
The dip switches at the bottom right corner of the iHEAT board allow changes to the board’s
configuration to be made in the field without reprograming, including switching from natural gas to
propane. To change these settings, turn off power to the board, then set the dip switches according to
the table below.
Switch
Usage
1
OEM specific, manual control enclosure, natural gas
2
OEM specific, manual control enclosure, LP gas
3
OEM specific, automatic control enclosure, natural gas
4
OEM specific, automatic control enclosure, LP gas
5
Universal, natural gas
6
Universal, LP gas
7
Low fire setting used for gas pressure setting
8
Blower motor calibration
Table 6 - Dip Switch Settings
Modulating Valve
Adjusting the modulating valve requires that power be connected to the control board and gas be
connected to the valve. Use a manometer to measure the outlet pressure. Set the high pressure setting
before the low pressure setting. The valve must be mounted with the modulating coil horizontal.
The gas valve controls the pressure of the gas supplied to the burner in order to adjust the burner’s
firing rate. The gas valve will not be able to supply enough gas to achieve the desired firing rate if the gas
line feeding it does not have sufficient pressure. The table below lists the supply pressures necessary to
support different firing rates.
Min. Inlet Pressure required for LP Gas
Orifice
(in.)
Firing Rate
(Btu/hr)
Min. Inlet P
(in. w.c.)
0.147
175,000
11.5
0.136
150,000
11.0
0.1285
140,000
11.0
0.122
120,000
11.0
0.120
110,000
11.0
Min. Inlet Pressure required for Natural Gas
Orifice
(in.)
Firing Rate
(Btu/hr)
Min. Inlet P
(in. w.c.)
0.250
200,000
8.4
0.228
170,000
6.6
0.2055
140,000
6.3
0.193
120,000
5.9
0.186
115,000
5.6
0.182
110,000
5.5
Table 7 - Minimum Inlet Pressure for Natural Gas Burners Table 8 - Minimum Inlet Pressure for LP Burners
The maximum rated inlet pressure to the gas valve is ½ psi (14” w.c.). The valve will be damaged
if higher gas pressure is applied.