Kohler 20-3250 kW Natural Gas and LPG Conversion, Fuel System Changeover Kits Dual Fuel, QCON--7

1

2

LPG Liquid Withdrawal Operation

DDisconnect lead 73A from the fuel solenoid valve.

DConnect lead 73B to the fuel solenoid valve (LPG liquid withdrawal).

DConnect lead 65 to lead N5 (ground).

3

Auto Changeover Natural Gas/LPG Vapor Operation

1. Electronic-controlled pressure regulator (EPR)

2. Fuel mixer

3. Fuel solenoid valve

SB-700

DDisconnect lead 65 from N5.

DConnect lead N5 to LFP2 relay common terminal.

DConnect lead 73A to the fuel solenoid valve (natural gas).

DConnect lead 73B to the fuel solenoid valve (LPG vapor).

Eng. Natural LPG LPG Auto

(UL--listed models require 2 fuel solenoid valves)

Figure 3-8 Fuel Regulator and Valve, Typical

3.6.3Natural Gas and LPG Conversion

Most models operate on either natural gas or LPG fuel by performing the fuel conversion procedure. A hang tag on the fuel regulator may provide additional conversion setup information. Fuel conversion may decrease generator set output. Refer to the respective generator set spec sheet for ratings based on fuel selection. Changing fuel does not alter the emissions compliance of the generator set engine. Consult your local generator set distributor/dealer for additional information.

Note: If a gas-fueled model has the fuel type changed (LPG to natural gas or natural gas to LPG), order a new nameplate from an authorized distributor/ dealer with the updated ratings and attach to the generator set.

To change the fuel type, change the electrical connections between the fuel system and the engine ECM. The engine ECM has fuel tables and spark advance curves programmed for both natural gas and LPG. The information shown below, in Figure 3-9, and in Figure 3-10 generally apply to all models and all fuels. Be sure to review the respective wiring diagram for your specific model for possible special applications.

Natural Gas Operation

DDisconnect lead 65 from lead N5.

DDisconnect lead 73B from the fuel solenoid valve.

DConnect lead 73A to the fuel solenoid valve.

LPG Vapor Operation

DDisconnect lead 73A from the fuel solenoid valve.

DConnect lead 73B to the fuel solenoid valve (LPG vapor).

DConnect lead 65 to lead N5 (ground).

ECM	Gas	Vapor	Liquid	Changeover
	QCON--7			QCON--7
	(NG fuel
73A		not used		(NG fuel
	solenoid
				solenoid valve)
	valve)
N5	not used	65	65	LFP2--COM
73B	not used	QCON--10 (LPG fuel solenoid valve)
65	not used	N5	N5	not used
63	LFP1--NC low fuel pressure sensor (if used)
70E2		P6--B (15 amp fuse)

Figure 3-9 Gas Fuel Electrical Connections

3.6.4Fuel System Changeover Kits (Dual Fuel)

Automatic Changeover

A changeover fuel system kit provides automatic changeover from natural gas to LPG vapor. The primary and backup fuels each have a fuel solenoid valve. The primary fuel is natural gas; the backup fuel is LPG vapor. Before starting, both fuel solenoid valves are closed. When the generator set starts, the primary fuel solenoid valve opens. The primary fuel line has a pressure switch in series with a relay connected to the start/run circuit.

When the primary fuel pressure drops below 0.6 kPa (1.4 oz./in.2) or 6.4 cm (2.5 in.) water column , a relay opens the backup fuel solenoid valve and closes the primary fuel solenoid valve. When the primary fuel pressure rises above 0.6 kPa (1.4 oz./in.2) or 6.4 cm (2.5 in.) water column, the generator set uses the primary fuel. Contact an authorized service distributor/dealer for kit availability.

TP-6200 10/12 Section 3 Scheduled Maintenance 143