Bosch Appliances GWH 425 PN/HN4GWH 4254, GWH 260 PN/HN2 manual GWH 425 EF Technical Specifications

Applications manual 11

2.7 Bosch GWH 425 EF

Features:

Electronic ignition and built in power vent Thermal efficiency of 82%

Vents with 4" stainless steel or galvanized vent pipe Specifically designed for horizontal vent terminations Modulating gas valve — ensures temperature stability

Model GWH 425 EF N for natural gas (NG) supply Model GWH 425 EF L for liquid propane (LP) supply 15-year warranty

Qualifies for $300 tax credit (LP only)

GWH 425 EF Technical Specifications

Gas input	Natural Gas:		28,000 - 130,000 Btu/h
	LP Gas:		28,000- 125,000 Btu/h
Minimum flow to	0.5 gallons per minute (GPM)
activate
Maximum flow rates	4.6 gpm @ 45°F rise
Thermal Efficiency	NG: 80% LP: 82%
Dimensions	29.75" h x 18.25" w x 8.75" d
Weight	44 lbs.
Modulating gas valve	yes
Ignition	Electronic
GWH 425 EF Installation Specifications
Gas connection		½" Male NPT
Water connections		½" Male NPT
NG gas pressure		Minimum: 7" W.C.
		Maximum: 14" W.C.
LP gas pressure		Minimum: 11" W.C.
		Maximum: 14" W.C.
Electrical supply		120VAC - plugs in
Venting		4" stainless steel (AL29-4C)
		or 26 gauge galvanized
GWH 425 EF Installation Clearances
Top (A)	12"
Front (B)	4"
Back	0"
Sides	4"
Floor (C)	12"

Fig. 1 Venting configurations

Installation guidelines:

Venting:

4" AL29-4C sealed stainless steel or 26 gauge galvanized vent pipe.

Slope horizontal runs up to termination ¼" per foot. Do not combination vent with any other appliance. See manual for vent terminator clearances.

Gas piping:

Heater will not function properly without adequate supply gas pressure.

Any appliance connector should be ¾" minimum diameter

Plumbing:

Install the included pressure relief valve and pipe to suitable drain.

Minimum piping diameter is ½".

Do not solder directly to connections on the bottom of the unit. Use full port ball valves for isolation valves.

Bosch Water Heating Applications manual 11.2007