1 2 | Applications manual |
|
|
2.8 Bosch GWH 425 HN
Features:
Endless hot water for one major application at a time Venting: 5" double wall
Modulating gas valve — constant temperature at varying flow rates Model GWH 425 HN N for natural gas (NG) supply
Model GWH 425 HN L for liquid propane (LP) supply
Qualifies for $300 tax credit
GWH 425 HN Technical Specifications
Gas input | Natural Gas: 30,735 - 117,000 BTU |
|
|
| LP Gas: 30,735 - 117,000 BTU |
|
|
Minimum flow to activate | 0.6 gallons per minute (gpm) |
Flow rates | 45˚F rise @ 4.2 gpm |
| 55˚F rise @ 3.4 gpm |
| 65˚F rise @ 2.9 gpm |
| 77˚F rise @ 2.4 gpm |
| 90˚F rise @ 2.1 gpm |
|
|
Thermal Efficiency | NG: 80% LP: 80% |
Dimensions | 25.75" h x 16.75" w x 8.5" d |
Weight | 33 lbs. |
Modulating gas valve | yes |
Ignition | |
Accessories | Horizontal vent kit (AQ4) - power |
| vent kit for horizontal venting |
| |
| |
GWH 425 HN Installation Specifications | |
Gas connection | ¾" Male NPT |
|
|
Water connections | ¾" Male NPT |
NG gas pressure | Minimum: 7" W.C. |
| Maximum: 14" W.C. |
|
|
LP gas pressure | Minimum: 11" W.C. |
| Maximum: 14" W.C. |
|
|
Water pressure | Minimum: 30 PSI |
(Static) | Minimum well pressure: 40 PSI |
| Maximum: 150 PSI |
|
|
Electrical supply | 120VAC - plugs in |
|
|
Vertical venting | 5" minimum diameter - natural |
| draft |
|
|
Horizontal venting | AQ4 horizontal vent kit required |
| for horizontal terminations |
|
|
GWH 425 HN Installation Clearances
Top (A) | 12" |
|
|
Front (B) | 4" |
Back | 0" |
|
|
Sides | 4" |
|
|
Floor (C) | 12" |
|
|
LIS TED VE NT C AP
MINIMUM 6
FE ET (1.8M)
LIS TED G AS VE NT
E S TAB LIS H A ONE
F OOT R IS E B E F OR E
ANY E LB OW S
Fig. 2 Venting configuration
Installation guidelines:
Venting:
5" minimum diameter — do not reduce vent size Refer to installation manual for vent material options
Do not combination vent with any power vented appliances
Establish a one-foot rise before any elbows
Minimum vent height - 6 feet
Horizontal sections must slope upwards at least ¼" for every foot of the horizontal length and be properly supported
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 ¾"
Do not solder directly to connections on the bottom of the unit Use full port ball valves for isolation valves
Application manual 11.2007 | Bosch Water Heating |
