Vent piping | Bosch Appliances GWH 1600 P, GWH 425 HN, GWH 425 PN

AQ4 Installation instructions

2.5 Vent piping

1.Install 5" to 4" reducer pipe on top of the water heater and then connect a 4" 90º elbow to begin the horizontal run. Use 4" vent pipe to connect from this elbow to the power vent motor inlet, avoiding elbows wherever possible. The maximum vent length from the water heater to the point of termination is 25 feet. (Fig. 5) If using more than one 90° elbow, subtract 5 feet off the maximum vent length for each additional elbow used. A maximum of three elbows is allowed. The minimum vent length is 2 ft.

2.Support the vent pipe in accordance with vent pipe manufacturer’s instructions. Vent pipe is not supplied in the power vent kit, with the exception of the 5" to 4" reducer in the AQ4 kit. Observe the clearances associated with the class of vent pipe used. 4” single wall galvanized, 4” stainless steel or 4” B-vent pipe is required.

2.6 Linear safety spillage switch

The linear safety spillage switch provides a means for safety shut down of the water heater in the event of flue blockage or power vent failure. If hot flue gases spill from the draft hood diverter, the draft spillage sensing switch will open the pilot safety circuit and shut off all gas to the water heater. The switch is normally closed and opens at temperatures greater than 185º F. It has a manual reset button.

Mounting the linear safety spillage switch

1.Attach the spillage switch to the top left of the heater’s draft diverter using the existing hole and the included mounting screw. (Fig. 6)

2.Lay copper capillary sensing tube across top of the draft diverter. Allow excess tube to hang down right side of hea ter. Do not cut or crimp capillary tube.

3.Route the two wires from the spillage switch down the left side of heater to the ECO keeping the cables out of contact with hot surfaces. (Fig. 6)

Connecting linear safety spillage switch to pilot safety circuit

The ECO/temperature limiter is mounted on the lower left outlet water pipe. (Fig. 7)

1.Remove one wire lead connected to ECO terminal (it does not matter which one is disconnected).

2.Attach 1/4" quick connect terminal end of linear spill switch cable to now exposed terminal of the ECO.

3.Connect the male spade connector to the removed lead wire from step 1. See the wiring diagram in Fig. 13 to confirm proper set up.

Fig. 5 Venting setup

Fig. 6 Linear safety spillage switch mounting

ECO terminals

Fig. 7 ECO location

AQ4 Manual

GWH 425 PN, GWH 1600 P, GWH 1600 H, GWH 425 HN specifications

Bosch Appliances have long been synonymous with innovation and reliability in the realm of home comfort solutions. Four notable models in their range of gas water heaters are the GWH 425 HN, GWH 1600 H, GWH 1600 P, and GWH 425 PN. Each unit is developed to meet diverse user needs while providing the highest levels of efficiency and performance.

The Bosch GWH 425 HN is a high-capacity unit catering to larger households or commercial environments. With an impressive heat output, this model ensures a consistent hot water supply when needed. Key features include advanced combustion technology for enhanced efficiency and reduced emissions, making it an environmentally-friendly choice. Its compact design allows for flexible installation options, fitting seamlessly into tight spaces. Additionally, the unit is equipped with an intelligent control system that optimizes performance based on usage patterns.

Moving on to the Bosch GWH 1600 H, this water heater is perfectly suited for smaller homes and apartments. It combines user-friendly operation with energy-saving capabilities. This model utilizes a unique modulating burner system that adjusts the flame intensity according to water demand, significantly lowering energy consumption. Furthermore, the GWH 1600 H incorporates a built-in safety system that ensures optimal operation under varying conditions.

The Bosch GWH 1600 P offers a similar capacity as the GWH 1600 H but with added digital functionalities. Users can expect advanced temperature settings and real-time monitoring through an intuitive digital display. This model prioritizes ease of use, allowing homeowners to customize their hot water experience effortlessly. The GWH 1600 P also reflects Bosch’s commitment to durability, featuring robust construction suitable for various environmental conditions.

Lastly, the Bosch GWH 425 PN is another versatile choice for those needing robust hot water production. It shares many characteristics with the GWH 425 HN, like high efficiency and smart technology. However, it distinguishes itself with innovative low-NOx technology, reducing nitrogen oxide emissions to meet stringent environmental regulations.

In summary, Bosch's GWH 425 HN, GWH 1600 H, GWH 1600 P, and GWH 425 PN represent a diverse selection of gas water heaters designed to suit different household needs. Whether it’s for a larger family or a compact apartment, these models provide efficient and reliable hot water solutions while employing advanced technologies to minimize environmental impact. With their focus on quality and customer satisfaction, Bosch Appliances continues to lead the way in the hot water industry.