Water is too hot | Bosch Appliances Model GWH 425 instruction

Troubleshooting

6.7Water is too hot

1.Verify gas type indicated in rating sticker located on right-hand side of cover, coincides with the gas type you are using. NG is a natural gas unit and LP is for liquid propane.

2.Adjust the gas control slide button from three flame position towards the one flame position for cooler temperatures. If the water is still too hot, the temperature adjustment knob on the water heater maybe set too high. Lower the setting and test water temperature. This dial turns counter clockwise for lower temperatures and clockwise for higher temperatures.

3.Inlet water is preheated. This model does not have a thermostat and thus will not modulate flame height in order to prevent over heating. It is designed for a cold water feed only. Replumb the heater with cold water to the inlet.

4.Increase the flow rate. Restrictions in the water path can slow the flow of water through the heater, resulting in very hot outlet temperatures. Restrictive showerheads and faucet aerators should be cleaned out or upgraded with less restrictive ones. In addition, the water heater's inlet filter should be cleaned and inspected (see chapter 5.2).

5.If water is still too hot, consult service bulletins on www.boschpro.com to lower outlet temperatures further.

6.If the water has a high mineral content, the heat exchanger may be scaled internally. This restricts the water path, causing the water to boil and produce extremely hot temperatures. Instructions for descaling

the heat exchanger are available at www.boschpro.com.

6.8Water is not hot enough

1.Verify gas type indicated in rating sticker located on right-hand side of cover, coincides with the gas type you are using. NG is a natural gas unit and LP is for liquid propane.

2.Flow at one particular tap is too great or too many fixtures are running at one time. Lower flow to stay within heater's specifications.

3.Ensure the gas control slide button is all the way to the right. In addition, the temperature adjustment knob on water heater maybe set too low. Turn the knob clockwise for higher temperatures and test the water temperature.

4.Shut off installer supplied cold water shut off valve (if none installed, install before proceeding). Open all hot water taps supplied by the heater. Wait 5 minutes and check all taps. Any water running is a sign of a plumbing crossover. Consult a local plumber or service person for help in correcting a plumbing crossover.

5.Inspect the water path outside of the heater for obstructions. Make sure all outlets (i.e. showerheads,

faucet aerators and whole house filters) are clear of debris. Also, the water heater's inlet filter screen should be inspected and cleaned (see chapter 5.2)

6.The water valve may be dirty, prohibiting it from fully opening the gas valve. This part needs to be periodically serviced (every 2-5 yrs depending on water quality and use) (see chapter 5.2).

7.Gas pressure is too low. Ensure gas pressure is in accordance with manufacturer's specifications (see chapter 3.9). A gas pressure reading is needed to proceed further. Contact your original installer or a local certified gas technician to obtain this reading.

6.9Burners ignite without hot water flow

1.The water valve may be dirty and sticking, prohibiting it from fully closing the gas valve. This part needs to be periodically serviced (every 2-5 yrs depending on water quality and use) (see chapter 5.2).

6.10 Low hot water pressure

1.Confirm adequate flow rate through the unit. With cold supply shut off to the unit, disconnect hot outlet side to the unit. Place a half gallon jug under hot outlet to catch water. Open cold supply and measure flow rate out of the unit. With temperature adjustment knob set all the way clockwise, the flow rate should be close to 2gpm, filling the jug in 15 seconds. With the temperature adjustment knob set all the way counterclockwise, the flow rate should be close to 4gpm, filling the jug in 7 seconds. If the flow rate is not adequate, inspect and clean the inlet filter screen (see chapter 5.2).

2.Confirm the incoming water pressure to the unit is above the required 30psi.

3.Inspect the water path outside of the heater for obstructions. Make sure all outlets (i.e. showerheads, faucet aerators and whole house filters) are clear of debris.

4.Be sure to run only one major application at a time with this unit. Opening too many taps at one time can disperse water flow resulting in a diminished flow/ pressure at all outlets.

5.If the water has a high mineral content, the heat exchanger may be scaled internally. This restricts the water path, causing diminished water flow. Instructions for descaling the heat exchanger are available at www.boschpro.com.

6.11 Noise when heater is running

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