Gas Furnaces FAQ

Safety Notice - This is a gas-fired product, and only professionals who are qualified to work on live gas and 120v electrical equipment should do so. If you are in need of a qualified professional in your area, please use this contractor search page.

There are a number of potential causes for this symptom (Ex: Incorrect power to the furnace, door switch issue, faulty transformer, incorrectly wired thermostat, and more).

For further information and a troubleshooting flow chart, please download the Troubleshooting Guide. (PDF 2.7 MB)

Safety Notice - This is a gas-fired product, and only professionals who are qualified to work on live gas and 120v electrical equipment should do so. If you are in need of a qualified professional in your area, please use this contractor search page.

This symptom can occur if:

• The exhaust venting or termination is blocked or damaged. Please inspect and correct any issues if found.
• The low-fire pressure switch may be stuck closed or a wire may be loose. For a troubleshooting flow chart, please download the Troubleshooting Guide. (PDF 2.7 MB)

Safety Notice - This is a gas-fired product, and only professionals who are qualified to work on live gas and 120v electrical equipment should do so. If you are in need of a qualified professional in your area, please use this contractor search page.

What do these number of flashes potentially mean?

• Three flashes indicates that the low pressure switch could be stuck open.
• Six flashes indicates that a pressure switch cycle lockout has occurred.
• Thirteen flashes indicates that the high pressure switch could be stuck open.

For further information and a troubleshooting flow chart, please download the Troubleshooting Guide. (PDF 2.7 MB)

Safety Notice - This is a gas-fired product, and only professionals who are qualified to work on live gas and 120v electrical equipment should do so. If you are in need of a qualified professional in your area, please use this contractor search page.

These flashes indicate that the limit/rollout safety switch is open, and the specific number of flashes tells you for how long:

• Four flashes - Open less than five minutes.
• Five flashes - Open longer than fifteen minutes.
• Eleven flashes - Open from five minutes to fifteen minutes.

For further information and a troubleshooting flow chart, please download the Troubleshooting Guide. (PDF 2.7 MB)

Safety Notice - This is a gas-fired product, and only professionals who are qualified to work on live gas and 120v electrical equipment should do so. If you are in need of a qualified professional in your area, please use this contractor search page.

Seven flashes indicates that the system is locked out due to failure to ignite the burners.

This can occur if:

• The gas valve is not operating correctly.
• The flame sensor is not "seeing" the burner flame.
• The internal condensate trap was manufactured incorrectly.*

For further information and a troubleshooting flow chart, please download the Troubleshooting Guide. (PDF 2.7 MB)

*A small quantity of earlier units contained an incorrectly manufactured condensate trap. If the serial# on the furnace's rating label starts with three digits that are lower than "960", please refer to this service bulletin (PDF 0.5 MB) for additional information and resolution.

Safety Notice - This is a gas-fired product, and only professionals who are qualified to work on live gas and 120v electrical equipment should do so. If you are in need of a qualified professional in your area, please use this contractor search page.

Eight flashes indicates that the system is locked out due to the burner dropping out.

This can occur if:

• The gas valve is not operating correctly.
• The flame sensor is not "seeing" the burner flame.

For further information and a troubleshooting flow chart, please download the Troubleshooting Guide. (PDF 2.7 MB)

No.

Our furnace comes configured for natural gas, but a conversion kit is supplied with the product for installations where liquid propane will be the fuel type.

Instructions for the conversion can be found within the contents of the kit.

Safety Notice - This is a gas-fired product, and only professionals who are qualified to work on live gas and 120v electrical equipment should do so. If you are in need of a qualified professional in your area, please use this contractor search page.

As with all combustion equipment, there are certain maintenance points that should be checked at least once per year:

1. The exhaust venting and vent termination should be checked to ensure that there are no blockages, damage, or flue gas leaks.

2. The exhaust connector should be in place, slope upwards away from the furnace, and be free of holes, damage, or corrosion.

3. The interior of the furnace should be inspected for loose or damaged wiring.

4. The heat exchangers and fan blower should be inspected for corrosion, deterioration, or debris.

5. The return air ducting should be physically sound, fully sealed to the furnace cabinet, and terminates outside the space that contains the furnace.

6. The physical support of the furnace must be sound, with no sagging, cracks, or gaps around the base so as to provide a seal between the support and the base of the furnace.

7. There must be no obvious signs of deterioration or damage to the furnace.

8. The pilot and burner flames must be in good condition and adjusted properly.

9. The condensate drain and trap should be free of leaks or cracks.

10. Drain the trap, clean it, and fill with fresh water.

11. The flame sensor should be carefully cleaned and tested.

12. Installer-supplied air filters should be cleaned, or replaced.

For further details and specific instructions for the details listed above, please download the Installation, Operation, and Maintenance Manual. (PDF 4.2 MB)

No.

Our furnaces come configured for natural gas, but a conversion kit is supplied with the product for installations where liquid propane will be the fuel type.

Instructions for the conversion can be found within the contents of the kit.

Warning! The gas conversion process must ONLY be carried out by a service person who is qualified to work on gas combustion equipment.

If you are in need of a qualified service person in your area, please use this contractor search page.

There is indeed.

The troubleshooting guide can be found and downloaded from this page.

Warning! The troubleshooting guide is intended for use only by a service person who is qualified to work on gas combustion equipment.

If you are in need of a qualified service person in your area, please use this contractor search page.

An E5 or an E6 code showing on the error display is an indicator that something could have triggered one or more of the limits and rollout safety switches inside the furnace.

Potential causes:

• Blocked venting or burner.
• Incorrect fan speed setting.
• Defective fan.
• Loose wiring between the switches and the control board.
• Defective switches.

For full testing details and flow diagrams, please visit this page and download the BGH96 Rev.B Troubleshooting Guide.

Warning! Troubleshooting must ONLY be carried out by a service person who is qualified to work on gas combustion equipment.

If you are in need of a qualified service person in your area, please use this contractor search page.

An E7 or an E8 code showing on the error display is an indicator that the furnace is locking out after a failed attempt to ignite when called to.

Potential causes:

• Gas supply problem.
• Ignitor problem.
• Dirty flame sensor.
• Loose or faulty wiring.
• Gas orifices clogged.
• Poor grounding.
• Condensate not draining correctly.

For full testing details and flow diagrams, please visit this page and download the BGH96 Rev.B Troubleshooting Guide.

Warning! Troubleshooting must ONLY be carried out by a service person who is qualified to work on gas combustion equipment.

If you are in need of a qualified service person in your area, please use this contractor search page.

A "PR" code indicates that the polarity of the installer-supplied line voltage wiring into the furnace is incorrect.

• Please investigate the line voltage wiring that you have installed between your local disconnect and the furnaces power input terminals and ensure that the polarity is correct.
• If the issue persists, we recommend that you then ensure that the wiring polarity between the local disconnect and the property's circuit breaker panel is correct.

Warning! Troubleshooting must ONLY be carried out by a service person who is qualified to work on gas combustion equipment and line voltage systems.

If you are in need of a qualified service person in your area, please use this contractor search page.

To enhance the resilience of our supply chain network and ensure consistent product availability, we have updated the material numbers for the products below. This change helps us better manage our manufacturing capacities, ensure reporting responsibilities, and meet demand while minimizing disruptions.

What specific products are affected by this change?

The product families affected by this change include:

• IDS
• IDP
• Furnaces
• Minisplits

How do I identify the updated material numbers?

To help you identify the updated material numbers, we have added a letter at the end of the existing 10-digit material number. This letter indicates the adjustment in our manufacturing process.

Example:

• 8733962670 – Original material number
• 8733962670A – Updated material number with "A" added at the end to identify alternate manufacturing site A
• 8733962670B – Updated material number with "B" added at the end to identify alternate manufacturing site B

Will the product specifications or quality change?

No, the product specifications and quality standards remain the same. The changes in material numbers are solely for internal tracking and supply chain management purposes. You can be confident that you are receiving the same high-quality products you have come to expect from Bosch.

We appreciate your understanding and continued support. If you have any further questions, please do not hesitate to contact our customer service team.

Which part number should customers use when placing an order?

Customers should continue submitting orders with the original part number. They will be contacted by a member of our Customer Service or Sales team if another part number is needed.

Will the list price be any different?

No, the list price will remain the same.

This is a great duel-fuel pairing that we highly recommend!

Please visit this product page for further information regarding the Bosch BGH96 Rev.C (R-454B) gas furnace.

There you will find descriptions of the furnace and its benefits, and also links to key technical literature including the product brochure, which contains sizing and recommended pairing tables.

Warning! The gas conversion process must ONLY be carried out by a service person who is qualified to work on gas combustion equipment.

If you are in need of a qualified service person in your area, please use this contractor search page.

No.

Our furnaces come configured for natural gas, but a conversion kit is supplied with the product for installations where liquid propane will be the fuel type.

Instructions for the conversion can be found within the contents of the kit.

The Bosch BGH96 Rev.C gas furnace can be used with our new R-454B cased coils as well as our previous R-410A cased coils.

When paired with a Bosch R-454B cased coil though, you must do the following as part of the installation of the system:

• Locate the refrigerant leak sensor that is installed on the coil.
• Run the cable from the cased coil's leak sensor to the furnace's control board and connect it to "CN30".
• Locate DIP switch "SW1-2" on the furnace's control board and change the position to "ON".

For diagrams and further instructions, please review the installation manual supplied with the furnace.

If you no longer have the hard copy of the manual, a PDF version can be downloaded from this page.

You can indeed.

As with pairing the furnace with a Bosch R-454B cased coil, you must ensure that you are connecting the 3rd party coil's refrigerant leak sensor to the Bosch furnace's control board as part of the system installation:

• Locate the refrigerant leak sensor that is installed on the 3rd party coil.
• Run the cable from the cased coil's leak sensor to the furnace's control board and connect it to "CN30".
• Locate DIP switch "SW1-2" on the furnace's control board and change the position to "ON".

For diagrams and further instructions, please review the installation manual supplied with the furnace.

If you no longer have the hard copy of the manual, a PDF version can be downloaded from this page.

Firstly we'll assume that you've wired the coil's leak detector back to the CN30 interface on the furnace's control board and correctly set the SW1-2 DIP switch to the "ON" position.

If the cased-coil's refrigerant leak sensor detects a higher level of refrigerant in the unit, the following will take place:

• The "LED2" indicator will repeat two green blinks.
• The Y-call will cancel and stop the refrigerant circulation.
• The furnace's blower will remain running until the detected refrigerant level drops to a safe value.

If this occurs, please do the following:

• Ventilate the area.
• Avoid open flames being present.
• Contact your installer and have them inspect the cased coil, including refrigerant piping and connections, for evidence of a leak.

If you are in need of a qualified service person in your area, please use this contractor search page.

For further instructions, please review the installation manual supplied with the furnace.

If you no longer have the hard copy of the manual, a PDF version can be downloaded from this page.

Yes, we have included several refrigerant leak sensing flash codes that will appear on the furnace control board's "LED2" indicator:

1 Green Flash - Communication with the refrigerant leak sensor has been lost for at least 2 minutes.

• The "LED2" indicator will repeat a single green blink.
• The Y-call will cancel and stop the refrigerant circulation.
• Check for damage to the refrigerant leak sensor.
• Ensure that the wiring from the sensor is undamaged and is connected firmly to the furnace control board's CN30 port.
• If damage is found, please replace the damaged part.

2 Green Flashes - Potential Refrigerant Leak

• The "LED2" indicator will repeat two green blinks.
• The Y-call will cancel and stop the refrigerant circulation.
• The furnace's blower will remain running until the detected refrigerant level drops to a safe value.
• Ventilate the area.
• Avoid open flames being present.
• Contact your installer and have them inspect the cased coil, including refrigerant piping and connections, for evidence of a leak.

3 Green Flashes - DIP Switch SW1-2 Is Incorrectly Set

• The "LED2" indicator will repeat three green blinks.
• If you have a case coil's refrigerant leak sensor wired back to the CN30 port on the furnace's control board, you must also set the board's SW1-2 DIP switch to the "ON" position.
• If it is still set to the "OFF" position, change it to "ON".

4 Green Flashes - Refrigerant Leak Sensor Faulty Or Has Exceeded Its Life Cycle

• The "LED2" indicator will repeat four green blinks.
• The Y-call will cancel and stop the refrigerant circulation.
• Ensure that the refrigerant sensor is correctly installed and no damage is evident.
• If the problem persists, replace the refrigerant leak sensor.

For further information, please review the installation manual supplied with the furnace.

If you no longer have the hard copy of the manual, a PDF version can be downloaded from this page.

If you are in need of a qualified service person in your area, please use this contractor search page.

This is typically a condition that is triggered when the SW1-2 DIP switch on the board is set to "ON" without an A2L refrigerant leak sensor being wired to the board's CN30 connector.

• If you have not installed the furnace with a Bosch R-454B cased coil and therefore have no A2L sensor connected to CN30, set the SW1-2 DIP switch to "OFF".
• If you have installed the furnace with a Bosch R-454B cased coil and therefore do have an A2L sensor connected to CN30, set the SW1-2 DIP switch to "ON".

For further information, please review the installation manual supplied with the furnace.

If you no longer have the hard copy of the manual, a PDF version can be downloaded from this page.

If you are in need of a qualified service person in your area, please use this contractor search page.