{"id":8245,"date":"2022-03-21T03:32:45","date_gmt":"2022-03-21T03:32:45","guid":{"rendered":"https:\/\/notsealed.com\/?p=8245"},"modified":"2023-07-31T07:07:51","modified_gmt":"2023-07-31T07:07:51","slug":"diy-bosch-tankless-water-heater-troubleshooting-error-codes-explained","status":"publish","type":"post","link":"https:\/\/notsealed.com\/diy-bosch-tankless-water-heater-troubleshooting-error-codes-explained.html","title":{"rendered":"DIY Bosch Tankless Water Heater Troubleshooting Error Codes Explained."},"content":{"rendered":"\n
There are many different types and sizes of Bosch tankless water heaters on the market. Most have an excellent error displayed to help you diagnose the problem.<\/p>\n\n\n\n
As an electrician, I am often called to diagnose problems with instant hot water units. Also called tankless water heaters. These are very reliable and will tend to last 10-20 years or more.<\/p>\n\n\n\n
I have listed some of the more common error code faults you will come across with some simple repair guides. So read on for our mega Bosch tankless water heater troubleshooting guide.<\/p>\n\n\n\n
Abnormal combustion. Confirm blockage in either air intake or exhaust. Check the air fan for correct operation.<\/p>\n\n\n\n
No detection of initial flame. The Bosch gas hot water fault code 11 signifies that there is a fault with the unit\u2019s ignition. In this instance, your Bosch hot water heater will not operate and won\u2019t produce hot water until Bosch fault code 11 has been investigated and repaired.<\/p>\n\n\n\n
Flame failure safety device working. Check combustion condition, gas solenoid valve, flame failure safety device, earthing of PCB.<\/p>\n\n\n\n
Overheating protection device activated. Check the wires to the over temp sensor. Check the water pressure and flow rate. Check the exhaust for restrictions. Activates at 184 deg Celsius.<\/p>\n\n\n\n
The remaining flame safety device is activated. Check the cabling.<\/p>\n\n\n\n
Problem: Something in the unit’s neutralizer is clogged.<\/p>\n\n\n\n
Solution: Try resetting the controller by turning the main power off and on. A flush of the system may be required. You should plan on changing your filler for the condensate capsule at least once per year. Damage to equipment and drains could happen if you don’t replace the unit’s neutralizer regularly.<\/p>\n\n\n\n
I use this tankless hot water flushing kit<\/a> with some white vinegar for my client’s gas hot water units.<\/p>\n\n\n\n Abnormal inlet water thermistor. Measure the resistance of the water temperature thermistor. A short circuit is failed. May be hard to find this sensor as it may be behind other electronic parts and pipes.<\/p>\n\n\n\n Abnormal outlet water thermistor. Measure the resistance of the water outlet temperature thermistor. A short circuit is failed. Check terminals for corrosion.<\/p>\n\n\n\n Abnormal combustion fan. Check the fan pulse rate sensor. Also known as an under-speed proximity switch. Check all connections, possible restriction of the fan, or failure of the PCB. The target speed is 500 RPM.<\/p>\n\n\n\n Abnormal water volume adjusting valve. Confirm the limiter of water adjusting valve. Check connections. Make sure the water inlet volume and pressure are correct. The minimum water flow for correct operation is 2.5L minute. <\/p>\n\n\n\n Check for scale build-up and flush if necessary. In fact, if your hot water has never been flushed or it has been longer than 5 years between flushing I would get it done. I use this tankless hot water flushing kit from amazon.<\/a> It could save you thousands in repair or replacement hot water plumbing bills.<\/p>\n\n\n\n The abnormal driving circuit of a gas solenoid valve. Control fault of the driving circuit of the gas solenoid valve. Check for ground faults or faulty PCB.<\/p>\n\n\n\n Abnormal flame failure safety device circuit (artificial flame.) Measure flame current at extinguish.<\/p>\n\n\n\n Abnormal PCB setup. Check all dip switches are set correctly to the operating manual for the country\/area. Check gas changing connector and temp changing connector.<\/p>\n\n\n\n Abnormal remote control communication from the main controller to the gas hot water unit. Check the cable has not been damaged and is free of corrosion on all the terminals. These remote temperature controllers are prone to failure if moisture has found its way onto the internal PCB.<\/p>\n\n\n\n Disconnect the controller and clean the PCB of corrosion. Replace the Bosch temperature remote controller if required. You can still run the Bosch hot water systems but it will be at a set temperature. Often defaults to 55 deg Celcius. <\/p>\n\n\n\nBosch Tankless Water Heater Error Code 31<\/h2>\n\n\n\n
Bosch Tankless Water Heater Error Code 32<\/h2>\n\n\n\n
Bosch Water Heater Error Code 61<\/h2>\n\n\n\n
Bosch Water Heater Error Code 65<\/h2>\n\n\n\n
Bosch Water Heater Error Code 71<\/h2>\n\n\n\n
Bosch Water Heater Error Code 72<\/h2>\n\n\n\n
Bosch Water Heater Error Code 73<\/h2>\n\n\n\n
Bosch Water Heater Error Code 760, 76, 0<\/h2>\n\n\n\n