Bosch Compress H01-5239 fault code
Bosch Compress heat pumps
What it means
DHW temperature sensor TW1 fault
A warning. Sensor TW1 or its cable reads shorted or broken.
UK models this code applies to
From the Bosch service literature we hold (Worcester Bosch user interface HPC 410 manual 6721832682 (2021/02) §8 Unit troubleshooting, Table 41) — not a scraped list.
Compress 3400i AWS 4 kW (CS3400iAWS 4 OR-S)Compress 3400i AWS 6 kW (CS3400iAWS 6 OR-S)Compress 3400i AWS 8 kW (CS3400iAWS 8 OR-S)Compress 3400i AWS 10 kW (CS3400iAWS 10 OR-S)Compress 5800i AW 4 kW (CS5800i AW 4 OR-S)Compress 5800i AW 5 kW (CS5800i AW 5 OR-S)Compress 5800i AW 7 kW (CS5800i AW 7 OR-S)Compress 7001i AW 5 kW (CS7001iAW 5 OR-S)Compress 7001i AW 7 kW (CS7001iAW 7 OR-S)Compress 7001i AW 9 kW (CS7001iAW 9 OR-S)Compress 7001i AW 13 kW (CS7001iAW 13 OR-S)Compress 7001i AW 17 kW 3-phase (CS7001iAW 17 OR-T)
Now the harder half: proving what caused it
H01-5239 names a symptom, not a root cause. In the app, the same code opens a guided investigation: what to measure first, the expected values for your exact model, and an honest verdict — including “nothing in this machine is broken” when that's what the readings say.
Chase this code in the app →