Bosch fault code Ad
Fault code Ad on a Bosch boiler (including HRC and ZSE) means: Cylinder NTC 1 is not recognised. Reset the appliance once. If the code comes back, a part is usually faulty, often a temperature sensor. You can check the water pressure and settings yourself; leave work on gas-carrying parts to a certified gas engineer.
After a safety alert (gas, flue gas, combustion), reset no more than once and call in a certified gas engineer. If you smell gas, call your national gas emergency number or 112 immediately.
Cause
Fault code Ad on a Bosch boiler indicates: Cylinder NTC 1 is not recognised.
Applies to
Bosch HRC, ZSE, ZSN, ZWE, ZWN, 18-6 KE, 24-4, 24-4 MFA, 24-4 MFK, 24-6 KE, 24-7 KE, 26, 28-4 MFA.
Fault code Ad on other Bosch series
The same code does not mean the same thing on every series. Check the rating plate to see which series you have:
- Ad on EHLE, 17, 23, 27, 34, 39: Domestic hot water NTC fault.
- Ad on Turbo Tower, 30 HRC, 30 HRC II: Cylinder temperature sensor 1 defective.
- Ad on TOP, 28-3 ZSB, 30-3 ZWB, 42-3 ZB, 42-3 ZWB: Cylinder NTC not recognised. The cylinder NTC was first recognised on the Heatronic 3 as a bus device and then connected to IPM 1 or IPM 2.
- Ad on VRC, 24 Open: Cylinder sensor not recognised.
Matching parts
Bosch parts are available from Instalpunt; shipping to EU countries from €12.95 (€16.95 for more distant countries), usually 3–5 working days.
For fault code Ad, the part involved is usually in the category: sensor.
Based on the cause, these original Bosch parts fit (always check the type number of your appliance):
- Bosch spring for NTC flow sensor € 10.87
- Bosch NTC sensor/flow € 55.72
- Bosch differential pressure sensor ZWE 24AE € 58.44
Further reading on this cause
Other Bosch codes with the same cause
- --341 — The temperature measured by the flow temperature sensor or the return temperature sensor…
- 1022 W — Storage cylinder temperature sensor defective or contact problems
- 1025 W — Return temperature sensor defective
- 1037 W — Outdoor temperature sensor defective, substitute mode heating active
- 1065 W — Water pressure sensor defective or not connected
- 1068 W — Outdoor temperature sensor or lambda sensor defective.
Fix it yourself or call an engineer?
Always consult the manual for your appliance and work safely. If in doubt or if the fault comes back, call in a qualified professional. A question about a part? Write to us at info@instalpunt.nl.
Frequently asked questions
What does Bosch boiler fault code Ad mean?
Cylinder NTC 1 is not recognised.
How do I fix fault code Ad on a Bosch boiler?
First check the cause described above. Then restart the appliance using the reset button. If the message comes back, a part usually needs replacing or the fault needs to be repaired by a qualified professional.
Which parts do I need for Bosch fault code Ad?
That depends on the exact cause. In the Bosch parts overview at Instalpunt you will find the current price and stock for each part.
Can I fix fault code Ad myself?
You can reset the appliance and check things like the water pressure or settings yourself. Work on gas-carrying parts must be left to a certified gas engineer.
All Bosch boiler faults and codes at a glance →