Radson fault code Ad
Fault code Ad on a Radson boiler (including Radostar) means: Domestic hot water sensor fault. 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 Radson boiler indicates: Domestic hot water sensor fault.
Fixing fault code Ad: step by step
- Reset the appliance once; a one-off measuring error will then clear.
- Where you can reach it without opening the sealed combustion section, check that the sensor plug is seated firmly and the wiring is undamaged.
- If the code comes back, the sensor or its wiring is usually faulty (short or open circuit). Sensors in the sealed combustion section should be replaced by a qualified heating engineer.
Applies to
Radson Radostar, EHLE 17, EHLE 23, EHLE 27, EHLE 34, EHLE 39, EHLE 78.
Click a model for the parts list and exploded view of that appliance.
Matching parts
Radson parts are available from Instalpunt; shipping to EU countries from €12.95 (€16.95 for more distant countries), usually 3–5 working days.
Based on the cause, these original Radson parts fit (always check the type number of your appliance):
- Bosch plug for NTC € 33.98
- Bosch NTC flow € 58.44
Further reading on this cause
Other Radson codes with the same cause
- 7 — NTC 1 or 2 open circuit or short circuit
- 8 — NTC 2 open circuit or short circuit
- A6 — Flue gas NTC (4)
- A7 — Return NTC (2) defective
- CC — Outdoor sensor defective
- E1 — NTC (1) too high
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 Radson boiler fault code Ad mean?
Domestic hot water sensor fault.
How do I fix fault code Ad on a Radson 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 Radson fault code Ad?
That depends on the exact cause. In the Radson 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 Radson boiler faults and codes at a glance →