- Boilers
- Gas boiler
501
Chaffoteaux 501 on a gas boiler: no flame
Risk level
High
Professional inspection is recommended.
Urgency
High
Quick answer
Chaffoteaux 501 means no flame: the boiler has locked out and does not reset by itself. Check the gas tap is open and press RESET; if the lockout repeats, switch the boiler off, close the gas and call the service centre.
Safety first
Stop and check this first
- If you smell gas: Chaffoteaux says to close the main gas tap, open the windows and call the technician. Do not operate switches or light flames, leave the home and call your gas distributor's emergency number from outside. If you smell burning or see smoke, cut the power, close the gas and ventilate.
- If 501 repeats, stop resetting: Chaffoteaux says to switch the boiler off, disconnect it at the external switch, close the gas and call the service centre. Do not open the boiler.
Safe checks you can perform
- Gas smell before resetting
- Gas tap and supply
- Reset with RESET
- Ignition check by the technician
Leave these tasks to a qualified professional
- Do not attempt this professional task: Gas pressure measurement
- Do not attempt this professional task: Combustion analysis after the repair
- Do not attempt this professional task: Ignition and flame signal check
What a technician must be able to justify
Technician visit
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
Gas pressure measurement
What they doThe technician measures gas pressure at the boiler's test point with a gauge and compares it with Chaffoteaux's specification.
They must show youthe measured value against the specification.
In writingthe pressure measured.
Combustion analysis after the repair
What they doThe technician measures CO2 or O2 and CO with an analyser.
They must show youthe analyser printout.
In writingthe values in the installation log.
Ignition and flame signal check
What they doThe technician checks the ignition system and measures the flame detection signal.
They must show youthe flame signal reading.
In writingwhat was cleaned or replaced and why.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Follow these steps
Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
Gas smell before resetting
- Who:
- you.
- How:
- without touching switches, notice whether it smells of gas near the boiler.
- Result that matters:
- whether there is a gas smell.
- If it smells of gas:
- do not reset; follow the gas warning on this page.
- If there is no smell:
- check the gas tap.
- Evidence to keep:
- a note of the time and what you noticed.
Evidence: Chaffoteaux Pigma Advance y Pigma Ultra, manual de usuario
Gas tap and supply
- Who:
- you.
- How:
- check the boiler's gas tap is open and whether the hob or another gas appliance works.
- Result that matters:
- whether gas reaches the boiler.
- If it was closed or there is no gas at home:
- open it or contact your distributor.
- If there is gas:
- the fault is in the boiler.
- Evidence to keep:
- a photo of the tap and a note of whether the hob worked.
Evidence: Chaffoteaux Pigma Advance y Pigma Ultra, manual de usuario
Reset with RESET
- Who:
- you.
- How:
- press the RESET button on the panel, as Chaffoteaux says for non volatile errors. Do it once.
- Result that matters:
- whether the boiler runs again.
- If it runs and does not repeat:
- note the date.
- If 501 returns or happens often:
- switch the boiler off, set the external switch to OFF, close the gas and call the service centre.
- Evidence to keep:
- a photo of the display with 501 and the time of each reset.
Evidence: Chaffoteaux Pigma Advance y Pigma Ultra, manual de usuario
Ignition check by the technician
- Who:
- authorised gas technician.
- How:
- measures gas pressure and checks ignition and flame detection.
- Result that matters:
- whether the problem is gas or the boiler.
- If gas pressure is too low:
- it is a supply problem.
- If it is correct:
- it points to ignition or flame detection.
- Evidence to keep:
- a report with the pressure measured and the repair.
Chaffoteaux reserves repairs for its technical service or a qualified technician: opening the boiler is not the user's job.
Evidence: Chaffoteaux Pigma Advance y Pigma Ultra, manual de usuario
Still not solved
If the error persists, stop here. See what the technician must do and show you.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- Boilers
- Brand
- Chaffoteaux
- Product type
- Gas boiler
Known code variants
- 5 01
- Ariston 5 01
- Ariston E501
- Chaffoteaux 5 01
- Clas One 501
- Error 501 Ariston
- Error 501 Chaffoteaux
- Pigma 501
What it means
In the Pigma Advance error table, 501 is no flame, a lockout error. Chaffoteaux explains this type of error is non volatile: it does not clear automatically and you must press RESET on the control panel to restore operation. The boiler needs gas and a detected flame to keep running; the code says no flame was detected, not why.
Warnings and stop conditions
- Criticaleditorial warning
If you smell gas: Chaffoteaux says to close the main gas tap, open the windows and call the technician. Do not operate switches or light flames, leave the home and call your gas distributor's emergency number from outside. If you smell burning or see smoke, cut the power, close the gas and ventilate.
Evidence: Chaffoteaux Pigma Advance y Pigma Ultra, manual de usuario
- Highsource verified
If 501 repeats, stop resetting: Chaffoteaux says to switch the boiler off, disconnect it at the external switch, close the gas and call the service centre. Do not open the boiler.
Evidence: Chaffoteaux Pigma Advance y Pigma Ultra, manual de usuario
Symptoms and causes
Probable causes · in order
- Gas closed or no supplyCommon
No gas, no flame. It fits if the boiler's gas tap is closed or other gas appliances at home do not work either.
Evidence: Chaffoteaux Pigma Advance y Pigma Ultra, manual de usuario
- Ignition or flame detection failurePossible
If gas arrives and the boiler still locks out, the fault is inside, in ignition or flame detection; only the technician can check it.
Evidence: Chaffoteaux Pigma Advance y Pigma Ultra, manual de usuario
Virtual technician
Does 501 still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
- 1
Chaffoteaux Pigma Advance y Pigma Ultra, manual de usuario
Chaffoteaux · 2018 · manual
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