BoilerFaultCodes A01
Ignition failure
Ariston ACO 27 MFFI Fault codes & diagnostics
30 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Gas 2004 onwards Discontinued
GC Number 47-116-34
Download the Ariston ACO 27 MFFI manual
PDF
Versions & GC numbers
The fault code is already on your display
Note it down before pressing reset — resetting clears the code immediately. How to read fault codes →
Severity at a glance
Each cell = one fault code. Hover to identify. 30 Unrated
Which version do you have?
The GC number on your boiler's data badge identifies the exact appliance and production years, as recorded in the UK Product Characteristics Database.
| GC number | Appliance (register name) | Produced |
|---|---|---|
| 47-116-34 | ACO 27 MFFI | 2004–2007 |
Appliance names and production years are taken from the UK Product Characteristics Database (the SAP/SEDBUK register). Where a GC number is also printed in this model's own manufacturer manual, both sources were checked to agree.
Just want the most common Ariston ACO 27 MFFI faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes
All 30 documented codes
Tap any card for details
A02
FLOW TEST FAILED
A33
check the fan cable, replace the fan, or replace the main P.C.B.
AA01
Too many attempts to ignite on starting up
AA02
No water or no water circulation in central heating system
AA03
The heating flow temperature exceeds 105°C during operation
AA07
Too many failures to flame in one period during operation
AA33
Problem with the fan
AA97
Problem with the electronic monitoring
AA98
Problem with the electronic monitoring
Showing 11–20 of 30
AA99
Problem with the electronic monitoring
E08
boiler shutdown both in D.H.W.mode and C.H.mode due to under floor heating thermostat contact opening
E33
Air pressure switch failure (check exhaust flue duct, APS cable, condensate in silicone pipes, or replace APS/main P.C.B.)
E95
test failed
EE04
Domestic hot water temperature probe in open circuit
EE05
Domestic hot water temperature probe in short circuit
EE06
Heating flow temperature probe in open circuit
EE07
Heating flow temperature probe in short-circuit
EE08
Heating return temperature probe in open circuit
EE09
Heating return temperature probe in short-circuit
Showing 21–30 of 30
EE10
Under floor heating temperature probe in open circuit
EE20
Flame detected with gas valve closed
EE30
Outdoor sensor open circuit
EE31
Outdoor sensor in short circuit
EE33
Fan operation sensed with no demand for central heating or domestic hot water
EE34
Fan operation but air pressure switch does not close
EE80
Remote Control CLIMAMANAGER room sensor in open circuit or short circuit
EE94
Problem within the electronic system
EE95
Error reading flow or return temperature probe
EE99
Problem within the electronic system