BoilerFaultCodes Excessive temperature on primary circuit
Excessive temperature on primary circuit
Biasi Parva 28S Fault codes & diagnostics
13 fault codes with plain-English explanations, severity ratings, DIY guidance, and repair cost estimates.
Combi Natural Gas 28 kW 2001 onwards Discontinued
GC Numbers 41-583-0547-970-14
Download the Biasi Parva 28S 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. 13 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 |
|---|---|---|
| 47-970-14 | Parva M90 28S | 2001–present |
| 41-583-05 | Parva HE Systen M96.28SR/P | 2007–present |
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 Biasi Parva 28S faults?
The top 6 problems in plain English — with causes, DIY checks and repair costs.
Fault codes
All 13 documented codes
Tap any card for details
Faulty air pressure switch
Faulty air pressure switch
Faulty c.h. temperature probe NTC
Faulty c.h. temperature probe NTC
Faulty d.h.w temperature probe NTC
Faulty d.h.w temperature probe NTC
Faulty Electronic control/ignition p.c.b.
Faulty Electronic control/ignition p.c.b.
Faulty flue temperature probe NTC
Faulty flue temperature probe NTC
Faulty primary circuit
Faulty primary circuit (no water or absence of flow)
Faulty primary circuit (no water or absence of flow)
Faulty primary circuit (no water or absence of flow)
Flue temperature probe NTC lockout
Flue temperature probe NTC lockout
Lack of burner ignition
Lack of burner ignition (no ignition signal from the full sequence ignition device)
Lack of power supply
Lack of power supply or faulty electronic control p.c.b.
Lack of power supply or faulty electronic control p.c.b.
Lack of power supply or faulty electronic control p.c.b.
Safety thermostat lockout
Safety thermostat lockout