How do I know if this pressure switch is for my boiler?

Verify the reference 995903 printed and ensure your model is on the list of compatible ones; also compare the connections with the original part. It is an Ariston / Chaffoteaux part.

The pressure switch controls the pressure/draught (of air in sealed systems) or water to authorize operation.

Is the boiler not starting or showing a draught fault?

If the fan spins but does not ignite, check the pressure tubes (loose/blocked), the diaphragm, and the fan.

Which models is it suitable for?

Part shared by various models (see Compatibility). If your model does not appear, send us a photo of the marking and we will confirm it.

Installation and recommendations

Check the tightness of the pressure pipes and the switching of the contact.

What does refurbished mean and what coverage does it have?

Part removed from a boiler out of service, inspected and tested. Includes 1-year warranty and 14-day return policy. Delivery within 2–4 working days in the EU.

What does fault code E02 mean on Ariston?

Insufficient water pressure in the circuit (safety shutdown). If the minimum water pressure switch remains open or is out of calibration, the PCB interprets insufficient pressure and triggers E02; check the switch continuity with >1 bar and inspect the tube/capillary connections for obstruction.

RefurbishedAriston Pressure switches

Ariston Minimum Water Pressure Switch Microtec T2 LLS 23 MFFI Ref. 995903

15 €VAT includedIn stock · 5 units

Pressure switch: refurbished spare part that controls air or water pressure to authorize operation. Useful if the boiler does not start or shows a draft error. Compatible with Microtec 23 MI, Microtec 23 MFFI / T2 LLS 23 MFFI, Microgenus 21 MFFI (ref. 995903). Includes a one-year warranty and delivery within 2–4 working days in the EU.

Consult via WhatsApp

Not sure if it's your part? Send us a photo of the screen printing via WhatsApp and we'll confirm compatibility before you purchase.

Delivery in 2–4 working days

1-year warranty

14-day return

Technical support

Key Data

Reference: 995903
Brand: Ariston
Type of part: Pressure switches
Available units: 5 units in stock
Status: Refurbished
Warranty: 1 year
Shipping: 2–4 working days (EU)
Return: 14 days

The same part (ref. 995903) equips these models. Verified compatibility; check the reference before purchasing.

Ariston

Microtec 23 MI
Microtec 23 MFFI / T2 LLS 23 MFFI
Microgenus 21 MFFI
Microgenus 28 MFFI
Microgenus 31 MFFI
Microgenus Plus 24 MFFI
Microgenus Plus 28 MFFI
Microgenus Plus 31 MFFI
Microgenus II 24
Microgenus II 28
Microsystem 15
Microsystem 21
Microsystem 28
Selecta 24 MFFI
Modula 23

Chaffoteaux

Talia Green HP
Talia Green System HP

Fault codes related to this part (not the entire boiler). They usually have more possible causes: first rule out electrodes, wiring/connections, and gas supply. Verified with ≥3 sources.

Code	What does it mean?	Cause and diagnosis (this part)
E02	Insufficient water pressure in the circuit (safety shutdown).	If the minimum water pressure switch remains open or is miscalibrated, the PCB interprets insufficient pressure and triggers E02; check the switch continuity with >1 bar and inspect the tube/capillary connections for obstruction.

How do I know if this pressure switch is for my boiler?: Verify the reference 995903 printed and ensure your model is on the list of compatible ones; also compare the connections with the original part. It is an Ariston / Chaffoteaux part.
What is it used for?: The pressure switch controls the pressure/draught (of air in sealed systems) or water to authorize operation.
Is the boiler not starting or showing a draught fault?: If the fan spins but does not ignite, check the pressure tubes (loose/blocked), the diaphragm, and the fan.
Which models is it suitable for?: Part shared by various models (see Compatibility). If your model does not appear, send us a photo of the marking and we will confirm it.
Installation and recommendations: Check the tightness of the pressure pipes and the switching of the contact.
What does refurbished mean and what coverage does it have?: Part removed from a boiler out of service, inspected and tested. Includes 1-year warranty and 14-day return policy. Delivery within 2–4 working days in the EU.

Ariston Minimum Water Pressure Switch Microtec T2 LLS 23 MFFI Ref. 995903

Key Data

Ariston

Chaffoteaux

Related Spare Parts Boiler Pressure Switch Microtec T2 LLS 23 MFFI