Combi Boiler Spare Parts

Combi boiler spare parts: circulation pump, 3-way valve, plate heat exchanger, expansion vessel, gas valve, NTC sensor and safety relief valve. Yedepa stocks original and compatible boiler parts for Vaillant, ECA, Demirdöküm, Baymak and Bosch combi boilers; the compatible boiler models are listed on every product page.

Combi Boiler Spare Parts by Part Group

• Circulation pump: Boiler-type pumps, primarily Wilo and Grundfos, are listed by power (W) and connection size in the circulation pumps group.
• 3-way valve: If only the motor is to be replaced, see 3-way valve motors; if it is to be replaced together with its body, see 3-way valve assemblies; cartridge, seal and shaft sets are under repair kits.
• Plate heat exchanger: Plate heat exchangers selected by the number of plates and screw spacing; scaling of the heat exchanger on the hot water side is the most common reason for replacement.
• Expansion vessel: Boiler expansion vessels by litre capacity and connection size (3/8", 1/2").
• Gas valve: Honeywell and boiler-brand-specific gas valves.
• NTC sensor: Immersion and clip-on (surface) type NTC sensors.
• Ignition and ionisation electrodes: Single, double and ionisation-type ignition electrodes (spark plugs).
• Flue fan: Fime-motor and brand-compatible boiler flue fans.
• Turbine and pressure sensor: Turbines (flow sensors) that read the hot water flow, and water pressure sensors and switches are in this group; the air pressure switches (air pressostat, pressure switch) that monitor the flue draught are listed separately.
• Safety and filling: 3 bar safety relief valves, filling loop taps and pressure gauges.
• Consumables and condensate: gaskets, O-rings and diaphragms, and the siphon and drain parts of condensing boilers under condensate system parts.

Compatible Boiler Parts by Brand

• Vaillant: Gas valves, heat exchangers, pumps and sensors for the Ecotec, Turbotec and Atmotec series; for example the Vaillant Ecotec Pro 24/25/28 and Turbotec gas valve.
• ECA: The ECA 3-way valve repair kit for the Proteus, Confeo and Calora series, and the 3-way valve stepper motor used in ECA, Demirdöküm, Vaillant, Viessmann, Ferroli and Ariston boilers.
• Demirdöküm: The Zilmet 7 litre expansion vessel (3/8" connection) and the Aden immersion NTC sensor for the Neva, Atron and Aden series.
• Ariston, Bosch, Buderus and Ferroli: The 8 litre 3/8" expansion vessel and the Bosch, Buderus and Viessmann 14-plate heat exchanger.
• Baymak: The ignition electrode (compatible with ECA Premix Proteus, Baymak Novadens Extra, Ariston) and the 220 V 70 N 3-way valve stepper motor for the Novadens and Eco series.
• Viessmann: The Vitopend 100 12-plate heat exchanger for the Vitopend series.

Values to Check When Choosing the Right Part

1. Boiler model and series: Parts differ between series within the same brand; compare the full model name on the rating plate with the compatible model list on the product page.
2. Connection size: The 3/8" versus 1/2" distinction for expansion vessels, filling loop taps and safety relief valves; the number of plates and screw spacing (mm) for heat exchangers.
3. Electrical ratings: Voltage (V) and power (W) for pumps and flue fans; torque (N) and connector type for 3-way valve motors; resistance value and mounting type for NTC sensors.
4. Capacity: Litre capacity and pre-charge pressure for expansion vessels; the number of plates corresponding to the kW output for heat exchangers.

Fault Symptoms and Replacement Guides

If the boiler heats but gives no hot water, the 3-way valve; if the pressure keeps dropping, the expansion vessel or safety relief valve; if there is noise and fluctuating heating, the circulation pump are the first parts to check. To distinguish the symptoms and for step-by-step replacement, you can read our 3-way valve, expansion vessel, safety relief valve and circulation pump guides. We keep the parts that technicians and technical service companies replace frequently during the winter season together in the catalogue, and make it easy to match the right part for bulk requirements using the compatibility information on the product pages.