Daikin
The Daikin Altherma 4 H R290 high-temp integrated indoor EPVX (R290) is a split air-source heat pump, available in 10 kW and 14 kW variants, using R290 refrigerant.
The Daikin Altherma 4 H R290 high-temp integrated indoor EPVX (R290) is a split air-source heat pump designed for domestic heating applications in the UK. This appliance utilises R290 refrigerant, a low GWP option, and is available in various configurations, including 10 kW and 14 kW output models. This page provides essential technical information for gas and heating engineers, covering model variants, operational notes, and common fault codes to aid in installation, servicing, and troubleshooting.
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Full technical specifications extracted from the manufacturer brochure. Empty sections are hidden.
The Daikin Altherma 4 H F+W series represents a range of split air-source heat pumps, featuring R290 refrigerant with a Global Warming Potential (GWP) of 3. This low GWP refrigerant aligns with environmental objectives for domestic heating systems. The product family includes models such as the EPVX10S(U)18A4V and EPVX14S(U)18A4V, indicating 10 kW and 14 kW nominal capacities respectively, along with different electrical configurations.
The indoor unit integrates with the heating system, offering compatibility with the ONECTA app and Daikin room thermostats for comprehensive control. Built-in WiFi and smart grid readiness enhance system flexibility and remote management capabilities. Weather compensation is a standard feature, optimising performance based on external conditions. Fault codes are provided to assist engineers in diagnosing operational issues efficiently.
Every fault code listed in the manufacturer brochure, with likely causes and engineer actions. Each code has a permalink — paste a URL like https://www.boilertag.com/heat-pumps/daikin/altherma-4-h-r290-high-temp-integrated-indoor-epvx-r290#fault-f1 to jump straight to the entry.
| Code | Meaning | Details |
|---|---|---|
| f1 | An error occurred. Show causes & actionsUser action See '8.1 To display the help text in case of a malfunction' [► 16] for more information. | Details |
| f2 | A malfunction occurred. Show causes & actionsUser action See '8.1 To display the help text in case of a malfunction' [► 16] for more information. | Details |
| Desired room temperature too low (high) | You are feeling too cold (hot) in your living room Show causes & actionsThe desired room temperature is too low (high). User action Increase (decrease) the desired room temperature. See '5.6.2 To change the desired room temperature' [11]. | Details |
| Desired room temperature cannot be reached | You are feeling too cold (hot) in your living room Show causes & actionsThe desired room temperature cannot be reached. User action If the problem recurs daily, do one of the following: • Increase (decrease) the room temperature preset value. See the user reference guide. • Adjust the room temperature schedule. See '5.8 Schedule screen: Example' [► 13]. | Details |
| Weather-dependent curve set incorrectly | You are feeling too cold (hot) in your living room Show causes & actionsThe weather-dependent curve is set incorrectly. User action Adjust the weather-dependent curve. See '5.9 Weather-dependent curve' [► 14]. | Details |
| Unusually high DHW consumption | The water at the tap is too cold Show causes & actionsYou ran out of domestic hot water because of unusually high consumption. User action If you immediately need domestic hot water, activate: • [4.1] Powerful operation. However, this consumes extra energy. See '5.7.4 Using DHW powerful operation' [► 12]. • [4.3] Manual tank heat-up. | Details |
| Desired DHW tank temperature too low | The water at the tap is too cold Show causes & actionsThe desired DHW tank temperature is too low. User action If the problems recur daily, do one of the following: • Increase the DHW tank temperature preset value. See the user reference guide. • Adjust the DHW tank temperature schedule. Example: Program to additionally heat up the DHW tank to a preset value (Eco setpoint = lower tank temperature) during the day. See '5.8 Schedule screen: Example' [► 13]. | Details |
| Heat pump damaged | Heat pump failure Show causes & actionsHeat pump is damaged. User action See '8.1 To display the help text in case of a malfunction' [► 16]. Engineer action When the heat pump fails to operate, the backup heater and/or booster heater can serve as an emergency heater. It then takes over the heat load either automatically or by manual interaction. • When Emergency is set to Automatic and a heat pump failure occurs: • For ETVH/X: The backup heater automatically takes over the domestic hot water production and space heating. • For ETBH/X: The backup heater automatically takes over the heat load, and the booster heater in the optional tank takes over the domestic hot water production. • When Emergency is set to Manual and a heat pump failure occurs, the domestic hot water heating and space heating stops. To manually recover it via the user interface, go to the Malfunctioning main menu screen and confirm whether the backup heater and/or booster heater can take over the heat load or not. Alternatively, when Emergency is set to: • auto SH reduced/DHW on, space heating is reduced but domestic hot water is still available. • auto SH reduced/DHW off, space heating is reduced and domestic hot water is NOT available. • auto SH normal/DHW off, space heating operates as normally but domestic hot water is NOT available. Similarly as in Manual mode, the unit can take the full load with the backup heater and/or booster heater if the user activates this via the Malfunctioning main menu screen. When the heat pump fails, 4 or ▲ will appear on the user interface. | Details |
| Air in the system | The system is making gurgling noises after commissioning Show causes & actionsThere is air in the system. Engineer action Purge air from the system. (a) (a) We recommend to purge air with the air purge function of the unit (to be performed by the installer). If you purge air from the heat emitters or collectors, mind the following: WARNING Air purging heat emitters or collectors. Before you purge air from heat emitters or collectors, check if 4 or ▲ is displayed on the home screen of the user interface. • If not, you can purge air immediately. • If yes, make sure that the room where you want to purge air is sufficiently ventilated. Reason: In case of a breakdown, refrigerant might leak into the water circuit, and subsequently into the room when you purge air from the heat emitters or collectors. | Details |
| Incorrect hydraulic balance | The system is making gurgling noises after commissioning Show causes & actionsIncorrect hydraulic balance. Engineer action 1. Perform hydraulic balancing to assure that the flow is correctly distributed between the emitters. 2. If hydraulic balancing is not sufficient, it is recommended to increase the Delta T heating ([1.14] / [2.14]) value. | Details |
| Various malfunctions | The system is making gurgling noises after commissioning Show causes & actionsVarious malfunctions. User action Check if 4 or ▲ is displayed on the home screen of the user interface. See '8.1 To display the help text in case of a malfunction' [► 16] for more information about the malfunction. | Details |
Patterns that group across the manufacturer's fault-code table. Each entry links to the full code listing further down the page.
User: See '8.1 To display the help text in case of a malfunction' [► 16] for more information.
Triggered by fault code f1.
User: See '8.1 To display the help text in case of a malfunction' [► 16] for more information.
Triggered by fault code f2.
User: Increase (decrease) the desired room temperature. See '5.6.2 To change the desired room temperature' [11].
Triggered by fault code Desired room temperature too low (high).
User: If you immediately need domestic hot water, activate: • [4.1] Powerful operation. However, this consumes extra energy. See '5.7.4 Using DHW powerful operation' [► 12]. • [4.3] Manual tank heat-up.
Triggered by fault code Unusually high DHW consumption.
User: See '8.1 To display the help text in case of a malfunction' [► 16].
Engineer: When the heat pump fails to operate, the backup heater and/or booster heater can serve as an emergency heater. It then takes over the heat load either automatically or by manual interaction. • When Emergency is set to Automatic and a heat pump failure occurs: • For ETVH/X: The backup heater automatically takes over the domestic hot water production and space heating. • For ETBH/X: The backup heater automatically takes over the heat load, and the booster heater in the optional tank takes over the domestic hot water production. • When Emergency is set to Manual and a heat pump failure occurs, the domestic hot water heating and space heating stops. To manually recover it via the user interface, go to the Malfunctioning main menu screen and confirm whether the backup heater and/or booster heater can take over the heat load or not. Alternatively, when Emergency is set to: • auto SH reduced/DHW on, space heating is reduced but domestic hot water is still available. • auto SH reduced/DHW off, space heating is reduced and domestic hot water is NOT available. • auto SH normal/DHW off, space heating operates as normally but domestic hot water is NOT available. Similarly as in Manual mode, the unit can take the full load with the backup heater and/or booster heater if the user activates this via the Malfunctioning main menu screen. When the heat pump fails, 4 or ▲ will appear on the user interface.
Triggered by fault code Heat pump damaged.
Common questions from engineers and homeowners about the Daikin Altherma 4 H F+W.
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Specifications on this page are extracted from the manufacturer brochure. Always cross-check against the latest datasheet before commissioning or quoting. Last updated 28 June 2026.