Warmflow
The Warmflow Zeno_R290_User_Manual is a monobloc air-source heat pump featuring a 75 degree Celsius maximum flow temperature, a 4.92 SCOP, and a 5-year parts and labour warranty.
The Warmflow Zeno_R290_User_Manual (A-Series) is a high-temperature monobloc air-source heat pump designed for the UK domestic market. Utilizing R290 refrigerant with a Global Warming Potential of 3, it offers a technical solution for both new builds and retrofits. Available in 9kW, 15kW, and 22kW variants, the range provides flow temperatures up to 75°C, making it compatible with existing radiator systems while maintaining an A+++ ErP rating at 35°C flow temperatures.
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Full technical specifications extracted from the manufacturer brochure. Empty sections are hidden.
The Warmflow Zeno_R290_User_Manual range, encompassing the AS01, AS02, and AS03 models, utilizes natural refrigerant technology for domestic heating. As a monobloc system, the entire refrigeration circuit is hermetically sealed within the outdoor unit, which weighs 102kg and stands 795mm high. The use of R290 (propane) allows the appliance to achieve a maximum flow temperature of 75°C, which is significantly higher than traditional R32 systems. This capability is specifically intended for retrofit applications where existing heat emitters require higher temperatures during peak winter loads.
Efficiency is a core metric for this series. The 9kW AS01-R290 model achieves a SCOP of 4.92 at a 35°C flow temperature and 3.07 at 55°C, resulting in ErP ratings of A+++ and A++ respectively. With a nominal COP of 4.79 at A7/W35, the unit maintains high seasonal performance even in colder climates, with a minimum operating outdoor temperature of -25°C.
Installation requirements are defined by specific hydraulic and spatial constraints. The unit requires 28mm pipework and a minimum water flow rate of 10 litres per minute. A buffer tank is mandatory to ensure sufficient system volume for the reverse cycle defrost method. Clearance is critical for airflow; the manufacturer specifies 200mm behind the unit, 500mm at the sides, and 1500mm at the front.
Electrically, the Zeno_R290_User_Manual is a single-phase 230V appliance. It features a low startup current of just 1 Amp, though the 9kW variant requires a 20A MCB. Control is managed via a dedicated touchscreen controller or the Warmlink App using a DTU module. The system is Smart Grid ready and supports Modbus communication for integration with broader building management systems.
Maintenance is required at 12-month intervals to maintain the 5-year parts and labour warranty. Key service tasks include inspecting electrical connections with the power isolated, cleaning the heating circuit filter or strainer, and verifying the concentration of the system corrosion inhibitor. Diagnostic support is provided through an onboard controller that displays fault codes such as E032 for low flow errors or E11 for high-pressure protection in the refrigeration circuit. All installations must be registered with the manufacturer to validate the warranty period.
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/warmflow/as01-r290#fault-p01 to jump straight to the entry.
| Code | Meaning | Details |
|---|---|---|
| P01Lockout | Heating Return Temperature Sensor Error Show causes & actionsThe temperature sensor is faulty or disconnected. Likely causes
Engineer action Test the operation of the heating return temperature sensor and re-connect/replace if necessary. | Details |
| P02Lockout | Heating Flow Temperature Sensor Error Show causes & actionsThe temperature sensor is faulty or disconnected. Likely causes
Engineer action Test the operation of the heating flow temperature sensor and re-connect/replace if necessary. | Details |
| P03Lockout | DHW Cylinder Temperature Sensor Error Show causes & actionsThe temperature sensor is faulty or disconnected. Likely causes
Engineer action Test the operation of the DHW cylinder temperature sensor and re-connect/replace if necessary. | Details |
| E08Lockout | Communication Error Show causes & actionsThere is a communication error between the controller and the appliance. Likely causes
User action Check the wiring connections between the controller and the appliance. Engineer action Check the wiring and connections between the controller and the appliance. | Details |
| E11Lockout | High Pressure Protection Show causes & actionsThe high pressure switch in the refrigeration circuit has been tripped. Likely causes
Engineer action Check the operation of the high pressure switch and refrigeration circuit in terms of gas pressure. | Details |
| E032Lockout | Low Flow Error Show causes & actionsThere is not enough flow in the heating circuit. Likely causes
Engineer action Check the plumbing circuit for blockages or air, valves are open and the operation of the circulating pump. | Details |
Patterns that group across the manufacturer's fault-code table. Each entry links to the full code listing further down the page.
Engineer: Test the operation of the heating return temperature sensor and re-connect/replace if necessary.
Triggered by fault code P01.
Engineer: Test the operation of the heating flow temperature sensor and re-connect/replace if necessary.
Triggered by fault code P02.
Engineer: Test the operation of the DHW cylinder temperature sensor and re-connect/replace if necessary.
Triggered by fault code P03.
Common questions from engineers and homeowners about the Warmflow AS01-R290.
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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 30 April 2026.
User: Check the wiring connections between the controller and the appliance.
Engineer: Check the wiring and connections between the controller and the appliance.
Triggered by fault code E08.
Engineer: Check the operation of the high pressure switch and refrigeration circuit in terms of gas pressure.
Triggered by fault code E11.