✔ No Flue — Install Anywhere
With no combustion and no exhaust gases, the Astro V2 requires no flue penetration. It can be sited in kitchens, utility rooms, airing cupboards, garages, or any accessible location where the electrical supply can be run — ideal for listed buildings, flats without external walls available for flue, and properties where gas restrictions apply.
✔ Weather Compensation (V2)
The Fusion Astro V2 introduces weather compensation — the boiler automatically adjusts its output flow temperature based on external conditions, reducing energy consumption by up to 15% compared to fixed-temperature operation. This also reduces on/off cycling and extends the life of the heating elements.
✔ Built-in Programmer & LCD Display
The Astro V2 includes an integrated programmer and LCD control panel, removing the need for a separate external programmer. The display shows operating mode, flow temperature, system pressure, and active fault codes. External smart thermostat compatibility is also supported via the volt-free control input.
✔ 100% Efficient — ~100% of Input to Heat
All electrical input is converted directly to heat — there is no flue loss, no combustion inefficiency, and no standby heat loss from a hot water store (in combi mode). The ErP rating is D for heating and A for hot water. When powered from renewable electricity (solar PV, green tariff), the boiler operates with zero direct carbon emissions.
✔ Suitable for Radiators & Underfloor Heating
The Astro V2 supports heating flow temperatures from 30°C to 80°C, making it suitable for both conventional panel radiators (typically 60–80°C) and underfloor heating systems (typically 35–55°C). The adjustable output temperature allows the boiler to be correctly set for either application without modification.
✔ Advanced Diagnostics & WRAS Approved
The V2 incorporates integral system diagnostics that display fault codes directly on the LCD panel — reducing call-out time by enabling the installer to identify faults quickly. Internal RCD protection and a high-current thermal cut-out provide safety layers. WRAS approved for connection to the domestic water supply.
✔ 5-Year Warranty — Valve Kit Now Included
5-year warranty subject to conditions (registration required). The Astro V2 now comes with the straight valve kit included — 2× ¾" F × 22mm angled valves (CB153) for heating connections and 2× ½" F × 15mm angled valves (CB154) for DHW connections — previously sold separately. The optional Compliance Installation Pack adds programmer, thermostat, filter, inhibitor, and cleaner for a fully compliant one-box installation.
✔ Quiet — 32 dB(A) Operation
Rated at 32 dB(A) operating noise — comparable to a quiet library whisper — the Astro V2 is suitable for installation adjacent to bedrooms, living areas, and home offices without noise nuisance. No combustion roar, no flue fan, and no firing sequence. The ErP smart pump modulates for efficiency rather than running at full speed continuously.
Is it suitable as a direct replacement for a gas combi boiler?
Yes — the Astro V2 connects to the existing heating circuit using the same pipework configuration as a gas combi boiler (flow and return on ¾" connections, cold mains and hot water on ½"). No system redesign or radiator changes are required in most cases. The main work is the electrical supply upgrade. The boiler has no flue, so the existing flue opening can be sealed. The single-phase models are best suited to properties previously served by a 12–18kW gas combi; the 24kW three-phase model is suitable for larger properties currently served by a higher-output gas boiler.
What external thermostat controls are compatible?
The Astro V2 accepts a volt-free (potential-free) external control signal at its control terminals — compatible with any conventional wired room thermostat, and wireless thermostats with a wired relay receiver. Smart thermostats (Hive, Tado, Drayton Wiser) with volt-free outputs work correctly when wired to the external control input. Remove the link across the external control terminals before connecting any external control — leaving the link in place will cause the boiler to run continuously regardless of thermostat state. The built-in programmer can be used alongside or instead of an external programmer.
Can it be used with solar PV or off-peak electricity tariffs?
Yes — the Astro V2 is one of the most straightforward boilers to integrate with solar self-consumption and time-of-use tariffs (Octopus Go, Economy 7, Agile). The built-in programmer can schedule heating to run during cheap-rate or self-generated periods. For direct PV diversion, a solar diverter (such as a myenergi eddi) can be wired to the external control input. Weather compensation (V2 feature) further reduces consumption by modulating output to actual demand rather than firing at full power.
