The Panasonic PAW-A2W-AFVLV is the genuine anti-freeze valve for Panasonic Aquarea monobloc heat pumps. Fitted to exposed external pipework, it opens automatically at 3°C and closes at 4°C, bleeding a small amount of system water to prevent the primary circuit from freezing during cold snaps. A durable brass-bodied valve with a simple 1/4" connection, it's a small, inexpensive component that protects the rest of the installation from a genuinely costly failure mode.
10 bar
Max operating pressure
-30 to 60°C
Ambient rating
×2 per unit
Typical quantity
Two valves per outdoor unit — unless glycol is specified
Panasonic's own installation documentation calls for two anti-freeze valves per outdoor unit (one on flow, one on return) on monobloc installs that don't use glycol antifreeze in the primary circuit. If your system uses a glycol-dosed primary, confirm with your system designer whether these valves are still required.
Genuine Panasonic part
Using the manufacturer-specified PAW-A2W-AFVLV (rather than a generic anti-freeze valve) keeps the installation aligned with Panasonic's own documentation and warranty expectations — the valve's opening and closing temperatures are matched to Aquarea's frost-protection strategy.
Key features
Automatic frost protection
Opens at 3°C to bleed a small volume of system water and relieve pressure, then closes again at 4°C once the risk has passed — fully automatic, no power or control signal required.
Durable brass housing
Brass body construction for long service life in an outdoor, weather-exposed location — built to withstand repeated freeze-thaw cycling over the life of the system.
Wide ambient operating range
Rated for ambient temperatures from -30°C to 60°C, with a valve operating temperature range of 0–65°C — suited to the full range of UK outdoor conditions.
Simple 1/4" connection
Straightforward 1/4" fitting integrates easily into existing monobloc pipework without specialist tooling.
Rated to 10 bar
Maximum operating pressure of 10 bar covers standard domestic and light commercial heat pump primary circuits with headroom to spare.
Designed for R290 monobloc systems
Specified by Panasonic for use with the WH-MDC and WH-MXC Aquarea monobloc series — matched to the frost-protection needs of an outdoor-mounted refrigerant circuit.
Technical specification
| Model code |
PAW-A2W-AFVLV |
| Function |
Automatic anti-freeze relief valve for exposed primary pipework |
| Opening temperature |
3°C |
| Closing temperature |
4°C |
| Body material |
Brass |
| Connection size |
1/4" |
| Maximum operating pressure |
10 bar |
| Valve operating temperature range |
0–65°C |
| Ambient temperature rating |
-30°C to 60°C |
| Typical quantity per outdoor unit |
2 (unless glycol antifreeze is specified in the primary circuit) |
| Compatible systems |
Panasonic Aquarea monobloc range, including WH-MDC and WH-MXC series |
What's in the box
- 1 × Panasonic PAW-A2W-AFVLV anti-freeze valve
- Manufacturer fitting instructions
Related accessories (sold separately)
- Second PAW-A2W-AFVLV valve — most monobloc installs require a pair (flow and return)
- PAW-TS1 or PAW-TS2 cylinder sensor (6 m or 20 m lengths)
- PAW-3WYVLV-HW 3-port valve for DHW tank installations
Frequently Asked Questions
Do I need one valve or two?
Panasonic's own design documentation specifies two anti-freeze valves per outdoor unit on standard monobloc installs — one on the flow pipe, one on the return. This listing is for a single valve, so order two unless your system uses glycol antifreeze in the primary circuit, in which case confirm requirements with your installer or system designer.
Where is the valve fitted?
On the exposed external pipework between the outdoor unit and the point where the primary circuit enters the building — the section most at risk of freezing in cold weather.
Does the valve need power or a control signal?
No — it's a fully automatic mechanical valve. It opens at 3°C and closes at 4°C purely from the water temperature at the valve body, with no electrical connection required.
Is this valve required if I'm using glycol antifreeze?
Not necessarily. Anti-freeze valves are primarily specified for systems without glycol dosing in the primary circuit. If your installer has specified glycol, confirm with them whether these valves still form part of your system design.
Will fitting this valve affect my system pressure?
In normal operation, no — the valve only opens briefly during a genuine frost risk to bleed a small amount of water and relieve pressure locally. Routine system pressure should be topped up as part of normal maintenance if the valve has operated.
