The Spirotech SpiroVent RV2 (UA022W) is a 22mm brass microbubble air deaerator
for closed central heating and cooling systems. Unlike automatic air vents that only expel
free air pockets at the vent point, the SpiroVent RV2 uses a patented SpiroTube coalescing
element to collect and continuously remove dissolved microbubbles from the entire
circulating system — the cause of noise, cold spots, and corrosion that ordinary bleeding cannot eliminate.
Independent research confirms that a SpiroVent RV2 paired with a SpiroTrap MB3 can reduce
gas consumption by up to 13% in residential heating systems.
Microbubble
Removal grade
Kvs 9.07
Flow coefficient
INSTALLER NOTE — POSITION AT HOTTEST POINT
The SpiroVent RV2 must be installed at the hottest point in the system — the flow pipe immediately leaving the boiler or heat pump. At this location, water temperature is highest and solubility of dissolved gases lowest, so microbubbles nucleate and are most easily captured. Installing it downstream on cooler pipework significantly reduces effectiveness.
AIR DEAERATOR ONLY — PAIR WITH SPIROTRAP FOR FULL PROTECTION
The SpiroVent RV2 removes air and microbubbles only — it does not collect dirt, magnetite, or sludge. For complete system water quality, pair the UA022W with the SpiroTrap MB3 UE022WJ on the return pipework. This two-product combination addresses both root causes of central heating degradation in a single, cost-effective installation.
WHY STANDARD BLEEDING IS NOT ENOUGH
Traditional automatic air vents remove free air only at the point of installation. Dissolved microbubbles — gases held in solution that come out of solution as water heats and cools — are invisible, flow throughout the system, and cannot be removed by bleeding. Over time, they form the oxygen-rich environment that drives iron oxide (magnetite) formation and reduces circulating pump efficiency.
SpiroTube Coalescing Technology
The internal SpiroTube element creates a low-velocity coalescing zone where microbubbles merge into larger bubbles, rise to the integral air release valve, and are automatically expelled. The process is continuous and fully passive — no sensors, no electronics, no maintenance of the collection element.
High-Quality Leak-Proof Air Valve
The solid valve seat construction ensures the automatic air release valve closes reliably when system pressure is present, preventing water ingress. This is a known weak point on cheaper deaerators — the Spirotech valve design is why the unit carries a 20-year SpiroLIFE warranty.
No System Shutdown for Servicing
Like the SpiroTrap MB3, the SpiroVent RV2 requires no system isolation or depressurisation to service. The automatic air release valve handles discharge continuously. If a manual inspection of the SpiroTube element is required, it can be unscrewed with the system pressurised in service.
Glycol-Compatible Design
Rated to 50% v/v ethylene glycol, the UA022W is fully suitable for heat pump primary circuits, underfloor heating systems with antifreeze, and commercial cooling applications. The Viton-sealed valve tolerates the chemical environment of glycol solutions without degradation.
Technical Specification — SpiroVent RV2 22mm (UA022W)
| Connection & Hydraulics |
|---|
| Article Number |
UA022W |
| Product Type |
SpiroVent RV2 — 22mm — Universal Connection |
| Connection |
22mm compression ring (with couplers) |
| Flow Direction |
Variable (reversible) |
| Max Flow Rate |
1.3 m³/h |
| Kvs Value |
9.07 m³/h |
| Inlet/Outlet Offset |
0 mm (in-line) |
| Operating Limits |
|---|
| Max Operating Pressure |
10 bar (PN 10) |
| Temperature Range |
0 – 110 °C (continuous) |
| Max Glycol (Ethylene) |
50% v/v |
| Suitable for Heating |
Yes |
| Suitable for Cooling |
Yes |
| Closed System |
Yes |
| Open System |
No |
| Solar Applications |
No |
| Physical & Construction |
|---|
| Housing Material |
Brass |
| Separator Type |
Air (microbubble deaeration) |
| Auto De-aerator |
Yes — integral automatic air release valve |
| Magnet |
No |
| Filter Volume |
0.18 litres |
| Construction Length |
112 mm |
| With Drain Tap |
No |
| Compliance & Warranty |
|---|
| Design Standard |
EN 13445 |
| CE Marking |
2014/68/EU (Pressure Equipment Directive) |
| Warranty |
20 years — SpiroLIFE |
Frequently Asked Questions
What is the difference between a SpiroVent and a standard automatic air vent (AAV)?
A standard AAV removes only free air at one specific location and is passive until a sizeable air pocket reaches the vent. The SpiroVent RV2 uses a SpiroTube coalescing element to attract and coalesce dissolved microbubbles from the entire circulating volume. This removes the invisible dissolved gas phase that AAVs cannot address — the phase responsible for ongoing oxygen-driven corrosion.
Does the SpiroVent RV2 replace the boiler's built-in air vent?
No — the boiler's own air vent should remain in place. The SpiroVent RV2 should be installed on the system flow pipework, typically 150–300mm downstream from the boiler outlet, where it deaerates the entire circulating volume. The boiler vent handles local gas pockets; the RV2 handles system-wide dissolved gas over the long term.
Is the UA022W suitable for underfloor heating systems?
Yes. Position the SpiroVent RV2 at the manifold flow header, which represents the hottest point in an underfloor heating primary distribution circuit. This is particularly important in heat pump underfloor systems where lower flow temperatures mean dissolved gas is released more slowly but equally damaging to pump efficiency over time.
Does the unit need annual servicing?
The SpiroVent RV2 is largely maintenance-free. The internal SpiroTube element does not need routine replacement. Spirotech recommends a visual check of the air release valve annually — confirm it is not weeping water (indicating valve seat wear) and that the top cap is clean and unblocked. If the system has been treated with inhibitor chemicals, confirm they are compatible with the brass housing.
What happens if the SpiroVent is installed on the return instead of the flow?
Installing on the cooler return pipework significantly reduces effectiveness. At lower temperatures, more gas remains dissolved and is not released at the coalescing surface. The unit will still provide some benefit, but performance will be well below the rated 13% gas saving figure. Always prioritise the flow pipe at the hottest point.
