The Spirotech SpiroVent RV2 28mm (UA028W) delivers continuous microbubble
air deaeration for 28mm closed heating and cooling circuits. Sharing the same
SpiroTube coalescing technology as its 22mm counterpart, it handles the higher flow rates
found in larger boiler systems, multi-zone underfloor heating, and commercial cooling circuits.
Its Kvs 10.13 ensures the unit introduces no meaningful restriction even at the
upper end of its 2.0 m³/h design flow, while the integral automatic air release valve
continuously expels accumulated gas without manual intervention.
Microbubble
Removal grade
Kvs 10.13
Flow coefficient
INSTALLER NOTE — FLOW PIPE PRIORITY
Install on the system flow pipe at the highest temperature point — this maximises gas nucleation and coalescing efficiency. On 28mm systems with multiple circuits, install the SpiroVent RV2 on the primary flow before the manifold so it deaerates the entire secondary volume. Ensure the unit is easily accessible for the annual visual valve check.
28mm SYSTEM — PAIR WITH UE028WJ SPIROTRAP MB3
The SpiroVent RV2 UA028W removes dissolved air and microbubbles; it does not capture dirt or magnetite. For complete system water quality protection, pair with the SpiroTrap MB3 28mm (UE028WJ) on the return pipework. Both units share the same connection size, Kvs band, and SpiroLIFE 20-year warranty.
HIGHER CAPACITY — SAME PROVEN TECHNOLOGY
The UA028W shares the identical SpiroTube operating principle with the UA022W — the only engineering differences are the larger 28mm compression connection and the higher Kvs (10.13 vs 9.07). This means the same deaeration effectiveness, the same leak-proof valve quality, and the same 20-year SpiroLIFE guarantee.
Continuous Passive Deaeration
The SpiroTube element continuously coalesces dissolved microbubbles into larger bubbles as system water circulates. No sensors, timers, or electrical components — passive operation for 20+ years with no consumable elements to replace.
Integral Leak-Proof Air Valve
Spirotech's solid-seat valve construction reliably closes under system pressure once air has been expelled, preventing water drip. This valve quality is a core reason the product qualifies for the 20-year SpiroLIFE warranty — it does not degrade in the way plastic-ball float valves do over time.
Reversible Flow Connections
Flow may enter from either side, giving installers full freedom on pipework routing. The 28mm compression couplers accept standard copper or plastic pipe directly — no additional adaptors required for most 28mm system configurations.
Glycol-Ready Construction
Rated to 50% v/v ethylene glycol, the UA028W is fully compatible with heat pump primary circuits, underfloor heating antifreeze blends, and chilled water cooling systems where glycol is used for frost protection in cooler months.
Technical Specification — SpiroVent RV2 28mm (UA028W)
| Connection & Hydraulics |
|---|
| Article Number |
UA028W |
| Product Type |
SpiroVent RV2 — 28mm — Universal Connection |
| Connection |
28mm compression ring (with couplers) |
| Flow Direction |
Variable (reversible) |
| Max Flow Rate |
2.0 m³/h |
| Kvs Value |
10.13 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
Why do 28mm systems need a larger deaerator rather than two 22mm units?
Two 22mm units would each handle only part of the flow, creating turbulence at the tees and significantly reducing deaeration efficiency. The 28mm RV2 is sized to handle the full flow rate in a single unit, which is the correct approach for clean, low-pressure-drop deaeration. Never split a 28mm flow into two 22mm SpiroVents.
At what system size should I step up from 22mm to 28mm?
Generally, when the main distribution pipework is 28mm or when system flow exceeds 1.3 m³/h. This typically corresponds to boilers above approximately 25–30 kW output on a standard Δt of 20 K, or any multi-zone system where the primary pump is sized for 28mm pipe velocity.
Does the SpiroVent RV2 UA028W also remove magnetite?
No. The SpiroVent RV2 is an air deaerator only — it has no magnet and does not retain solid particles. For magnetite and sludge removal, fit the SpiroTrap MB3 28mm (UE028WJ) on the return pipework. The combination of both units on a 28mm system provides comprehensive system water quality protection.
Is the UA028W suitable for ground-source heat pump primary circuits?
Yes. Ground-source heat pump primary circuits typically use 28mm or 32mm pipework with glycol antifreeze. The UA028W is rated for 50% ethylene glycol and 10 bar, covering all standard GSHP primary circuit conditions. Install on the warmest point of the primary loop — the brine outlet from the heat pump evaporator before it returns to the ground array.
Does the UA028W need any commissioning after installation?
No active commissioning is required. The unit begins deaerating as soon as the system is pressurised and circulating. Spirotech recommends confirming the air release valve is free and not capped before commissioning, and that the system inhibitor is compatible with brass materials. An initial high-deaeration phase is normal in the first few weeks of operation as accumulated dissolved gas is purged.
