The Spirotech SpiroTrap MB3 (UE022WJ) is a 22mm brass magnetic dirt separator
designed for closed central heating and cooling systems. Using a full-flow settling
principle combined with an external neodymium magnet, it continuously strips
particles from 5 μm — including magnetite — from circulating system water.
Independent research confirms that pairing an MB3 with a SpiroVent RV2 deaerator can reduce
gas consumption by up to 13%.
5 μm
Min particle removal
Kvs 9.07
Flow coefficient
INSTALLER NOTE — SYSTEM POSITION
Install on the return pipe, at the point where system water re-enters the boiler or heat source. The unit must be installed vertically with the socket pointing downward to allow gravity-assisted dirt collection. Ensure the drain valve is always accessible for annual servicing.
CLOSED SYSTEMS ONLY
The SpiroTrap MB3 is not suitable for open-vented systems, solar circuits, or mains-pressure domestic hot water. Maximum glycol concentration is 50% v/v ethylene glycol. For solar applications, see dedicated SpiroVent Solar products.
SAVE UP TO 13% ON GAS
Independent research commissioned by Spirotech demonstrated that a SpiroTrap MB3 + SpiroVent RV2 combination reduces gas consumption by up to 13% in standard residential central heating systems. The saving comes from eliminating corrosion by-products that impede heat-exchanger efficiency over time.
Full-Flow Settling Principle
Unlike cartridge filters that restrict flow, the MB3 widens the flow path internally, reducing velocity and causing particles to settle into the collection chamber. No bypass, no isolating valves, no disposable filter element — consistent low pressure drop at all flow rates.
External Neodymium Magnet
The slide-off magnetic jacket concentrates flux inside the collection chamber, capturing even sub-5 μm magnetite particles. Maintenance takes seconds: remove the jacket, open the drain valve, collected sludge purges under system pressure — no system shutdown required.
Universal Compression Connection
The 22mm compression coupling accepts standard 22mm copper or plastic pipe. The swivel design allows the drain valve to be oriented in any direction post-installation, so the pipe arrangement doesn't dictate access.
SpiroLIFE 20-Year Guarantee
Spirotech backs all brass SpiroTrap MB3 units with a 20-year SpiroLIFE warranty when operating below 110 °C — a direct reflection of the all-brass construction and the absence of replaceable internal components that could degrade.
Technical Specification — SpiroTrap MB3 22mm (UE022WJ)
| Connection & Hydraulics |
|---|
| Article Number |
UE022WJ |
| Product Type |
SpiroTrap MB3 — 22mm — Magnet — 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 |
| Magnet Type |
Neodymium (external jacket) |
| Separator Principle |
Full-flow with settling |
| Filter Volume |
0.36 litres |
| Construction Length |
92 mm |
| With Drain Tap |
Yes |
| Auto De-aerator Included |
No |
| Compliance & Warranty |
|---|
| Design Standard |
EN 13445 |
| CE Marking |
2014/68/EU (Pressure Equipment Directive) |
| Warranty |
20 years — SpiroLIFE |
Frequently Asked Questions
Where should the SpiroTrap MB3 22mm be installed?
On the return pipework, immediately before the boiler or heat pump inlet. At this point, cooler, denser water carries sludge and magnetite back from the system — positioning the MB3 here intercepts the dirt before it reaches heat exchanger surfaces, pumps, and zone valves.
How often does the MB3 need servicing?
Spirotech recommends draining the collection chamber once a year as a minimum. The procedure requires no tools and takes under two minutes: slide off the magnet sleeve, open the drain valve briefly, allow system pressure to expel collected debris into a bucket, then close and replace the magnet. The system does not need to be shut down.
Is the UE022WJ suitable for heat pump systems?
Yes. Spirotech publishes a dedicated Heat Pump Installation Diagram for MB3 / RV2. The MB3 is typically installed on the return side of the heat pump indoor unit. For systems requiring hydraulic separation between a heat pump primary loop and a secondary distribution loop, the SpiroCross AX-J (AX100J / AX125J) is the appropriate product — it combines the dirt and air separation of the MB3/RV2 with full hydraulic balancing in a single unit.
What is the difference between the MB3, MBC1, and MBL?
All three use a neodymium magnet and the same full-flow settling principle. The MB3 is the standard product with compression connections from 22mm to 2". The MBC1 Micro is a more compact, cost-effective variant for 22mm only, with a 10-year rather than 20-year warranty. The MBL (UE125WJ) is the Large version with a magnetic field booster for higher-flow threaded-connection installations from Rp 1¼" upward.
Can the MB3 be used with underfloor heating systems containing antifreeze?
Yes, up to 50% ethylene glycol / water by volume. This covers the antifreeze concentrations used in most residential and light-commercial underfloor heating and heat pump systems in the UK. Do not use with propylene glycol concentrations above manufacturer limits or in open-vented systems.
