The Spirotech SpiroTrap MBL (UE125WJ) is the large-format, high-flow magnetic dirt
separator in the Spirotech brass range. Connecting via a Rp 1¼" BSP internal
thread, it is designed for commercial plant rooms, high-output boiler installations,
and multi-zone heating systems where 22mm or 28mm compression products are undersized.
Its magnetic field booster technology concentrates the neodymium magnetic field more
intensely than the standard MB3, ensuring unrivalled fast and optimal magnetite capture
even at the elevated flow rates that larger systems demand.
5 μm
Min particle removal
INSTALLER NOTE — THREADED CONNECTION
The UE125WJ uses a Rp 1¼" BSP internal thread — this is not a compression fitting. Use PTFE tape or approved thread sealant on mating male threads. Install vertically with the drain valve socket facing downward. The unit weighs 3.6 kg dry — ensure pipework is adequately supported and bracketed independently of the separator body.
MBL vs MB3 — WHEN TO USE THE LARGE VERSION
The MBL is engineered for systems where flow rates exceed the MB3's 2.0 m³/h limit but are within 3.6 m³/h. The magnetic field booster technology provides stronger magnetite separation at higher velocities. For systems above 3.6 m³/h, consult Spirotech's steel product range or the SpiroSelect sizing tool.
MAGNETIC FIELD BOOSTER TECHNOLOGY
Unlike the standard MB3, the MBL uses patented magnetic field booster technology that focuses the neodymium magnet's flux deep into the collection chamber. This means that even at the higher flow velocities present in large residential or commercial systems, magnetite and magnetic particles are pulled from the flow stream before they can pass through.
Magnetic Field Booster
The MBL's internal geometry channels the neodymium magnet field into the settling zone, not just at the wall of the collector. This deeper penetration captures fine magnetite that would escape a conventional magnetic sleeve at the same flow rate — critical for protecting boiler heat exchangers and pump impellers in high-output systems.
BSP Threaded Connections
The Rp 1¼" internal thread suits the larger pipework gauges common in commercial boiler plantrooms, primary circuits, and older properties with large-bore steel pipework. Compatible with standard BSP fittings and adaptors — no special tooling required.
On-Load Drain
Collected debris is expelled under system pressure — no need to isolate, depressurise, or drain the system. The drain tap accepts a standard 15mm hose tail for directed waste disposal. Spirotech recommends annual draining; high-debris environments may warrant quarterly checks.
High-Flow Hydraulics
With a max flow of 3.6 m³/h, the MBL covers the output of most domestic and light-commercial boilers rated up to approximately 50–70 kW on a standard Δt. The constant low pressure drop design avoids the marginal pump head that filter-type devices consume.
Technical Specification — SpiroTrap MBL Rp 1¼" (UE125WJ)
| Connection & Hydraulics |
|---|
| Article Number |
UE125WJ |
| Product Type |
SpiroTrap MBL — Rp 1¼" — Magnet — Universal Connection |
| Connection |
Rp 1¼" BSP internal thread (swivel) |
| Max Flow Rate |
3.6 m³/h |
| Max Flow Velocity |
1 m/s |
| Operating Limits |
|---|
| Max Operating Pressure |
10 bar (PN 10) |
| Temperature Range |
0 – 110 °C (continuous) |
| Max Glycol (Ethylene) |
50% v/v |
| Design Standard |
EN 13445 |
| Suitable for Heating |
Yes |
| Suitable for Cooling |
Yes |
| Closed Systems Only |
Yes |
| Physical & Construction |
|---|
| Housing Material |
Brass |
| Swivel Material |
Brass |
| Spirotube Tube |
Copper |
| Spirotube Wire |
Copper |
| Magnet Type |
Neodymium — Magnetic Field Booster Technology |
| Volume |
0.75 litres |
| Dry Weight |
3.6 kg |
| Dimensions (mm) |
|---|
| Height — vertical (Hv) |
224 mm |
| Height — horizontal (Hh) |
210 mm |
| Body Height (h) |
160 mm |
| Body Width (B) |
163 mm |
| Body Depth (b) |
138 mm |
| Pipe Length (L) |
128 mm |
| Body Diameter (D) |
84 mm |
| Air Vent Connection (e) |
G 3/4" |
| Compliance & Warranty |
|---|
| CE Marking |
2014/68/EU (Pressure Equipment Directive) |
| Warranty |
20 years — SpiroLIFE |
Frequently Asked Questions
Why choose the MBL over the MB3 for a 1¼" connection?
The MBL is not simply a larger MB3 — it incorporates magnetic field booster technology that increases magnetic flux density inside the collection chamber. At the flow rates seen in 1¼" pipework, this additional magnetic force is necessary to capture fine magnetite before it passes through the separator. The MB3 range goes up to Rp 2" but is designed for lower-velocity applications.
How does Rp 1¼" correspond to metric pipe sizes?
Rp 1¼" is British Standard Pipe Taper (BSP) equivalent to approximately 32mm nominal bore. It is the standard thread used on 32mm steel or copper commercial pipework. The external pipe diameter of mating fittings will be approximately 42mm (1½" OD tube).
Can the MBL handle glycol circuits for heat pumps?
Yes. The MBL is rated for up to 50% v/v ethylene glycol, covering all typical antifreeze concentrations in heat pump ground-loop and outdoor unit circuits. For heat pump systems also requiring hydraulic separation between primary and secondary loops, consider the SpiroCross AX125J as an alternative single-unit solution.
What G 3/4" connection is the air vent port for?
The air vent connection on the top of the MBL (labelled 'e' at G 3/4") is a manual bleed / flushing port, not an automatic deaerator. For automatic microbubble removal, install a separate SpiroVent RV2 on the flow side of the system. The port can also accept the SpiroPlus flush connector for system power-flushing.
Is annual servicing still sufficient for commercial use?
For high-usage commercial systems or new installations with significant initial debris (new build corrosion products, construction sediment), Spirotech recommends an inspection at 3 months and then 6 months after commissioning. Once debris has stabilised, an annual drain is usually adequate.
