Description
This is a compact replacement synchronous motor intended as a spare for two-port and three-port spring‑return motorised valves used in domestic central‑heating installations. It is the drop‑in motor used to drive the small pinion that opens and closes zone and mid‑position valves: electrically it runs from a 220–240V AC, 50Hz supply and produces a slow, steady 4 RPM output at around 6W, which is what the original valve actuators need for reliable, repeatable movement.
Key specifications
- Supply: 220–240V AC, 50Hz
- Output: 4 RPM, approximately 6W
- Mounting: standard teardrop footprint with two fixing lugs
- Output shaft: pinion wheel style (for valve head engagement)
- Physical size: ~60 × 40 × 52 mm; weight ≈ 0.190 kg
- Manufacturer code / SKU: SYNABOXED
What it does and where it fits
The unit replaces the synchron (synchronous) motor inside a valve head. Those motors are simple, low‑speed synchronous types with a spring return: the motor rotates the valve spindle slowly to change flow paths, and when power is removed the valve’s internal spring returns it to the rest position. This motor is intended for the common teardrop‑footprint valve heads made by a number of heating manufacturers; the manufacturer lists compatibility with ACL, Drayton, Honeywell, Tower, Landis & Steafa and Satchwell valve bodies. Because it uses the industry standard mounting and pinion arrangement it will fit many legacy two‑port zone valves and three‑port mid‑position valves without modification.
Installation and compatibility considerations
Practical replacement is straightforward provided the replacement motor has the same mounting holes and pinion engagement as the unit being replaced. The motor’s teardrop footprint and two fixing lugs are the usual pattern for many UK valve heads, so in many cases you can swap the motor without changing the valve body. Before you fit, check the physical pinion diameter and tooth profile match the valve head — those mechanical details are the common reason a motor won’t engage correctly even when the footprint and electrical connections look right.
Electrically it is a mains‑voltage device, so the installer must isolate the boiler/zone wiring and ideally confirm the wiring colours and connections before disconnecting the old motor. The motor is intended for the usual 220–240V AC, 50Hz supply found on UK systems. If the valve head has auxiliary switches (used to signal ‘call for heat’ to a boiler) those are part of the valve body rather than the motor; fitting this motor will restore actuation but won’t add auxiliary switching where a valve body lacks it.
Performance and limitations
The motor’s slow 4 RPM speed and low power draw (≈6W) are deliberate: valve actuators need torque delivered slowly to move a sealed water valve reliably and to work with the internal spring return. This motor is not a high‑torque or high‑speed device and is not suitable for applications requiring fast actuation. It is a straightforward replacement rather than an upgrade.
Note that sellers sometimes list slightly different output figures for visually similar replacement motors (for example, alternative listings for the same SKU have shown 5 RPM/5 W). For this specific SYNABOXED variant the verified specification is 4 RPM at 6W; if an exact match to the original motor’s speed or power is critical to system behaviour, check the label on the motor you remove and confirm the product markings before ordering.
Practical notes for buyers and installers
- Safety first: this is a mains device. Work only with the supply isolated, and if you’re not confident with wiring, use a competent heating engineer or electrician.
- Confirm mechanical fit: compare the teardrop mounting holes, pinion shape and height with the old motor; small differences in pinion dimensions cause poor engagement or slippage.
- Check the valve body: spring‑return motors restore mechanical movement but won’t repair a seized valve spindle or worn internal gearbox — if the valve has been static for a long time, you may need to free or replace the valve assembly as well.
- Label check: when replacing, keep the old motor until you’ve confirmed the new unit works; the label and part code (SYNABOXED) are useful for future servicing.
Overall, this SYNABOXED unit is a practical spare for domestic central‑heating engineers and competent DIYers who need a dependable, low‑cost replacement for a worn or faulty valve head motor. Its standard mounting and conservative electrical rating make it suitable for restoring normal valve operation in many commonly used two‑ and three‑port valve designs; it is best treated as a like‑for‑like replacement rather than a retrofit improvement.
