MK WATER SIGNAL indicators provide a compact visual check of water movement. A ball or float moves inside a transparent tube. This family indicates flow presence rather than a numerical flow reading: its published standard minimum and maximum flow values are selection data, not a statement of measuring accuracy.
Construction and operating specifications
| Parameter | Specification |
|---|---|
| Fluid | Water |
| Maximum temperature | 80°C |
| Pressure resistance | 1 MPa |
| Mounting orientation | Upward, downward or sideways; observe the intended flow direction |
| Transparent tube | Acrylic |
| Fittings | C3604 brass |
| Spring | SUS304 |
| Ball | Nylon 66; a cylindrical float may be used depending on specification |
| O-ring | Nitrile rubber, standard version |
| Standard connection | Rc female; R male or mixed arrangements on request |
| SUS fitting option | Available on request |
Flow presence and model selection
Observe the ball or float to confirm that water is moving through the transparent tube. The standard-flow figures below describe the listed model selection, while the product description does not provide a quantitative flow-reading function. Do not interpret ball displacement as a calibrated L/min reading or infer a measuring accuracy that is not specified. Select a model whose standard-flow interval matches the intended water circuit, and define a separate measurement or alarm device where numerical readings or automatic detection are required.
Complete water-model dimensions and flow data
| Model | Port | Length (mm) | Width (mm) | Standard minimum flow (L/min) | Standard maximum flow (L/min) |
|---|---|---|---|---|---|
| MK15-1TW | Rc1/8 | 50 | 15 | 0.1 | 1 |
| MK25-1TW | Rc1/8 | 68 | 25 | 0.6 | 6 |
| MK25-2TW | Rc1/4 | 68 | 25 | 0.6 | 6 |
| MK25-3TW | Rc3/8 | 74 | 25 | 0.6 | 6 |
| MK30-2TW | Rc1/4 | 90 | 30 | 2 | 20 |
| MK30-3TW | Rc3/8 | 94 | 30 | 2 | 20 |
| MK30-4TW | Rc1/2 | 100 | 30 | 2 | 20 |
All 7 listed standard water-model entries are retained. Dimensions are in millimetres and flow values are in L/min. The full model, connection and required installation envelope must be checked together. TW identifies the water-series order form shown in these tables.
Alternative threaded ordering examples
| Published connection-variant example | Arrangement |
|---|---|
| MK25-3TOW | R male connections at both ends |
| MK25-3TOMW | R male inlet |
| MK25-3TMOW | R male outlet |
These codes are examples of alternative connection arrangements. Confirm the dimensions and availability for the requested version; do not assume that every modified fitting has the same installed length as the standard TW model.
Materials, temperature and options
The standard water construction uses an acrylic tube, C3604 brass fittings, SUS304 spring, Nylon 66 ball and nitrile-rubber O-ring. A cylindrical float may be used according to the selected specification. The standard maximum temperature is 80°C and pressure resistance is 1 MPa. These operating limits do not establish a numerical indication accuracy or extend the selected model’s flow capacity.
Installation and commissioning
The spring-supported construction allows upward, downward or sideways mounting. This concerns orientation, not interchangeability of the inlet and outlet: follow the intended flow path and selected fitting arrangement. Keep the viewing area accessible. Match the actual water conditions and required flow with the selected model, check the pipe connection and material compatibility, and inspect for leakage or tube damage after installation. Observe water movement under normal operating conditions and use separate instrumentation where a precise flow value or automatic alarm is required.
Product and dimensional illustrations
Ordering information
Specify the complete water-series model, inlet and outlet thread forms, normal water flow, operating temperature and pressure, and available installation space. State any flow requirement outside the published standard values for a specific selection. State any SUS fitting or heat-resistant construction required.