Magnetically actuated piston switch with a solid machined 316 stainless-steel body — 200 bar pressure rating, handles liquids up to 90 °C. Ideal for hot/cold water pressure boosting, gravity hot-water systems, safety showers and other high-reliability applications.
UB25 Series
Inline Flow Switches
Features
- Suits 25 NB (1 inch) pipes
- Versatile all-position mounting
- 200 bar / 2900 psi pressure rating
- Switches at very low flows
- IP67 weatherproof housing
- Solid machined 316 stainless metal body
- High flow-through rating
- Handles liquids up to 90 °C
- 1.5 L/min switching point on a slowly rising flow as supplied (0.23 L/min with the non-magnetic piston retainer)
The UB25 body is machined from solid 316 stainless steel. Inside, a free-sliding piston (glass reinforced polypropylene; nylon on Dieseline -D models) is pushed back by flow until the liquid passes around it. The piston actuates a magnetically-linked switch and is pushed back to the off position by magnetic repulsion when flow stops — there are no springs in the wet area. The piston and electrical housing are glass reinforced polypropylene. 25 mm (1″) BSPT male inlet and 1″ BSPT female outlet; three electrical modules available, plus a Dieseline -D model.
More Information
Select Model
Trade customers should contact sales@kelco.co.nz for account pricing.
Ordering — Available Models
| Model Number | Description |
|---|---|
| UB25-B | Dry reed switch S.P.S.T. N.O. — 50 W, 250 V AC / 200 V DC, 1.5 A max. Not suitable for inductive loads. PLC and general control circuits. |
| UB25-B-D | Dieseline model — nylon piston in place of the glass reinforced polypropylene piston; otherwise as UB25-B. |
| UB25-C | Dry reed switch S.P.D.T. break before make — 20 W, 140 V AC / 150 V DC, 1 A max. Not suitable for inductive loads. PLC control and safety showers. |
| UB25-C-D | Dieseline model — nylon piston in place of the glass reinforced polypropylene piston; otherwise as UB25-C. |
| UB25-R | Solid state relay S.P.S.T. N.O. — 740 W, 12 to 240 V AC, 4 A continuous (spike to 15 A); inductive loads 4 A at 240 V AC. AC control circuits and AC motor control. |
| UB25-R-D | Dieseline model — nylon piston in place of the glass reinforced polypropylene piston; otherwise as UB25-R. |
Operating Limitations
| Maximum recommended operating pressure (static or dynamic) | 200 bar / 2900 psi |
|---|---|
| Minimum burst pressure | 400 bar / 5800 psi |
| Maximum liquid temperature | 90 °C |
| Minimum liquid temperature | -20 °C |
| Maximum recommended continuous flow (water) | 100 L/min |
| Switching point on a slowly rising flow (±15%) | 1.5 L/min as supplied (standard magnetic piston retainer); 0.23 L/min with the non-magnetic piston retainer fitted |
| Switching point on a slowly falling flow (±15%) | 1.2 L/min as supplied (standard magnetic piston retainer); 0.18 L/min with the non-magnetic piston retainer fitted |
| Minimum gravity head required to actuate the switch | 1.5 metres |
| Switching point sensitivity | Standard magnetic piston retainer fitted as supplied. A non-magnetic piston retainer is also supplied with each switch; fitted vertically with upward flow, it lowers the flow rate needed to actuate the switch by approximately 6.5 times. |
| Process connection | 25 mm (1″) BSPT male inlet, 1″ BSPT female outlet |
| Ingress protection rating | IP67 |
Dimensions
Warning: Electrical Safety
The UB25 Series flow switch is a mains voltage device. Death or serious injury may result if this switch is not correctly installed and operated. All electrical work on this switch must be performed by a fully qualified and licensed electrician.
Two Piston Retainers Supplied
The UB25 is supplied as standard with a magnetic piston retainer that allows the switch to be oriented in any required position in pipework; in vertical pipework flow can be either upward or downward through the switch. A non-magnetic piston retainer is also supplied with each switch — when this is fitted, the switch must be oriented vertically with flow passing upward through its body, and the flow rate required to actuate the switch is approximately 6.5 times lower (0.23 L/min rising and 0.18 L/min falling, ±15%, against 1.5 and 1.2 L/min as supplied). It is commonly used to enhance the sensitivity of the switch in gravity head applications such as boosting water pressure in gravity fed hot water systems.
Dieseline Model (-D)
Order the -D suffix (e.g. UB25-B-D) for the Dieseline model. The piston is glass reinforced polypropylene on standard models and nylon on Dieseline -D models. The solid 316 stainless steel body is suitable for neutral liquids such as hot or cold water, or oils.
Mounting & Pump Installation
The UB25 can be mounted in any orientation in the pipework, including upside down, in horizontal or vertical pipework. There is a direction of flow arrow on the electrical enclosure; the switch will not operate against a reversed flow. Pipework can be used to support the switch, or it can be screwed directly into valve manifolds or pump ports — use thread tape or sealant. Do not use this flow switch as a non-return valve. In the typical pressure boosting installation the switch is fitted to the pump discharge, with a Y strainer on the pump inlet and a non-return valve downstream of the flow switch.
Clean Fluid & Line Filtration
The UB25 contains a close fitting piston and should only be used where the process fluid is reasonably clean and free of entrained or suspended material. It should not be used with fluids containing large particulate matter, ferrous materials or fibrous matter. If the degree of contamination of the process fluid can’t be guaranteed, fit suitable line filtration to the system.
Servicing the Piston
To service the piston or to install the non-magnetic piston retainer, use long nosed pliers to remove the spring circlip in the outlet port of the switch. Press the piston back with your finger; it should pop out along with its three finned magnetic retainer. Ensure there are no pieces of iron scale adhered to the piston or retainer and that both parts are free of damage. Reassemble the switch and test it to ensure the piston is a free and smooth fit.
Typical Applications
Hot and cold water pressure boosting, gravity hot water system control, hot water circulation actuation, safety shower alarm sentinel, wash down pump control, solar hot water control, mains pressure boosting and constant pressure pump control.
Hazardous Areas
The UB25-B and UB25-C (including -D models) are simple apparatus under AS/NZS 60079.11 and may be used in a hazardous area only as part of an intrinsically safe circuit, connected through suitably certified associated apparatus. They are not Ex certified in their own right. The full conditions of use are given in the installation sheet. The UB25-R and UB25-R-D are not certified for use in hazardous areas and must not be installed in any area classified as hazardous under AS/NZS 60079.10 (Zone 0, 1, 2, 20, 21 or 22).
Serviceability
Fully field-serviceable. To service the piston, remove the spring circlip in the outlet port; most components of the switch are available in spare part kits. The electrical module unscrews from the stainless body without disturbing pipework. Spare pistons (water and dieseline variants), seals and electrical modules available from Kelco Engineering or your distributor.
