The Potter OSYSU-1 is an outside screw and yoke (OS&Y) valve supervisory switch with one set of SPDT (Form C) contacts. It monitors the open position of an OS&Y gate valve and signals the fire alarm system when the valve is closed or the switch is removed.
The OSYSU mounts on most OS&Y valves from 2 in. to 12 in. (50 to 300 mm) and on some valves as small as 1/2 in. (12.5 mm). The cover is held by two tamper-resistant screws, and the special tool to remove them is furnished with each device.
Specifications
| Contacts |
One set of SPDT (Form C) |
| Contact ratings |
10.0 A at 125/250 VAC; 2.0 A at 30 VDC resistive; 10 mA minimum at 24 VDC |
| Valve size |
2 in. to 12 in. (some valves down to 1/2 in.) |
| Enclosure |
NEMA 4X (IP65) and NEMA 6P (IP67); indoor or outdoor |
| Operating temperature |
-40 to 140°F (-40 to 60°C) |
| Conduit entrances |
Two knockouts for 1/2 in. conduit |
| Construction |
Composite cover; die-cast base, black powder coat |
| Weight |
1.6 lb (0.73 kg) |
| Service use |
NFPA 13, 13D, 13R, 72 |
Installation notes
- Three-position switch detects valve closure and removal of the switch from the valve
- Must operate within the first two revolutions of the valve wheel toward closed
- Restores to normal only when the valve is fully open
- Adjustable length trip rod and knurled mounting bracket that resists slipping
- Accepts up to 12 AWG wire; visual switch indicators confirm the normal position
- Potter recommends testing quarterly or more often, per the AHJ
Related models
The OSYSU-2 has two sets of SPDT contacts, and the OSYSU-2-CRH adds corrosion-resistant mounting hardware. For hazardous locations, Potter offers the OSYSU-EX (bulletin 5400705).
Documents
FAQ
What is the difference between the OSYSU-1 and OSYSU-2?
The OSYSU-1 has one set of SPDT (Form C) contacts; the OSYSU-2 has two sets.
What valve sizes does it fit?
Most OS&Y valves from 2 in. to 12 in. (50 to 300 mm), and some valves as small as 1/2 in.
Can it be installed outdoors?
Yes. The enclosure is rated NEMA 4X (IP65) and NEMA 6P (IP67) for indoor or outdoor use when suitably rated conduit and connectors are used. For hazardous locations, see the OSYSU-EX.
How is it tested?
Turn the valve wheel toward closed: the switch must operate within the first two revolutions. Fully close the valve to confirm it does not restore, then fully open it and confirm it restores only when fully open.
