MAINTENANCE
2. VOS-2 (valve-open switch) faulty: Check continuity. If switch VOS-2 dœs not break circuit, replace switch.
Covers all 1518/1519 Valves except 1519-X.
If a manual reset or motorized automatic fuel shutoff valve fails to hold open, a few simple checks can be made by qualified personnel. Extreme care should be taken to avoid electrical shock since these tests are performed with power on.
If any valve does not close when de-energized, remove valve from service. After any servicing, always perform prescribed cycling and leak tests before returning valve to service. WARNING: Any valve used for automatic shutoff should be checked on a regular schedule. North American recom- mends cycling (closing and opening) 1518 or 1519 Valves as specified in NFPA86. More frequent checking and cycling is required if the fuel gas is dirty or if the valve is located in adverse (corrosive, dirty, etc.) environment. For main system shutoff, always use a separate, approved manual fuel valve upstream of a 1518/1519 to shut off fuel during down times.
Always shut off fuel supply using a manual tight- shutoff valve upstream of automatic valves.
If valve won't hold open, check for:
1. NO VOLTAGE TO SOLENOID COIL: Check L 1 and L 2 and solenoid coil connections. Check back through flame safeguard system and safety limit circuit per panel manufacturer's instructions. 2. LOW VOLTAGE TO SOLENOID COIL: Check L 1 and L 2 and solenoid coil connections. a. Disconnect leads to coil and check for shorts. If faulty, replace coil. b. Check power supply from control panel.
PARTS REPLACEMENT
Covers all 1518/1519 Valves except 1519-X.
NOTE: Always shut off upstream fuel supply and disconnect electrical power before servicing valve. Identify part locations from the illustrations. Switches and sole- noids are in same location in both manual reset and motorized valves. After servicing, be sure to replace access plate gaskets and all screws to avoid infiltration of dirt or water. All valves are equipped with one DPDT Valve-Open Switch (VOS- 2) and one SPDT Valve-Closed Switch (VCS-1). SOLENOID COILS Faulty solenoid coils are replaced simply by unplugging the wire connectors at the coil, removing mounting screws, placing new coil in position, replacing screws, and reconnecting wires. If wires are replaced to terminal block, follow same routing.
If motor is inoperative, check for:
1. NO OR LOW VOLTAGE TO MOTOR: Check L 1 and L 2 and motor connections.
2. MOTOR LIMIT SWITCH FAILURE: Replace VOS-2 (valve-open switch).
3. MOTOR BURNED OUT: Replace motor operator. Continuous cycling should not occur (see below).
4. MOTOR GEAR TRAIN BINDING: Replace motor operator. Check for continuous operation (see below).
If motor operates continuously, check for:
1. VOS-2 (valve-open switch) not being actuated: Bend switch wand slightly upward.
Instructions 1518/1519 Page 7
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