5.5.7.14  Troubleshooting : Things to Check

Each of the following monitor points must report a nominal condition to the gas interlock panel in order for the logic to be "made up" and for gas flow to be enabled:

 

Low Pressure The seconeary Check for a closed 3 pressure

pressure of one or "Excess Flow" Valve, switches located

more of the mixer Remedy the cause, and on the "Delivery

inlet gas supplies reset the valve Rack"

has dropped below Replace empty supply

the 45 psi bottle. threshold.

Gas Shed Airflow Gas Shed Exhaust Restore forced Vane Switch

Fan ( ceiling of ventilation. mounted just

"Isobutane Room') inside exhaust

has failed. fan

Overtemp Gas Shed Temperature in Gas Take action to protect Klixon mounted

Shed Too High equipment. in rack

(110^oF). Reduce temperature.

Over-Pressure FPP VDC/FPP Exhaust Eliminate exhuast line PHOTOHELIC^(R)

Over-Pressure VDC manifold pressure blockage gauges on gas

Electron at Hadron Or Allow Hall-A panels in shld

Over-Pressure VDC Electron Shield atmospheric pressure to houses

Hadron House Gas Rack stabilize

Gas Leak Flammable gas Localize leak by GASMASTER

detection system referring to readings on HydroCarbon

has sensed a leak GasMaster-4 system in Detector heads in

Counting House Gas Shed and

Fix Leak each Shield House.

Overtemp Electron Temperature in Take action to protect Klixon mounted

Electron Shield equipment. in gas rack in

House Too High Reduce temperature Electron Shield

(110^oF). House

Overtemp Hadron Temperature in Take action to protect Klixon mounted

Hadron Shield equipment. in gas rack in

House Too High Reduce temperature. Hadron Shield

(110^oF). House

Post-Bubbler Gas pressure out of Reset Dynamass Pressure switch

Supply mixer/bubbler rack Controller in rear of Mixing

Overpressure is >18 psi. If needed, vent excess Station

pressure using MV-299 (mixer/bubbler rack)

Resetting a closed Excess Flow Valve

Each Excess Flow Valve automatically closes if the flow rate through it exceeds about 4 slpm at 45 psig. The exact flow threshold varies somewhat depending upon the delivery pressure.

These valves must be manually reset after they trip. This is done by rotating the red handle 90^o CW (to OPEN/RESET ) and then 90^o CCW (back to AUTO SHUTOFF. ). It will be necessary to keep the valve in the OPEN/RESET position for about 10 seconds until nominal pressure builds up downstream. The excess flow valves must be returned to the AUTO SHUTOFF setting to insure system safety.

Restoring flow after a "Low Supply Pressure" shutdown

If the gas pressure in any enabled supply line to the mixer rack drops below about 40-45 psig, the interlock will sound an alarm and close all of the solenoid valves. This prevents the system from delivering a bad mixture to the detectors. After restoring the gas supply, for example, after replacing an empty gas cylinder, perform the following steps to restart the flow of gas.

1.

Verify that no faults other than "Low Pressure" and "Main Relay" are indicated on the gas interlock panel.

2.

Insure that all high-pressure manifolds are pressurized and that the secondary pressures indicated by the gauges above the bottles are at about 40-45 psig (normally these should not need adjustment).

3.

Press the Low Pressure Override button on the interlock panel in the gas shed.

4.

Reset all Excess Flow Valves by turning their handles to OPEN/RESET, waiting for about ten seconds, then returning their handles to AUTO SHUTOFF.

5.

Verify that all faults are now cleared on the gas interlock panel.

Restarting flow after a power failure.

Normally the gas control system is protected from power outages by an uninterruptable power supply (UPS). If the system is nevertheless disturbed by a loss of power then perform the steps outlined in section 3.2, Startup Procedure.