47
April 2005
®
Vacuum breaker problems
If the vacuum breaker leaks or seems to snap at the beginning or end of a cycle, check the
following:
•
Mounting height — The vacuum breaker must be mounted a minimum of 6 in. higher than
the line to the hood.
•
Nylon check valve travel — Remove the top cap of the vacuum breaker and determine if
the nylon check valve is free to slide up and down the guide stem properly and that the
stem is straight.
•
Rubber washer — Determine if the washer on top of the check valve seats properly
against the machined surface and that the mating surfaces of both are smooth.
Replace if necessary.
Poor drainage
If the hood does not drain properly, look for the following:
•
Clogged outlet — Clear any foreign material (paper towels, rags, etc.) from the hood’s
internal drain outlet.
•
Clogged grease traps — Where grease traps are installed, they may become clogged
and cause drains to back up. If so, they must be kept clear.
•
Drain size inadequate — Drains should be a minimum of 1-1/2 in. dia.
Optional Continuous Cold Water Mist
If the fan runs but no cold water, check for the following:
•
Shut-off valve closed
•
Clogged strainer in the pressure reducing valve.
•
Water solenoid valve
- Check to be sure that water solenoid valve is getting power at the terminal strip.
- Check electrical continuity to determine if coil has burned out.
- Gently tap the valve housing to release any foreign material trapped in the valve.
•
Nozzles may be plugged.
If cold water is running after the fans shut-off, check the following:
•
Solenoid may be stuck in the open position.
•
Is the system in fire mode?
If water leaks from top of the hood then:
•
Check all pipe fittings
•
Ductwork not liquid tight as required.
If little or no water spraying from the nozzles look for:
•
Nozzles plugged and need to be cleaned.
•
Verify the water pressure above 25 psi.
•
Clogged strainer located in the pressure reducing valve.
•
Water supply system not properly flushed.
Reduced pressure backflow preventer (RPBP) may spit small amounts of water as fixtures upstream are
used. Air gap assembly may be needed to catch drips and drain them away to a sanitary sewer.
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