Download Raypak 751 Operating instructions

Low Water Cut Off (Optional)
PRE-START-UP
The low water cut off automatically shuts down the
burner whenever water level drops below the level of
the sensing probe. A 3 second time delay prevents
premature lockout due to temporary conditions such
as power fluctuations or air pockets.
Fill the System:
1. Close manual and automatic air vents and drain
cock.
2. Fill to correct system pressure. Correct pressure
will vary with each application.
3. Open automatic air vent two turns.
4. Slowly feed water to boiler.
5. Starting on the lowest floor, open air vents one at
a time until water squirts out. Close vent.
6. Repeat with remaining vents.
7. Close manual water feed valve when correct boiler pressure is reached.
Inspect Venting System:
1. Check all vent pipe connections and flue pipe
material.
2. Ensure vent terminations are installed per code
and are clear of all debris or blockage.
Fig. 35: Low Water Cut Off
High and Low Gas Pressure
Switches — Manual Reset
For Your Safety — Read Before
Lighting
The low gas pressure switch mounts upstream of the
gas pressure regulator to ensure that sufficient gas
pressure is present for proper regulator performance.
The low gas pressure switch automatically shuts down
the boiler if gas supply drops below the factory setting
of 6 in. WC for Natural gas, and 10 in. WC for Propane
gas.
WARNING: If you do not follow these instructions
exactly, a fire or explosion may result causing
property damage, personal injury or loss of life.
1. This appliance has an intermittent pilot. It is
equipped with an ignition device which automatically lights the pilot. DO NOT try to light the pilot or
burner by hand.
The high gas pressure switch (optional) mounts downstream of the gas pressure regulator. If the gas
pressure regulator fails, the high gas pressure switch
automatically shuts down the burner.
2. BEFORE OPERATING, smell all around the appliance area for gas. Be sure to smell next to the
floor because some gas is heavier than air and will
settle on the floor.
3. WHAT TO DO IF YOU SMELL GAS:
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Do not try to light any appliance.
Do not touch any electrical switch; do not use
any telephone in your building.
Immediately call your gas supplier from a
neighbor's telephone. Follow the gas supplier's instructions.
If you cannot reach your gas supplier, call the
fire department.
4. Use only your hand to push in or turn the gas control knob. Never use tools. If the knob will not turn
by hand, do not try to repair it, call a qualified service technician. Forced or attempted repair may
Fig. 36: Gas Pressure Switch
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