Maintenance Procedures
Check Combustion/ Ventilation Air Openings
Verify that all combustion air and ventila- tion openings to the mechanical room or building are open and unobstructed. Check the operation and wiring of any automatic ventilation dampers.
Check and verify the vent discharge and the combustion air intake are free of debris and obstructions.
Inspect Vent System and Combustion Air Piping
Visually inspect the venting system and combustion air piping (if installed) for blockage, deterioration or leakage. Repair any vent joints that show signs of deterio- ration as per the vent manufacturer’s instructions.
When combustion air is ducted to the unit, verify that the air inlet piping is connected and sealed. Inspect the air hose connecting the air inlet adapter to the venturi elbow for deterioration.
WARNING
Failure to inspect the vent system and combustion air inlet piping and have any conditions repaired can result in severe personal injury or death.
Check Primary System
Verify all system components are correctly installed and operating correctly.
Check the cold fill pressure for the system, typical cold water fill pressure is 12 psig.
Verify the system pressure as the unit oper- ates at high temperature to ensure the pres- sure does not exceed 25 psig. Excessive pressure reading indicates expansion tank sizing is incorrect or system performance problems.
Inspect air vent and air separators in the system. Remove the caps on automatic air vents and briefly depress the valve stem to flush vent. Replace the cap when complet- ed. Ensure vents do not leak, replace any leaking vents.
Check Domestic System
Verify all system components are correctly installed and operating correctly.
Check the outlet domestic temperature of the mixing valve and compare with the recorded temperature made during
Check Expansion Tank
Refer to Section V - Primary Piping for recommended location of the expansion tank and air eliminators.
Close
-Ensure tank is partially filled with water leaving an air gap as a cushion. Refer to the manufacturer’s instruction for proper fill level.
-Ensure the tank is fitted with a device that reduces gravity circulation of air- saturated tank water back into the sys- tem. This device prevents air from bubbling up through the water as it returns from the system.
-Ensure no automatic air vents are used in the system. This will allow air to escape from the system instead of returning to the tank.
Diaphragm Tank:
-Ensure the system contains a minimum of one automatic air vent. Preferred location of the air vent should be atop an air eliminator.
-Remove the tank from the system and check the charge pressure. For residen- tial applications the charge pressure is typically 12 psig. If tank does not hold a charge pressure, then the membrane is damaged and the tank should be replaced.
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