Refrigeration, Hydronics, and Fuel Piping
Refrigeration
Know refrigerant safety classifications, the requirement for listed equipment, and rules for machinery rooms, ventilation, and refrigerant detection where required. Understand that relief devices must discharge to a safe location and that refrigerant piping must be supported and protected. Access for service and labeling of systems are common exam items.
Hydronics
Understand expansion tanks, relief valves, air elimination, and the requirement that relief valve discharge be piped to a safe place of disposal. Know that boilers require relief valves sized to the boiler capacity and that hydronic piping must be supported and protected from freezing.
Fuel piping
Know that fuel gas piping must be installed per the fuel gas code, be listed where required, be supported, and be tested for leaks before being placed in service. Understand shutoff valves, unions, and the prohibition on concealing valves or using certain materials. Know the difference between a sediment trap and a drip leg.
Traps
- Discharging a relief valve where it can scald or where the outlet is plugged or reduced.
- Omitting a sediment trap or installing it incorrectly.
- Concealing a shutoff valve or running fuel piping through prohibited spaces.
- Skipping the required pressure test or testing with the wrong medium.
Worked example
A boiler relief valve discharges to a pipe that terminates 2 inches above a floor drain. Is that acceptable? Only if the discharge is gravity, unobstructed, and directed to a safe place of disposal without a trap or reduction. Rule of thumb: relief discharge must be full-size, gravity, and visible.
Rule of thumb
Test fuel piping before service; never reduce or plug a relief discharge.