Portable extension ladders should extend a minimum of ______________ above the edge of the roof.

The advantage of using a pump-down control on a commercial refrigeration system is to:

   To burn Propane in a natural gas appliance

Which of the following statements would be correct concerning the refrigeration cycle?

Size section #2 in the drawing above using the longest length method and the pipe sizing tables in the International Fuel Gas Code. The natural gas supplied has a 0.60 specific gravity and a heating value of 1000 Btu per cubic foot with a designated pressure drop of 0.5 inches W.C. The material is schedule 40 black iron pipe.

In the HVAC and plumbing industry, steel pipe is usually joined by _______________ pipe threads.

The ladder schematic diagram is made up of _____________________.

Before working with chemical solvents, oils and refrigerants, the technician should review:

Floor furnaces shall not be closer than 6 inches to the nearest wall and not less than _____ inches from the two adjoining sides

Excess air for combustion appliances consists of: