Power Engineering 4th Class Ch 111
d
Building codes generally limit the highest pressure permissible in plumbing systems to: Choose one answer. a. 350 kPa b. 490 kPa c. 500 kPa d. 560 kPa e. 600 kPa
b
Building codes recommend that nowhere in a building plumbing system should the water pressure fall below: Choose one answer. a. 100 kPa b. 175 kPa c. 350 kPa d. 490 kPa e. 560 kPa
b
In a circulating hot water system the municipal distribution systems and/or local storage tanks are used for which of the following reasons. a) Cold water supply only b) Water supply to heaters only c) Hot water supply from municipal heating stations d) Both cold water and heater water supply e) Water meter rationing
b
In a domestic circulating hot water system, automatic air vents serve to: Choose one answer. a. Relieve pressure from the hydro-pneumatic tanks b. Remove air that is released when water is heated c. Supply air to cooling water in the storage tank d. Aerate the water e. Prevent air from being dissolved in the water, thus inhibiting corrosion
c
Most building regulations prohibit single pipe systems over ________ in length from a hot water heater or hot water recirculating line. Choose one answer. a. 10.5 m b. 12.2 m c. 15.2 m d. 20.5 m e. 25.5 m
a
Most municipal water distribution systems operate at pressures between: Choose one answer. a. 350 and 490 kPa b. 250 and 490 kPa c. 150 and 500 kPa d. 0 and 100 kPa e. 20 and 90 kPa
b
Temperature relief devices are effective in protecting domestic hot water systems from which of the following problems? Choose one answer. a. Scale build up in the system b. Flashing of water to steam when faucets are opened c. Venting off air released from water during heating d. Inadequate heating of the water e. Water stagnation
d
Temperature relief devices limit the temperature in domestic hot water systems to no more than: Choose one answer. a. 50°C b. 79°C c. 90°C d. 99°C e. 121°C
c
The back flow prevention method consisting of two independent check valves with an automatic operating pressure differential relief valve located between them is called: Choose one answer. a. Air gap back flow prevention b. Double check valve c. Reduced pressure principle device d. Atmosphere vacuum breaker e. PVB
d
The building water system that has a storage tank above the highest fixture in the system is called: Choose one answer. a. An up feed system b. A constant pressure system with suction tank c. A tank less constant pressure system d. A down feed system e. A direct pressure system
c
When the maximum building demand for water is always less than the maximum flow available from a municipal or local distribution system which of the following systems can be used? Choose one answer. a. A constant pressure system with suction tank b. A constant pressure system with pneumatic tank c. A tank-less constant pressure system d. A down feed system e. A gravity system
a
Which of the following is not an element found in a circulating hot water system? a) A fire recoil element b) Air vents c) Heaters d) Back flow valves e) Return Piping
b
Which of the following statements about a constant pressure water system that has a pneumatic tank is false? Choose one answer. a. Water entering directly into the pump suction is discharged into a pressurized tank b. This system is primarily used in larger buildings c. A system controller automatically starts a standby pump in the event of pump failure d. The system has a pressure regulator to maintain a relatively constant pressure above the water level inside the tank e. Air must continuously be introduced into the tank
e
Which of the following statements about a pressure relief valve in a building hot water system is false? Choose one answer. a. The valve may be installed anywhere in the hot water system close to the heater or tank b. The valve discharge must NOT be directly connected to a drain or vent pipe c. The valve is opened by pressure in the line surpassing a preset pressure set on the spring in the valve d. The valve is automatically closed when the water line pressure drops below the spring pressure setting e. The relief valve may be isolated from the vessel it serves by means of a gate valve, for the purposes of maintenance.
a
Which of the following statements about non-circulating hot water systems is true? Choose one answer. a. The systems cause large amounts of water to be wasted before hot water is available at the fixtures b. The systems are used in large residential buildings c. The systems eliminate hot water stagnation d. The systems provide immediate hot water to all fixtures without the need of a pump e. The systems have a return line
b
Which of the following statements about pressure relief valves is false? a) The valve may be installed anywhere in the hot water system close to the heater or tank. b) The valve must be directly connected to a drain or vent pipe. c) The valve is opened by pressure in the line surpassing a preset pressure set on the spring in the valve. d) The valve is automatically closed when the water line pressure drops below the spring pressure setting. e) None of the above.
