Hvac Final Chapter 5

Copper tubing must be properly supported to prevent sagging or buckling. On horizontal runs of hard temper tubing, the maximum support spacing for 1/2- and 3/4-inch tube is ____ feet.

5

A feed water valve is used to increase the pressure of water from a domestic water distribution pipe before it enters a hydronic system.

False

A well-planned piping assembly will use the largest number of fittings possible.

False

Hydronic heating systems should never use a combination of flexible and rigid piping materials.

False

In situations where both piping and electrical wiring are in close proximity, try to keep the piping above the electrical wiring.

False

Plumbing codes allow solders containing lead to be used for domestic water service.

False

Some press fittings used in residential and light commercial buildings are rated to operate at pressures up to 200 psi and temperatures ranging from 0 to 250 ºF.

False

______ are designed specifically for component isolation.

Gate valves

Copper water tube is available in three wall thicknesses designated as types ____ in order of decreasing wall thickness.

K, L, and M

____ tubing consists of high-density polyethylene that has undergone molecule modification that creates sufficient tie chains between the polyethene molecules to allow it to operate at higher temperatures.

PE-RT

________ are used to secure piping to either walls or ceilings.

Standoff piping supports

ASTM F876 standard for PEX tubing establishes three simultaneous temperature/pressure ratings based on operation with water.

True

Due to thermal expansion, the greater the length of the pipe, and the greater the temperature change, the greater the change in length.

True

In the absence of any building or mechanical codes that require otherwise, type M is the standard for copper tubing used in hydronic heating systems.

True

Piping schematics are the road maps of hydronic system design. Unfortunately, there is no universal standard for piping symbols to which all those in the hydronics industry subscribes.

True

There is___ universal standard for piping symbols to which all those in the industry subscribe.

a rigid

Unlike PEX tubing, PEX-AL-PEX tubing cannot be repaired by heating the tub until the PEX reaches its____ state.

amorphous

A(n)_____ is commonly used to mount an air vent at high points in piping circuits.

baseboard tee

Fittings for copper tubing are available in either wrought copper or ____.

cast brass

When long straight runs of rigid tubing are required, it may be necessary to install an expansion loop or an expansion offset to absorb the movement. Another alternative is to install an expansion ____ capable of absorbing the movement.

compensator

In situations where good heat transfer through the walls of the pipe is desirable, ____ is unsurpassed.

copper

Some common pipe fittings in hydronic systems include___________.

couplings, elbows, and tees

Feed water valves operate by balancing the force generated by water pressure against an internal flexible ____, with the counterforce generated by a partially compressed spring.

diaphragm

The smaller the coefficient of linear expansion, the_____ tubing expands for a given change in temperature.

less the

Another specialty valve widely used in hydronic systems provides the ability to isolate, flow balance, and even drain individual heat emitters. It is called a ____.

lockshield valve

In situations where several runs of piping and/or electrical conduit must be run in close proximity, a ____ system is a good option.

mounting rail

If the inlet pressure on the backflow preventer drops below the pressure in the hydronic system, springs return both check valves and the movable cartridge to their ____ positions.

original

The driving force of________ is a lower concentration of dissolved oxygen molecules within the water inside the tube, compared to the concentration outside the tube.

oxygen diffusion

Hydronic heating systems, once assembled, must be purged of air and filled with fluid. A(n) ____ is specifically designed for this purpose.

purging valve

When soldering copper tubing be sure the tube cut is square. Use a(n) _______ with a blade suitable for the copper tubing.

wheel cutter or chop saw

A device used to allow or prevent flow through a zone circuit is called a(n)_____.

zone valve