Hydronic Environmental Systems Quizzes Questions for Final

If 120 volts is applied to a closed switch, and you had one meter lead on each side of the switch, what should your meter read?

0 volts

It is vital that the solar collectors and all exposed piping in a drain-back system be pitched a minimum of ____ toward the storage tank to allow complete drainage.

1/4 in./ft.

If you had more than one zone valve controlling a boiler, the end switch circuit would be______.

An "or" circuit

A priority zone is usually used for ______.

An indirect hot water heater

Heat source reset, and mixing reset can never be used together.

False

In floor heating water setpoint should always stay at least 190 degrees F to insure adiquate output to the space.

False

In full storage ETS systems, all energy used during the subsequent on-peak period is purchased and stored during the peak cycle.

False

It is not advisable to maintain water flow through the condenser whenever the heat pump is operating.

False

Many boilers traditionally used in North America were designed with the intent that flue gases would condense within the boiler.

False

The heating capacity of the heat pump drops rapidly with increasing source water temperature.

False

A closed loop control system gets feedback from the controlled device

True

Condensing boilers are designed with large heat exchanger surfaces capable of extracting more heat from the exhaust gases compared to the heat exchangers in conventional boilers.

True

Conventional gas- and oil-fired boilers are currently used in the vast majority of residential and light commercial hydronic systems in North America.

True

If a cast-iron boiler is significantly oversized and experiences long off-times between firing cycles, much of the heat stored in the boiler's thermal mass can be carried up the flue by air currents passing through the combustion chamber.

True

The cast-iron sectional boiler is currently one of the most common boilers used in residential and light commercial buildings in North America.

True

The decision to use a wood-fueled boiler involves a time commitment much more demanding than for conventional heat sources operating on natural gas, propane, fuel oil, or electricity.

True

The term "hydronic heat pump" always refers to a heat pump that delivers heat to a flowing stream of water.

True

Fuzzy logic refers to_______.

an advanced microprocessor that uses advanced algorythms and internet access to learn

A typical hydronic zone valve has 2 wires for _______, and 2 wires for _______.

an end switch, a motor

An analog input is ______.

any electrical or pressure value in a certain range

A typical aquastat relay normally contains_______.

burner relay, pump relay, and high limit

Most cast-iron sectional boilers are limited to use in ____ hydronic systems.

closed loop

Analysis of combustion processes reveals that significant amounts of heat can be recaptured from the exhaust stream if the water vapor it contains can be ____.

condensed within the boiler

A flow restriction or stoppage in the ____ can lead to rapid formation of ice crystals on the cold heat exchanger surfaces separating the water and refrigerant.

evaporator

in an outdoor reset control, the boiler temp ______ as the outside temp ______.

goes down, goes up

A ____ is a device for moving heat from one area to another using a refrigeration cycle.

heat pump

Boilers with low thermal mass tend to have ____ cycle efficiencies due to lesser amounts of heat remaining in the boiler following burner shutdown.

higher

Too large a differential will cause ______.

large swings in temperature

On a reset curve, the minimum water temp setting ______.

prevents condensation in the boiler

PID controls means ______ control.

proportional integral derivitive

The difference between the target temperature and and actual temperature is called______.

proportional offset+

An "and" circut refers to a _______ circut.

series

A boiler operates at _____ efficiency only when it is being fired continuously under non varying conditions.

steady-state

Turn down ratio in hydronic systems refers to ______.

the ratio between maximum and minimum output

The best control for a given application is ______.

the simplest control that does the job well

The zone motor is usually controlled by_______.

the thermostat

The combination of metal and water weight gives cast-iron boilers the ability to absorb a significant amount of heat. Such boilers are said to have a high ____.

thermal mass

In solar anti-freeze based combisystems, the outside heat dump provides a way for the system to shed excess heat. It is activated if the temperature of the thermal storage tank reaches a ____ upper limit.

user set

A delay on make control will_____ when power is applied

wait a specified amount of time then come on

One type of boiler design surrounds the combustion chamber with a water-filled heat exchanger. This arrangement is called a ____ boiler.

wet base