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Hvacr unit 66
Terms in this set (42)
Heat source in heating and heat sink in cooling
Geothermal uses ground as what in heating and cooling?
Geothermal Heat Pump
What systems move heat from the earth into your house?
At depths below what, the earth temperature is nearly constant?
Open Loop System
What are open to air and are supplied with water from a well, it is not recirculated?
Inner tube, outer tube, opposite directions
In the water coil, water travels through the what, and the refrigerant flow through what, they travel in which directions?
The water coil in a water-source unit is a what tube in tube coil?
The water-source unit's capacity is less variable because the water being supplied to it must be what in temperature?
Do water-source units require suction line accumulators or charge compensators?
Most water-source packaged units use what for a metering device?
Do heat pumps need a defrost cycle?
Inside the Building
With all water-source heat pumps, the compressor and refrigerant components can all be located where?
Where do geothermal systems get there heat source?
Geology, hydrology, and land availability
The site for a geothermal system must be evaluated with regard to what?
They extract heat from the ground, which is a stable temperature
Geothermal systems do not lose capacity as the temperature drops because why?
Indirect water-to-water heat exchanger
Wheat coil on a water-source heat pump, is located inside the tank and isolates the domestic water from the heating water?
What is available in several configurations, including wall mount, floor mount, ceiling mount, compact cassette, and low-static ducted units?
Where is the metering device on a mini-split system?
Line in carries low-pressure, low temp saturated liquid and vapor mix/ Line out carries low-pressure superheated vapor
What do the lines in and out carry on a mini split system in cooling?
The refrigerant lines on a mini-split are usually connected with what?
What has flare nuts with thicker walls, a 45 degree angle, and the flared ends of the tubing are a little larger in diameter than regular flares?
Outside and then power is run from there inside
Where is all the power for a mini split system supplied?
A condensate lift kit/ condensate pump
What is used where a ceiling mount or a ceiling cassette cannot use a gravity drain because a gravity drain would have to come straight down the middle of the room?
Most multisplit units require connection to how many units, but not all circuits have to be used?
Is it possible for an indoor multisplit system to heat while another cools?
Designing a heating and cooling system to accommodate what can allow buildings to operate with less installed capacity and still meet the demand?
Large VRF systems can combine up to how many outdoor units manifolded together to increase overall system capacity?
Inverter-driven compressor and electronic expansion valves
VRF systems use what type of compressors and what type of valves to change the volume of refrigerant being circulated in the system?
Branch selection boxes
What is used to connect all the indoor units to one large interconnected refrigerant piping system?
Heat recovery systems
What allows simultaneous operation of heating and cooling, some indoor units may be operating in cooling while others are operating in heating?
Headers and branch joints
What are used to create the refrigeration network used in a VRF?
If both headers and branch joints are being used, which one comes first?
What is designed like a wye, but is carefully designed to insure even refrigerant flow to both branches with a minimum of turbulence and pressure drop?
Within sight of unit
A weatherproof disconnect should by placed where?
Power, low voltage communication, line voltage power and low voltage communication, ground
Whether the system is a straight air conditioner of a heat pump, four wires are usually run from the outdoor unit to the indoor unit, what are those wires?
Some manufactures required how long for a pressure test before evacuation?
Nitrogen, 24 hours, Nitrogen, 500
To pressure test a system, pressurize the system with "what" up to the manufacturers recommended test pressure, wait "how long" to insure the system holds, release "what", and evacuate to below "how many" microns?
Read manufacturers installation instruction will specify maximum total installed piping length, will specify add for additional foot of refrigerant line
How do you charge multisplit units?
How is a four-wire conductor on a multisplit system often labeled?
Manufacturers recommend pressurizing the piping to what psig?
VRF system are usually what type of systems?
Three-phase outside and single-phase inside
VRF systems are normally designed to operate on what power inside and outside?
Entire system into one area
Because VRF systems are connected in one large refrigerant network, it is possible for a leak to release where?
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