Ch 40
Reversing valve
A 4 way manifold controlled by a solenoid valve that can reverse the flow of refrigerant
Charge compensator tank
A canister w the heat pump's gas lines running through it
Reverse cycle defrost
A defrost method that reverses refrigerant flow through and air source heat pump
Water loop
A heat exchanger that circulates refrigerant through one passage and water through a separate but adjacent passage
Direct-exchange (DX) heat pump
A heat pump that circulates refrigerant through an outdoor coil placed in direct contact w the earth
Ground source heat pump
A heat pump that uses the earth as a heat source or a heat sink for producing the desired temperature in a conditioned space
Air source heat pump
A heat pump that uses the outside air as a heat source or a heat sink for producing the desired temperature in a conditioned space
When a heat pump is operating in COOLING MODE
A heat pumps reversing valve changes position, causing the refrigerant to flow in the opposite direction
Air coil
A length of tubing that contacts air and circulates refrigerant
Ground Coil
A length of tubing that contacts ground and circulates refrigerant
Ground loop
A length of tubing that contacts the ground and circulates water
Water coil
A length of tubing that contacts water and circulates water
Ideally, the refrigerant charge of a heat pump should be checked when the outdoor temp is
Above 70F for cooling and below 40F for heating
Solar panels
Absorb heat from the sun and transfer the heat to water in a heat storage tank
Biflow bypass TXV
Allows refrigerant to flow in either direction by using an internal check valve
Crankcase Heater
An electric resistance heater that warms the compressor dome prior to compressor start up
Heat pump compressors
Are required to operate at lower ambient temperatures than most ac compressors
Metering devices must
Be sized for a specific amount of refrigerant flow
Heat pumps use another refrigerant storage called a _______
Charge compensator tank
A heat pump requires more refrigerant in
Cooling mode
Ground source heat pump
EPA's most efficient heating and cooling system
E
Emergency heat or auxiliary heat
G
Fan control
W1
Heating stage 1 or auxiliary heat
The best way to eliminate bacteria and mold growth in a heat pump system is to
Install an ultraviolet light
In a heat pump the direction, of refrigerant flow through its compressor
Is always in the same direction
Biflow metering TXV
Meters refrigerant flowing in either direction
Flow check piston
Meters refrigerant passing through it in one direction and allows refrigerant to pass freely in the other direction
Fixed orifice metering devices and cap tubes are not well suited for
Most heat pump applications
The most convenient way to deal w the problem of snow accumulation is to ___
Mount the outdoor coil on risers
After blowing out a drain line, flush the drain line w ____
One part household bleach to four parts water
A heat pump's crankcase heats warms the compressor to vaporize any liquid refrigerant that may have entered the compressor during _____
Prior to start up (off cycle)
Instal a check valve in tubing that runs parallel w each TXV to allow
Proper refrigerant flow
B
Reverse valve
Heat pump compressors are
Similar to compressors in standard ac units
A heat pumps compressor is protected from liquid slugging by a
Suction line accumulator
Solar panels are sized to meet
The auxiliary heating needs of a heat pump
When a heat pump is operating in HEATING MODE
The outdoor coil functions as an evaporator by absorbing heat
Outdoor coil
The refrigerant coil that absorbs or expels heat for the indoor coil
Indoor Coil
The refrigerant coil that is located inside and warms or cools the air for the conditioned space
During the HEATING MODE, the gas line is colder than the liquid line, causing ____
The warmer refrigerant from the liquid line to condense and flow into the charge compensator tank
Air-to-water heat pump
Transfers heat between outside air and air inside a conditioned space using a hydronic system for heat distribution
Air-to-air heat pump
Transfers heat between outside air and air inside using forces air for distribution
Water source heat pump
Type of heat pump that circulates water through a secondary circuit that is laced underground or underwater
Direct acting reversing valves
Uses the direct mechanical action of the solenoid plunger to move the piston and sliding section of tubing inside the reversing valve/ used in smaller heat pumps
Pilot-operating reversing valve
Uses the pressure difference between the compressors suction and discharge lines to move its piston
3 major Occasions when auxiliary heat is needed
When outside temp is too low, during reverse cycle, and for emergency operation when a compressor is inoperable
During COOLING MODE, the gas line is warmer than the liquid line,
Which causes the liquid refrigerant in the tank to boil and circulate through the system as needed
