things that make you go HMMMMMM
what is the most common complaint from a customer changing from gas heat to a heat pump
cold air at high velocities out of the registers
which component is responsible for changing the direction of the flow of refrigerat
reversing valve
during the defrost cycle, the outdoor fan is usually
turned of
on a split system heat pump, a "no heat" service call, you turn the thermostat to the fan on/ cont position and the indoor fan operates. the action verifies that
the transformer is functioning
during the defrost cycle, the system switches to the ______ mode
cooling
what a heat pump is operating in the heat mode, the suction line at the compressor will feel
cold and sweaty
some heat pump systems use a ______ as a metering device
fixed orfice
systems rated at 7.5 toms and higher, which use the thermostatic expansion valve at each coil will also have
a bypass line with check valve
on most air-air heat pumps
airflow must be reduced over the indoor coil during the heat mode
during the heating mode, the refrigerant in the indoor coil is under
high pressure
the use of a scroll type compressor on a heat pump can eliminate the need for a
suction line accumulator
the slide valve and piston in the reversing valve is actuated by pressure directed through the
solenoid and pilot valve
refrigerant flow through the compressor
is always the same regardless of operating mode
heat pump system, operating at 45 degrees ambient, may be ______ efficient than electric resistance heat
3 to 4 times more
what 3 things happen on most air-to-air heat pumps during defrost?
the reversing valve must switch to cooling mode, the outdoor fan shuts off and auxiliary heat is energized
a heat pump operates satisfactory in the cooling mode, but not the heat mode. this could be caused by
a stuck check valve or clogged txv screen
during the heating cycle, the outdoor coil becomes
an evaporator
because of the possibility of liquid floodback, a heat pump that uses a reciprocating compressor should be equipped with a
suction accumulator
since electric resistance heat provides 1 watt of useable heat for each watt of energy purchased, electric heat has a COP of
1 to 1
the preferred method to perform adjustments to the refrigerant charge in a heat pump system is in the _____ mode
cooling
it is not always a good idea to immediately connect a standard gauge manifold set and hoses to a heat pump when a problem is suspected because
the charge is critical, sometimes 1/2 ounce refrigerant
during the cooling cycle, the indoor coil becomes
an evaporator
a scroll type compressor
is less susceptible to damage from liquid floodback
as outside ambient air temperature decreases, a heat pumps COP
decreases
a customer complains that their heat pump system blows cool air periodically during the heat mode. this could be caused by
a faulty defrost relay ( does not energize the aux heat during the defrost cycle
when a heat pump is in the heating mode, what can cause frost accumulation on the outdoor coil when the ambient temperature is 45 degrees
the outdoor coil is colder than the ambient air
the indoor fan on a heat pump system operates
anytime there is a call for heating and cooling
the defrost cycle can be initiated by
time and temperature
the defrost cycle can be terminated by
time/temperature
liquid line filter/driers that are used on heat pump systems
must be a bi-flow design if used without check valves