TM017 Rheem Air Sourced Heat Pump Service Instructions REV: C
Date of Issue: 5/11/05
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5
Refrigeration Terms and their Meaning
Sub Cooled Liquid
– A substance below its saturation temperature at a given pressure.
Super Heated Vapour
–
A substance above its boiling point at a given pressure.
Saturated Vapour
– A substance at its boiling point at a given pressure.
Latent Heat
– Hidden (invisible) heat removed or added to a substance that results in a
change of state (i.e. liquid to a vapour) without an increase or decrease in temperature.
Heat of Compression
– The additional heat added to a substance by the act of
compressing it.
Low Side
– Components and pipe work of a refrigeration system operating at low
pressure, generally considered to be the evaporator, suction line and accumulator.
High Side
– Components and pipe work of a refrigeration system operating at high
pressure, generally considered to be the condenser, discharge line, liquid receiver/filter
drier and compressor case where a rotary compressor is utilized.
Boil Off
– The action of a substance as it absorbs heat and changes state (evaporates)
from a liquid to a vapour (gas).
Give Up Heat
– The action of a substance as it releases heat and changes state
(condenses) from a vapour (gas) to a liquid.
Components and their Function
Temperature and Pressure Relief Valve
- A valve designed to provide automatic relief by
discharging water in case of excessive temperature, pressure or both.
Never fit a T&PR Valve with a pressure rating greater than that indicated on
the product-rating label.
Pressure Limiting Valve (P.L.V.)
- A valve that controls its outlet pressure to a
predetermined limit.
Outlet Delivery Tube (Dip Tube)
- A plastic tube installed in the hot water outlet of the
water heater cylinder to conduct water from the highest point to the outlet connection. It
also acts as a fitting liner.
Diffuser
- A plastic device installed in the cold water inlet of the water heater cylinder to
assist with stratification. It also acts as a fitting liner.
Fitting Liner
- A plastic tube installed in the cold-water inlet of the water heater to provide
protection against corrosion through the life of the water heater.
Anode (Sacrificial)
- A metal alloy electrode installed in the water heater cylinder that by
galvanic action protects the cylinder from corrosion.
Thermostat
- A device responsive to temperature that controls the supply of electrical
energy to the compressor, which results in the stored water being maintained at the
required temperature.
De-Ice Thermostat
- A device responsive to temperature that controls a solenoid to
perform de-icing of the evaporator in cold weather.