Where are the key locations where HVAC pressure thermometer is usually installed in the refrigeration system

In modern HVAC (heating, ventilation, and air conditioning) systems, HVAC pressure thermometer, as multifunctional instruments integrating pressure and temperature measurement functions, are widely used in various refrigeration systems. Their installation location directly impacts the refrigeration system's operating efficiency, troubleshooting capabilities, and ease of maintenance. Proper selection and placement of HVAC pressure thermometer is crucial for safe and efficient system operation.

Compressor Suction Side (Low-Pressure End)
The compressor suction side is one of the most critical monitoring points in the refrigeration system. A pressure thermometer here provides real-time monitoring of the low-pressure refrigerant leaving the evaporator. By reading the pressure and temperature at this location, the refrigerant's evaporation temperature can be estimated, determining the evaporator's heat transfer efficiency and refrigerant availability.
During system commissioning, technicians often use readings at this location to determine whether the system is experiencing overheating, fluorine deficiency, or incomplete evaporation. It is the primary data source for system diagnostics.

Compressor Discharge Side (High-Pressure End)
The compressor discharge side is typically one of the areas with the highest pressure and temperature. Installing a pressure thermometer here helps monitor the system's condensing pressure and temperature. This data allows technicians to determine whether the condenser's heat exchange is performing properly and whether there are issues such as incomplete condensation, condenser fan failure, or insufficient cooling water.

In addition, the high-pressure side reading is crucial for setting the compressor protection system and can provide a basis for the high-pressure alarm setpoint.

Evaporator Inlet/Outlet
Installing pressure and thermometers at both the evaporator inlet and outlet can assess the evaporator's heat exchange performance. Comparing the inlet and outlet pressures with the temperature can determine whether the evaporator is clogged, frosted, or experiencing low evaporation efficiency. This reading is particularly important for large industrial cooling systems and chillers.

In addition, the pressure and temperature readings at the evaporator outlet are key parameters for calculating system superheat and help control the operating status of the expansion valve.

Condenser Inlet/Outlet
The condenser inlet and outlet are also important locations for installing pressure and thermometers. The high-temperature, high-pressure gaseous refrigerant at the condenser inlet should rapidly release heat and condense into liquid form here. High outlet temperatures may indicate poor condenser heat dissipation, insufficient cooling medium flow, or reduced cooling fan efficiency. The temperature and pressure at the condenser outlet can also be used to determine whether the condensing subcooling is appropriate, helping to optimize throttling device adjustment.

Accumulator and Pre-Expansion Valve
As a component that stores high-pressure liquid refrigerant, the accumulator typically requires a pressure thermometer at its outlet (i.e., before it enters the expansion valve). This data is crucial for determining system charge status and subcooling.

In high-efficiency systems such as VRF systems and chillers, temperature and pressure control in the pre-accumulator section directly impacts the overall system's energy-saving operation and load regulation response.

Distributor and Pre-Branch Pipeline
In multi-split units, modular chiller systems, or zoned air conditioning systems, independent HVAC pressure thermometer are often installed on the multiple branch lines after the distributor. By comparing temperature and pressure changes in each branch, it is possible to quickly determine whether there are issues with uneven refrigerant distribution, pipe blockage, or local system failures.

This installation method facilitates more refined energy management and regional performance monitoring and is a common feature in building automation systems.

Near the thermostatic expansion valve (TXV) bulb installation point
Thermostatic expansion valve (TXV), a key component controlling the refrigerant flow to the evaporator, typically has a pressure thermometer installed near its bulb to assist in setting and verifying the accuracy of superheat control. This reading is particularly critical for systems requiring precise control of evaporating pressure and temperature, such as precision air conditioners and laboratory cooling equipment.

Return air main and oil return lines
Some large systems also install HVAC pressure thermometer on the compressor return air main or oil return line to monitor the system's oil return status and the efficiency of the oil-gas separator. This is crucial for maintaining compressor lubrication and extending equipment life.