HVAC Refrigeration Evacuation | Technical Refrigeration - Why is it necessary to evacuate a refrigeration system before charging it with refrigerant? Because all systems are designed to operate without moisture or non-condensable gas in the system. If your air conditioner or heat pump was installed without a proper evacuation the system it will not function as designed and will likely fail prematurely. (more…)
Free Cooling Air Conditioning - I’m looking for a residential high-performance system that uses an air intake damper or a multistage (multi-zone) heating and a cooling system similar to what I found at Economizer Systems and HVAC Control?
Any suggestions? Answer…………… (more…)
Richard - Very nice site!- Dual Two-Stage Split System with a Dual Slab Coil - I have a question; my home was fitted out by the previous owner with a twinned system, and a thermostat (Totaline P374-1900) which was not designed to control discreet, paired units. I confirmed this with Totaline. The result is only one unit runs, and the second unit is never activated. It functions, but not automatically.
Condenser Coil Repair - A crane is used here to lift a new condenser coil to a rooftop. The old condenser coil was leaking and could no longer be repaired. The process involved recovering all the refrigerant from the Trane rooftop unit.
The rooftop unit was then partially disassembled and the old coil cut out from the system taking great care and planning to ensure the new coil could be retrofitted to the old refrigeration piping system.
Good planning and skilled HVAC techs make the jobs go smoothly and make the replacement seem easy especially to the customer. (more…)
York VAV Air Handlers | HVAC Zoning - This York air handling unit serves several VAV boxes and runs on a static pressure control set point determined by a DDC program. This program has a static pressure control setpoint and sends a signal to the variable frequency drive to speed up or slow down the blower to maintain the proper static pressure control setpoint. When the VAV boxes need more air the drive speeds the air handler blower up.
When the VAV boxes need little the drive slows the blower down. The VAV boxes are controlled by a thermostat in their respective zones.
Air Handler Blower Motor - All air handling units have a blower located inside the air handler cabinet. The air handler blower motor has a motor that drives it. Some air handling unit blowers are direct drive and some are belt driven.
Many light commercial and residential blowers are direct drive blower motors by the motor’s shaft while many commercial air handling units are belt driven by the blower motor and some sheaves attached to the blower motor shaft and the shaft attached to the blower wheel.
Some sheaves are adjustable and some are not. If the belt is slipping always change the belt first before adjusting the sheave. Adjusting the sheave can cause the unit to produce more or less than designed airflow. Sheaves are typically set by Testing and Balancing HVAC Technicians. (more…)
This photo shows the air handler blower compartment. This is how the air handler is opened when the blower needs service or repair. The evaporator coil is on top of the blower which makes this an upflow air handling unit. The supply air ductwork will be above the AHU. Since this air handler is installed in a closet then the ductwork is installed in the ceiling and makes this an ideal installation for AC since cool air falls. (more…)
Learning the Basics of HVAC - To understand air conditioning and heat pump applications you will need to study refrigeration. Both air conditioners and heat pumps use refrigeration to move heat. Air conditioners move heat outside in the summertime using the process of refrigeration. Furthermore, heat pumps move heat in both directions (to the inside in the winter and to the outside in the summer) using the principles of refrigeration. (more…)
Air Filter Maintenance for Air Conditioning and Heating - Changing filters is a basic first step of proper HVAC maintenance and is necessary to keep the system running tip-top. Dirty air conditioner filters inhibit proper air flow and decrease efficiency and comfort for your air conditioner and furnace. A good air filter maintenance program will help avoid typical maintenance issues associated with dirty filters. Filters are essential for keeping evaporator coils clean and free of debris and dust. This air filter maintenance is not important? Read what happened to this person for not changing their filters on a regular basis. Air Conditioner Causes Water Damage (more…)
The TXV or Thermostatic Expansion Valve is preferred over other refrigeration metering devices because it only allows a specified amount of refrigerant to flow based on demand. Any type of refrigeration metering device creates a pressure drop in the refrigerant and with a pressure drop of the refrigerant a temperature drop also occurs.
This temperature is necessary to drop the refrigerant down to temperature lower than ambient temperatures inside the structure being cooled. This allows the refrigerant to absorb the heat contained in the air passing over the evaporator coil. (more…)
