VAV Air Handlers are ideal for providing zones in a commercial building. Office space typically has several offices and open areas that need to be conditioned for the comfort of the people working in those areas or offices. By installing VAV boxes and zoning the ductwork from those VAV boxes these areas and offices can be kept comfortable using a VAV air handler system. More on how VAV boxes work. (more…)
DDC Controlled Chilled Water Actuator
DDC Controlled Chilled Water Actuator | HVAC Automation. This chilled water actuator is attached to a valve which supplies chilled water to the air handling unit. The air handling has a chilled water coil. The actuator modulates the valve based on a set point inside the DDC program. If the program has trim and respond capabilities the set point will rise up and down based on demand. Demand from the VAV boxes or the HVAC zones. Most DDC controlled actuators work off of a DC volt or current signal. (more…)
Air Handler Components 3 - Hot water coils inside of air handler units combine a boiler system or a special capacity hot water heater and forced air to provide forced-air heating. The concept is simple and used a lot in commercial and some in residential.
Commercial systems almost exclusively use a boiler to provide hot water to the hot water coil inside the air handler unit while the residential systems use mainly special capacity hot water heaters to provide hot water to the hot water coil inside the air handler unit.
On a call for heat, a pump is energized to begin the circulation of hot water from the heating source to the coil. The air handler unit blower motor energizes and the air begins to move across the coil. Heat is exchanged from the hot water coil to the air and the air is delivered to its appropriate destination through the ductwork.
Condensing Unit Too Close to House - This condensing unit was too close to the house to effectively reject heat. It was a bad HVAC condensing unit installation job by the HVAC installers. A mechanical inspector rejected the final permit until the condensing unit was correctly installed.
It is recommended that condensing units have at least 2 feet of space so that they can effectively reject heat. It needs space to breathe and pull air into the coils so that there is a proper heat exchange taking place when it is running. On this air conditioner condensing unit there are four sides to the unit.
By installing the air conditioner condenser too close to the house the installer effectively reduced the capacity of this unit by nearly one-fourth which will cause problems with the unit in the way of higher head pressures and that will cost the homeowner more money in the long run.
Start Capacitors for HVAC Compressors - HVAC single-phase compressors always come hooked up to a run capacitor. This helps the compressor when it is running, however, very few HVAC compressors come with a start capacitor. Most HVAC technicians know HVAC compressors pull a lot of amps on startup. This large amperage draws on startup is referred to technically as locked rotor amps or inrush current. It can be as much as 40,000 watts or more of pure power to get an HVAC compressor started. (more…)
Pricing New Air Conditioner - We get emails on a regular basis asking us about prices. Prices for a new air conditioner, heat pump system, boilers, and other types of HVAC systems. This article addresses those questions and why it is nearly impossible to give anyone an estimate.
Estimates for new systems are nearly impossible through email or forum. Someone needs to first look at the house and other factors involved with giving someone a price. (more…)
Air Conditioner Condensation Problems - It is important for air conditioning preventive maintenance to be performed on your system to avoid problems. Condensation water leaking near the air handling unit can be avoided with proper air conditioning repair and preventive maintenance. Normally this is a very simple problem that can be fixed in less than 30 minutes. Here is a list of what can cause water around the outside of the air conditioning air handler unit.
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Gas Furnace with Drain Pipes to Drain the Condensation.
Furnace Water Leak Condensate Problem - Richard, My furnace is leaking water. It is summertime, so I am not using it for heat except for the blower fan which is hooked up to the air conditioner and the heat. I know the pipes from the outside units run into a box on top of the furnace. I think that is a part of the air conditioner. What can I do to fix the problem if you know what the problem is by my explanation here? Dan
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VAV Box Types Fan Powered and Shut Off VAV Boxes - When attempting to name the different types of VAV boxes we find there are different names given to VAV boxes by different people and we find that no one is on the same page when VAV boxes are definitively defined.
We have fan-powered VAV and non-fan-powered VAV’s and we have series and parallel VAV’s and we have VAV boxes with a hot deck and a cold deck that mixes and one of the last projects I worked on some of the VAV’s were referred to as shut-off vavs. Variable Air Volume Boxes (VAV Boxes) regulates airflow into zones using a primary air source from a VAV air handler.
Aside from the control aspect of VAV boxes, pneumatic, electric, electronic, or DDC, there are many different variations to VAV Boxes and we will attempt to define each type of VAV including offering a diagram of each type and matching it with a specific application. VAV boxes are simply an assembly of a damper, damper controls, and sometimes reheat such as electric heat strips or a hot water coil. VAV boxes get their primary air source from a central VAV air handler and then distribute air throughout a specific zone the VAV box controls.
