by High Performance HVAC | Air Handlers |
Air Handler Water Coil Freeze Stat - The HVAC Air Handler Freeze Stat is a low-temperature limit control and it is used mainly in commercial systems in the ductwork on economizers or in air handlers just before any coil especially water coils. It is a safety and protection control to prevent extremely cold air from reaching the hot water or chilled water coils inside the air handler where the air enters from the economizer.
Under ideal control setup if the freeze stat trips the economizer dampers close and the blower fan stops. This prevents coils from freezing. A frozen coil can bust open and will need to be replaced if it freezes. This is the purpose of the freeze stat in HVAC air handler applications which utilize economizers for free cooling and other purposes.
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by High Performance HVAC | Commercial HVAC |
Air Management in Hydronic Piping Loops - This is a secondary chilled water pump in a large pump room designated for pumps and piping in a data center. After a few minor tweaks and corrections, these pumps all operated flawlessly. There were very few issues with the secondary pump start-ups.
Unlike the primary pumps where cavitation was encountered on the primary chilled water pumps and the condenser water pumps for the chiller. The diagnosis for the cavitation of the primary pumps and the condenser water pumps was that the loops were not properly purged. This caused those pumps to cavitate.
The secondary pumps, pictured here, did not have that problem. Kudos to the team that purged the loops on this side of the chilled water system.
That was an initial installation issue. It was also a lesson in priming the system to ensure all the air purged from the loop. After all, cavitation in the pumps can cause damage to the pumps. Even after the initial installation purge, it is important to ensure air does not build up in the water piping loop. To do this we need a few devices to help purge the air before it becomes a problem. This will prevent nuisance problems such as hydronic air block in branch circuits of the loop. It will also prevent any damage that may be caused by pump cavitation as a result of too much air in the system.
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by High Performance HVAC | Water Heaters |
Tankless Water Heater
All About Hot Water Heaters - I have been transformed into a believer in tankless water heater systems. A few years back, I moved to Ukraine for professional reasons. When I first arrived in Ukraine it took a while for me to adapt to the culture, language, services, and way they do things here. Power failures, water outages, and occasionally natural gas outages are quite frequent here although it is tolerable and a minor inconvenience. (more…)
by High Performance HVAC | Commercial HVAC |
Water Tower Pumps and Controls | Pumping Systems - Water towers maintain a ready limited supply of water for communities in the event the water main goes down. Many towers are used for emergency situations for the fire department to have water for fighting fires and for water fire suppression systems to have a supply of water for the emergency if it should arise. (more…)
by High Performance HVAC | Commercial HVAC |
Domestic Hot Water Mixing Valve and Domestic Storage Tank - This domestic hot water mixing valve offers a way to temper the hot water coming from a hydronic hot water loop and boiler. It is very important to maintain the appropriate and desirable temperatures of water used for domestic water use.
First, you want to maintain a safe temperature so people are not scalded by extremely hot water temperatures. Once the temperature is safe it needs to be reliable. Since the boilers operate or are on standby 24/7 - 365, the availability is there to reliably make domestic hot water on demand. (more…)
by High Performance HVAC | Commercial HVAC |
Hot Water Boiler Economizer PreHeater | Energy Efficiency - This is a hot water economizer and is a big preheater for domestic hot water use. This hot water boiler plant serves a large community for heating and domestic hot water use. Domestic hot water is used for showers, washing dishes, laundry, etc, etc, etc….
The cold water supply from the city is routed through the economizer to be pre-heated before it goes through a heat exchanger and then the hot water storage tank. (more…)
by High Performance HVAC | Gas Furnaces |
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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by High Performance HVAC | Technical Reference |
Grounding and Bonding Electrical Systems | NEC Code - National Electrical Code Article 250 is all about grounding and bonding as represented in this photo where electrical systems are grounded and bonded to the buildings steel structure.
There are many different rules in the NEC (National Electrical Code) pertaining to grounding and bonding because grounding and bonding are important for safety reasons. Electricity will take the path of least resistance so if there is a short in the system the grounding system will be the path for the electricity instead of the motor or load that experiences the short. (more…)
by High Performance HVAC | Technical Reference |
Automatic Flow Valve
HVAC Piping Valves | Heating and Cooling Hydronics - Triple Duty Valves are three valves in one as the name implies. Triple Duty Valves act as a check valve, balancing valve, and shut-off valve all in one valve.
From the smallest hydronic loops to the largest hydronic loops triple duty valves are very a popular selection for engineers when designing hydronic loops for chilled water and hot water applications. The triple-duty valve consists of a threaded stem attached to a disc. The disc has a spring that will allow the disc to open when the flow is induced throughout the loop. (more…)
by High Performance HVAC | Commercial HVAC |
Chilled Water Storage Tank | Critical Facilities - Data centers use redundant systems for back-ups in case of an emergency. An HVAC chilled water storage tank adds an extra layer of redundancy to the process so if the chilled water plants crash the chilled water storage tank or tanks will provide a small cushion of time to allow the operating engineers time to straighten things out or in a worst-case scenario allow time for the servers in the data center to be transferred to another data center and shut down. (more…)