Types of Boilers | HVAC Heating and Cooling

Types of Boilers

There are many different types of boilers in the boiler room today in a variety of heating applications. There are two main categories of boilers among the different boilers and those two categories are steam boilers and hot water boilers. Either of those categories can be fueled by oil, gas, or electric (although electric is uncommon for steam boilers). They have different designs and piping configurations as a steam boiler system is designed to turned the water into steam and uses gravity and pressure to deliver the heat and the hot water boiler systems are designed to simply make hot water to be circulated (by a circulator pump) through a piping system to provide heat. Typically, hot water boilers are more efficient than steam boilers for a few reasons. First, there is less heat loss throughout the hot water piping and the shell of the boiler because the hot water boiler operates at a lower temperature than the steam boiler. This means there is less heat loss throughout the entire boiler and piping system. Secondly, because the hot water boiler operates at a lower temperature, it requires less fuel or energy to convert into heat. What kind of boiler do you have in your boiler room?

Air Management in Hydronic Piping Loops

Air Management in Hot and Chilled Water Piping LoopsAir 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 was very little 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 and this caused those pumps to cavitate. The secondary pumps, pictured here, did not have that problem giving kudos to the team that purged the loops on this side of the chilled water system. (more…)

Hot Water Boiler Expansion Tanks – HVAC Hydronics

Hot Water Boiler Expansion Tanks – HVAC Hydronics

Hot Water Boiler Expansion Tanks - Boiler Expansion TanksHot Water Boiler Expansion Tanks – There are two types of expansion tanks used on hot water boiler systems. The steel expansion tank and the bladder type expansion tank. These expansion tanks are used to provide a cushion for the expansion of water when it is heated. Without this cushion of air the pressure in the boiler system would rise and exceed the setting on the pressure relief valve causing the pressure relief valve to open and discharge water to relieve the pressure. It is necessary to for an HVAC technician to understand how these expansion tanks work in order to properly troubleshoot hot water boiler problems which may occur as a result of an issue with an expansion tank. One of the first things to check on a hot water boiler system when the pressure relief valve discharges water excessively is the expansion tank.

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Boiler Components and Controls – HVAC Hydronics

Boiler Components and Controls – Hot Water Boiler Expansion Tanks

Boiler Components and ControlsBoiler Components and Controls – All hot water boilers must have an expansion tank. Water expands when it is heated and there must be a place for it to expand to so that the pressure in the boiler loop system remains constant. Without an expansion tank the pressures in the boiler loop system would vary wildly and most likely will exceed the maximum pressures designed for the boiler hot water loop system. This will result in setting off the pressure relief valve. There are two different types of expansion tanks that can be used on hot water boiler systems. The most modern is the bladder type expansion tank (see picture to the right). The other type of expansion tank is a basic cylinder or barrel looking tank that hangs from the ceiling or is located in the attic. These tanks need to be drained from time to time to make sure they are not full. If they fill up with water and have to be drained constantly there is a problem with your boiler that should be looked at by a boiler technician. The bladder type expansion tank does not need draining on a regular basis like the cylinder or barrel type tank.


Boiler Piping Plant Renovation | HVAC Hydronics

Boiler Piping Plant Renovation

Boiler Piping Plant Renovation | HVAC Hydronics

Boiler Piping Plant Renovation – Hot Water Boiler Piping for a commercial boiler application. Boiler project being renovated and getting all new DDC controls for optimum hydronic control and efficiency. Boilers are an excellent way of providing good hot water heat to a large building or community. Some people refer to them as furnaces, hot water heaters, hot water heating systems, or hot water heater but the proper name is to call them hot water boilers. Hot water gas boilers provide clean draftless hot water heat through pipes and piping systems which HVAC professionals refer to as hydronic piping. Typically, hot water heating systems use pumps or circulators to move the water through the hot water piping system. Hot water heat is considered to be a good source of draftless heat by the people who have these hot water heating systems installed in their homes and businesses. (more…)

HVAC Near Boiler Piping Components

HVAC Near Boiler Piping Components

HVAC Near Boiler Piping ComponentsHVAC Near Boiler Piping Components – HVAC near boiler piping is very important to a good hot boiler loop circulation of the water. Hot water loop piping is key to maintaining good water flow throughout the system. The placement of valves, the circulator pump, and other loop controls are generally installed near the boiler. In the photo one can see the circulator pump, the expansion tank, the flue that exhausts the gases from the combustion process, an automatic air vent just to the right of the hot water loop circulator pump, a PRV or pressure reducing valve where the boiler make-up water comes into the boiler, and some unidentifiable controls. These loop components make up the near boiler piping which is very important to a good installation. If the near boiler piping is not installed properly several problems can occur that will cause issues with the heat and efficiency of the heating system as a whole.


Boiler Systems and Installation | HVAC Heating

Boiler Systems and Installation

Boiler Systems and Boiler Installation – It is very important to get it right the first time!

Boiler Systems and Installation – Purchasing a boiler can be daunting for most people as many people do not understand boilers and do not know what certain components are with boiler systems. Typically they trust the installing contractor to outfit and install the boiler with all the proper boiler components including making recommendations for optional boiler components.  There are resources we can use to try to understand boiler components but overall this research or study will not make one an expert in boiler installation. We simply have to trust the boiler installer and the skills of the contractor.


Expansion Tank Water Level Valve | HVAC Heating & Cooling

expansion tank water level valveExpansion Tank Water Level Valve

Expansion Tank Water Level Valve – Airtrol Valves help maintain the proper level of water inside expansion tanks. The valve allows air and water to flow into the tank where the air level in the tank allows for a cushion for expansion and contraction of the water in the loop. Since liquids do not compression air is used as the compression medium in the expansion tank to allow the loop to expand and contract without setting off pressure relief valves. The B&G Airtrol Valve is used in compression type expansion tanks without a bladder in the tank. Bladder type expansion tanks work differently than compression type expansion tanks. The B&G Airtrol valve takes the guess work out of ensuring the expansion tank has the proper level water and air inside the expansion tank.

Expansion Tank Water Level Valve – Maintenance & Service

This valve makes it easier during a maintenance or service call to ensure the proper water level is inside the expansion tank. There are some expansion tanks such as the one above, that do not have bladders nor do they have this Airtrol valve so the maintenance or service technician have to guess how much water should be in the expansion tank. Since bladder tanks do not need this feature bladder type expansion tanks would not have this valve as bladder type expansion tanks use a bladder and air pressure to maintain proper levels inside the tank. Bladder expansion tanks are always filled to capacity whereas if a steel expansion tank (bladderless) is completely full there is no expansion in the system and problems occur if it becomes fully waterlogged. Therefore this valve is nearly a necessity to ensure proper levels in bladderless expansion tanks and to take the guess work out of the proper water level in the expansion tank.  You can learn more about hot water boiler expansion tanks here.

You can learn more about expansion tanks and HVAC here.


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Expansion Tank Water Level Valve

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