HVAC Products Containing Mercury and Proper Disposal – Mercury is extremely harmful to the environment and cause severe health problems in humans and animals. For many years HVAC and HVAC Controls manufacturers have used mercury in switches. Mercury is a liquid metal and provides a good source used in many switches because of its fluidity and conductivity. From thermostats to boiler controls the liquid metal provides a reliable and efficient switching mechanism to start and stop certain sequences in HVAC applications. (more…)
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?
Boiler Circulator Pump – The boiler circulator pump induces the flow of hot water through the boiler and the boiler loop. Usually the boiler circulator pump is controlled by the aquastat however there are various levels of control that can be found that control pumps. One way is by the aquastat as mentioned above. Another way is by an end switch in a zone valve. A thermostat in a particular zone will call for heat and the thermostat calls for the zone valve to open. When the zone valve is fully open an end switch closes the circuit to energize the circulator pump. Typically, the circuit is a control circuit so when the end switch closes it closes the circuit for a relay to energize the circulator pump (more…)
Hot Water Boiler Expansion Tanks – HVAC Hydronics
Hot 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 – Hot Water Boiler Expansion Tanks
Boiler 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.
Domestic Hot Water Mixing Valve and Domestic Storage Tank
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 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 scolded by extremely hot water temperatures. Boiler loops generally work on a temperature of 180 degrees Fahrenheit and this temperature is too hot for human contact without scolding or seriously burning the skin. A mixing valve is used in the loop to maintain a safe temperature for human comfort. The hot water is mixed with cold water at the mixing valve and the result is the temperature dialed into the mixing control valve which has a range of 120 degrees to 140 degrees if used for domestic hot water applications. Other mixing valves can be purchased that will give a whole range of temperatures including mixing valves that can be controlled by PLCs or DDC to maintain specific temperature ranges for whatever the desired temperature is for the application. (more…)
Hot Water Boiler Economizer PreHeater | Energy Efficiency
This is a hot water economizer and is a big preheater for domestic hot water use. This boiler plant serves a large community for heating and domestic hot water use. Domestic hot water is used for showers, washing dishes, laundry, ect, ect, ect…. 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. This system saves money because it uses the exhaust gases from the boiler to pre-heat the city water supply which is normally 50 degrees Fahrenheit. The exhaust gases from the boiler would otherwise be vented to the atmosphere and would be considered wasted heat. (more…)
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.