Hot Water Boiler Reset Control | Heating and Cooling

Hot Water Boiler Reset Control
Hot Water Boiler Reset Control - Richard, We are looking at replacing our boiler with a new hot water boiler. The HVAC contractor, I suppose he is the salesman for the HVAC contractor, is trying to sell us what he refers to as a reset control for our boiler. He tells us it will save us more money by making our boiler more efficient. I think I understand how it works but my wife is not entirely sure about it. Can you tell us what you think about a boiler reset control and how it works?

Thanks, and we have learned so much from High Performance HVAC. And keep up the good work.

Brent (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 exceed the setting on the pressure relief valve. Finally, this will cause the pressure relief valve to open and discharge water to relieve the pressure. (more…)

Boiler Components Controls – HVAC Hydronics

Boiler Components - ControlsBoiler Components Controls - All hot water boilers must have an expansion tank. Water expands when it is heated. There must be a place for it to expand so that the pressure in the boiler loop remains constant. Without a hot water boiler expansion tank, the pressures in the boiler loop system would vary wildly.

Most likely, the pressure will exceed the maximum pressures designed for the boiler hot water loop system. This will result in setting off the pressure relief valve. (more…)

Domestic Hot Water Mixing Valve and Domestic Storage 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 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…)

Hot Water Boiler Economizer PreHeater | Energy Efficiency

Hot Water Boiler Economizer PreHeaterHot 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…)

Boiler Piping Plant Renovation | HVAC Hydronics

Boiler Piping Plant Renovation
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 heating to a large building or community.

In this case, new boilers were installed to replace the old inefficient boilers. The piping was rearranged and a hot water boiler economizer preheater added to make efficiency better. New controls were added for remote monitoring and control and to improve efficiency. Lastly, the entire plant got a makeover to make things more reliable, efficient, and modern. (more…)

HVAC Piping Valves | Heating and Cooling Hydronics

HVAC Piping Valves | Heating and Cooling Hydronics - Automatic Flow Valve

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…)

Hot Water Boiler Piping Zone Valves

Hot Water Boiler Piping Zone Valves
Hot Water Boiler Piping Zone Valves - Boiler piping zone valves are used for zoning hot water systems where multiple zones are needed. Hot water system zoning can also reduce energy cost because hot water heat zones which are not needed can be shut down thereby reducing boiler runtime to provide hot water heat for those specific zones.

Zoning a hot water boiler system can be done by using these zone valves and separate thermostats for each zone. The boiler piping loop is separated using zone valves on a manifold type system with each zone originating at the manifold. The manifold is piped directly to the boiler. (more…)

Aquastat Temperature Control | Boiler Components

Boiler Aquastat Temperature Control

Aquastat is the gray box on the left while the circulator is the black pump on the right.

Aquastat Temperature Control - The boiler aquastat controls the temperature of the water inside the boiler jacket. The boiler aquastat is a device to a boiler like a thermostat is to an air conditioner, heat pump, or gas/oil furnace. A boiler aquastat controls the temperature inside the boiler just as the thermostat controls the temperature for an air conditioner or heat pump.

The boiler aquastat will turn the burners on and off and also controls the circulator pump on a hot water boiler system.
(more…)