Hot Water Boiler

A firetube steel hot water boiler is a vital part of a building's central heating system. The following covers technical specifications, working pressure, design standards, checking procedures, and ideal prices for steel hot water boilers.

Hot Water Boiler Selecting Guide

In general, a hot water boiler or steel hot water boiler is used to supply the heating for a building by using the heat from the combustion of the burner and heat exchange between the absorption surfaces of thermal energy with the heat transfer fluid.  Regardless of capacity, dimensions, and working pressure, hot water boilers are also divided into "fire tube" and "water tube" types.

Considering the importance of heat exchange levels in hot water boilers, steel hot water boilers, and firetube steam, some manufacturers, in order to increase these heat exchange levels according to standard implementation methods and plans, also use the bottom surface of the boiler for water circulation and heat exchange. These boilers are called "Wet Back" boilers. Wet-back boilers have better performance and higher cost than "Dry Back" boilers in terms of construction cost and heat exchange efficiency.

Types of steel boilers

In general, steel boilers are divided into the following types in terms of design and application, working temperature, capacity, and working pressure.

Types of steel boilers, regardless of capacity, working pressure, and dimensions, are as follows:

• Firetube dry back flame steel hot water boiler
• Firetube 2-pass dry-back steel hot water boiler
• Firetube 3-pass dry-back steel hot water boiler
• Firetube 3-pass wet-back steel hot water boiler
• Firetube condensing steel hot water boiler
• Firetube Wetback 3-pass steel hot water boiler
• Firetube dry-back 3-pass steel hot water boiler
• Steel water tube boiler for power plant and industry
• Industrial hot oil steel boiler

Advantages of steel hot water boiler

Some advantages of steel hot water boilers are mentioned in the following:

• Thermal shock tolerance
• Higher efficiency than cast iron hot water boilers.
• Ability to produce steel boilers in very high capacities
• Ability to withstand high pressures (can be used in high-rise buildings)

Hot Water Boiler Steel Grade, Standard, and Construction Plan

According to generally accepted international standards in the construction of hot water boilers, the body (shell), burner or combustion chamber, and networks must be made of special alloy steels. The heat tanks must be in accordance with DIN 17MN4 or ASMEA516/ G70, and the boiler pipes or tubes, DIN ST 35.8 standard (seamless flame retardant pipes with the possibility of waltz or expandability).

Although using high-quality steels and refractory tubes alone cannot guarantee the performance, efficiency, and useful life of the boiler, it is necessary to build the boiler using approved plans and also defined and accepted methods of international standards.
This point is so important that the construction of hot water boilers without the use of documented and internationally approved plans, even assuming the use of the best steels and boiler production equipment, even by the most well-known boiler manufacturers, cannot be accepted in any way.

Another important point regarding the construction and production of a standard hot water boiler is how they connect the fire tube boiler to the tube plates at the front and back of the boiler. This connection must be made by the expand (waltz) method, except for the resistant pipes inside the sub-burner, which must be done according to the standard by the expand welding method and using special devices approved by ISAB for welding.

Which Hot Water Boiler Has the Most Efficiency and Longevity?

When choosing and ordering a hot water boiler needed for your project or industrial complex, be sure to pay attention to the following:

1. Compliance with the valid and recommended standards regarding the type of steel used in the body, furnace, and tubes.
2. Complying with all executive instructions in accordance with the construction plan of reputable and international brands in the field of hot water boiler construction.
3. Not relying on advertisements regarding the quality of products and choosing the type, capacity, and working pressure of the required boiler.

For example, the best choice of hot water boiler for a capacity higher than 600,000 kilocalories per hour or 600 kilos of steam per hour, three-pass full-wetback boilers with main and secondary furnaces made entirely of Corrugated and refractory tubes and completely spiral, has the highest efficiency and longevity in fire tube boilers.

The Difference between "Water Tube" & "Fire Tube" Hot Water Boilers

Here are the 3 main differences between a water tube boiler and a fire tube boiler:

1. In fire tube boilers, the flow of flame and smoke resulting from combustion transfers their heat to the water of the boiler by passing through the pipes and passages of the boiler. However, in water tube boilers (such as power plant boilers), the heat of the burners occupies the main space of the boiler, and the water inside the tubes is heated. It is also mentionable that the water tube boilers are produced in very large capacities.
2. The water tube boiler is one of the types of hot water boiler that is made to work at high pressures. These types of boilers (usually used in power plants) produce steam up to a temperature of 550°C and at a working pressure of more than 100 bar. However, the working pressure in fire tube boilers is a maximum of 30 bar. Firetube instead of fiber tube boilers have long steel tubes that the hot gases produced in their furnace pass through these tubes, and the water that needs to be converted into steam or hot water circulates them.
3. Fire tube boilers can be a better option when it comes to the cost of construction and maintenance than water tube boilers.

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The Effect of Corrugated Furnaces & Pipes on the Hot Water Boiler Efficiency

Nowadays, due to the importance of convection heat transfer in increasing the efficiency of boilers and water heaters, the use of techniques that can improve heat transfer has increased. Based on complete studies on increasing heat from the heat transfer method, known as V.H.T.E. (Vortex Heat Transfer Enhancement) and as the name implies, the basis of work in these methods is based on the creation of a vortex.

One of the widely used methods of the V.H.T.E. is the use of curved or corrugated furnaces and tubes (Spiral) in hot water boilers. Which works by producing more turbulence in the fluid flow that causes an increase in heat transfer, therefore, the efficiency of the boiler.

Research has shown that the heat transfer at the curves in the furnace and corrugated pipes has a very complex pattern. Still, in summary, the displacement heat transfer in the corrugated furnaces and pipes is almost five times the heat transfer in the normal ones.

Also, fully corrugated furnaces and tubes greatly increase the efficiency of the hot water boiler due to the curves, and as a result, the increase of the radiation heat transfer and the total increase of displacement heat transfer in the V.H.T.E method.

Estimating the Capacity of Required Boiler for Pools & Hot Tubs

In order to meet the approximate heating requirement of the swimming pool and hot tub water and add the calculated amount of heat to the capacity of the cast iron or steel boiler, the following formula is usually used.

In the above formula, the volume of the pool water is in (liters), and the temperature difference is in (degrees Celsius). Usually, the temperature difference of the water entering the pools (according to the 10-12 degree temperature of the water piping) is about 20°C, and the temperature difference of the water entering the hot tubs is considered to be about 30°C. These numbers should be included in the above formula as (ΔT).

Note: The amount of heating obtained from the above formula is suitable for indoor swimming pools and hot tubs, and for an outdoor pool, this number should be multiplied by 2.

Although the heating time of a swimming pool or hot tub does not follow any specific rule or standard and depends on many factors, such as the type of pool usage, on average, the water heating time in indoor pools is between 18 and 24 hours, in public pools between 48 and 72 hours, and in the hot tub between 4 and 8 hours.

The Challenge of Engineers and Facility Experts in Choosing Condensing Boilers

No doubt, condensing hot water boilers theoretically have high efficiency due to the possibility of absorbing latent heat in water vapor resulting from combustion. However, in order to achieve this efficiency, we need to reduce the temperature of the water returned to the boiler to a temperature lower than the dew point temperature as the main condition for the condensation function in the hot water boiler.

In fact, the condensing boiler works as condensation only in a certain range of the temperature of the heat carrier fluid. Unfortunately, in other cases, it works like a normal spa boiler in terms of efficiency.

In short, it can be said that despite the claim of 92 - 94% efficiency of condensing boilers, due to several technical and economic reasons that are sometimes and briefly mentioned below, the claim of this efficiency and economic efficiency faces serious challenges.

Low Water Return Temperature Challenge

Basically, condensing hot water boilers face a challenge called low return water temperature; according to curve number 1, in condensing boilers, to achieve 96% efficiency, the return water temperature of the boiler should be 90°F (about 50°C). With the temperature Return water of 55°C (about 130°F), the efficiency of the condensing boiler reaches 87%, which will be equal to the maximum efficiency of three-pass full wetback fire tube boilers with the main and secondary burners of all CORRUGATE type and spiral fire tubes. In England, more than 90% of condensing boilers have never operated in their condensing phase and are used in their non-condensing phase. In the meantime, the important question is, "What is the justification for building the world's largest condensing boiler?"

The presented curves only show the maximum efficiency values and the actual efficiency of condensing hot water boilers varies like other boilers in the range of A to G. At the same time. Currently, there is no standard in the country to conduct tests to determine the efficiency of hot water boilers by legal authorities. It does not exist, and the claimed efficiency is without conducting the relevant tests.

Apart from all the problems of repair, maintenance, provision of spare parts, creating problems in the design of the spa temperature back below 40°C and the high price of the condensing boilers, in the best conditions, their nominal efficiency is at most 6% higher than the fire tube three-pass full wetback spa boilers with the main and secondary burners will be entirely Corrugated accordion and spiral fire tubes.

Which does not have an economic justification with scientific and economic analysis. According to the authoritative "Guardian magazine", even in a country like England, despite the very high price of fuel, It has not been able to justify its high price economically, and consumers have complained about the lack of cost reduction despite the high initial cost of these devices.

For more information about the efficiency and operating conditions of condensing boilers, you can refer to the article "Challenges of Condensing Spa Boiler Performance" in the articles section of the DamaTajhiz HVAC website.

Factors to Consider When Buying a Hot Water Boiler

Here are some important factors in order to get the most out of a hot water boiler:

Operation Failure Possibilities

Considering the importance of the boiler and burner as the heart of the central heating system of the buildings and the need to consider the possibility of defects and failures in their operation (in the long term) as well as the possibility of saving as much fuel as possible, if the number of residential units in the building is 8 units or more, or the total surface area of the building's useful basement is more than 1000 square meters, according to the installation standards, it is recommended to install two steel hot water boilers, each capable of providing 60% of the required heating capacity of the entire building.

Required Number of Boilers in Public Buildings

In important public buildings such as hospitals, hotels, etc., regardless of the type of boiler selected (cast iron or steel), for the central heating system, according to the recommendation of international engineering standards, 3 boilers are required, each with The power to supply 75% of the building's heating needs should be installed so that in case of damage or causing any problems for the burners or boilers, even one boiler alone is able to provide a major part of the heating needs.

Engine Room Standards

Also, considering the importance of the engine room as the provider of cooling and heating, it is recommended that the location of the engine room should be considered in such a way that, in addition to the possibility of easy transport, it has a large entrance door for the possibility of carrying various equipment. Having the appropriate size and area to facilitate installation, inspection, and possible repairs, as well as having sufficient light and proper ventilation.

Other Important Factors

• The most important difference between a hot water boiler and a hot water boiler is the high working pressure of hot water boilers.
• Before choosing any type of fire tube steel hot water boiler, check its dimensions and weight for entering and installing in the engine room.
• When choosing a steel hot water boiler, in addition to the capacity and dimensions of the hot water boiler, also check the required working pressure of the boiler, and if needed, you can contact the experts of DamaTajhiz HVAC Group.

After choosing the desired hot water boiler and before transportation, the foundation should be leveled at the place of installation of the boilers and executed with suitable dimensions. So that after transportation, the boiler can be placed directly on the corresponding foundation in the engine room.

Things to Consider When Installing a Hot Water Boiler

Here are the 5 most important factors you best consider when installing a hot water boiler:

1. In engine rooms where a steel or cast iron hot water boiler is used, it is necessary to install a water softener and/or deposit filter.
2. Considering that the installation of all the main equipment of the engine room, including the central heating boiler, is done on the pre-made concrete foundation with suitable dimensions according to the location plan and exactly where the equipment is located. Therefore, before installing the main equipment of the engine room, install the required concrete foundation according to the defined dimensions and standards.
3. Installing a manometer thermometer on the housing to show the temperature of the hot water in the boiler, as well as the pressure of the heating system, is mandatory on every steel hot water boiler.
4. Installation of a submerged thermostat (Augusta Smart Thermostat) with a temperature range of 30°C to 90°C (30°F to 110°F) is required to adjust the boiler temperature and the off-on command to the burner relay on every hot water boiler.
5. Also, install at least one safety valve and at least one submersible thermostat (submerged Augusta) with a temperature range of 30 to 160 degrees Celsius or more (based on the operating temperature of the hot water or hot water boiler) to adjust the boiler temperature and the off-on command to the burner relay. Warm water or hot water is required on every pot.

How to Increase the Lifespan of a Hot Water Boiler

Keep in mind these 11 factors so you can increase the life of your steel or cast iron hot water boiler:

1. Boiler design and construction based on approved construction plans, as well as the executive instructions and accepted methods provided by international standards.
2. The use of steels and standard refractory tubes, the sufficient heat level of the tubes, the number of passes of the hot water boiler, and the waltzing of the tubes instead of welding in the connection to the tubes and plates.
3. Use a resin water softener suitable for the volume of water circulating in the heating system, as well as a scale remover on the engine room pipes in a sufficient number and size.
4. Headhole, handhole, and manhole Installation of handhole valves with suitable dimensions and in the required places for the possibility of periodic inspections and services and even the possibility of replacing the damaged.
5. The quality of auxiliary equipment of hot water boilers is of particular importance, so the type and quality of auxiliary equipment used in hot water boilers have a significant impact on the performance, safety, lifespan, and efficiency of these boilers. Also, in order to compensate for the loss of combustion efficiency of the burners, it is necessary to choose the nominal capacity of the burner about 20% more than the boiler capacity.
6. Choosing the right number and capacity of the boiler so that even on the coldest days of the year, the central heating boiler is not required to work continuously and without interruption. (For example, in sensitive public service buildings such as hospitals, hotels, government centers, and large residential complexes, it is necessary to have multiple boilers so that there is always a hot water boiler ready to work).
7. Choosing a burner with a calculated capacity suitable for the boiler (up to 20% more than the capacity of a steel hot water boiler).
8. Adjustment of the burner flame (burning blue and direct longitudinal flow of the burner flame in the hot water boiler).
9. Carrying out periodic inspections and services, especially in relation to how the burner ignites in the hot water boiler, the correct operation of the level controls, safety valves, thermostats, etc.
10. If a diesel burner is in operation, the type and angle of fuel injection from the diesel burner nozzle are determined based on the diameter and length of the combustion chamber of the boiler and according to the suggestion of the boiler manufacturer.
11. Accurate calculation and implementation of the chimney in terms of diameter and according to the volume of combustion air.

Buying a Hot Water Boiler

One of the most important points in the design and production of steel hot water boilers (in addition to the compliance of all construction parts, parts, and equipment, control, access, testing, etc.) is the compliance and approval of the construction of each boiler with the executive plans and instructions for the construction of the boilers from internationally recognized and reputable brands.

In order to choose the most suitable hot water boiler, you must first determine the capacity, working pressure, and other required features of the boiler. On the website of DamaTajhiz HVAC, technical information of dozens of models of steel hot water boilers from reputed brands and with their main guarantee has been presented in order for you to enjoy the good feeling of an optimal and smart purchase.

The Price of a Hot Water Boiler

Choose and examine all types of hot water boilers at the best price only on the DamaTajhiz HVAC website. The price of hot water boilers varies according to the variety of models and brands.

Dear Users

While thanking you for your trust in the technical opinions of the heating equipment sales experts, it should be noted that the choice of the desired product brand is based on the capacity, working pressure of the boiler, standard plate, history, brand strength, service, and product price is ultimately determined by the buyer. But in the hot water boiler, most of the users and buyers choose and buy the best-selling brands such as Hararat Gostar, Packman, Garma Gostar, Azar Dama Gostar, and Azaran Sanat Emertat due to their quality, price, and after-sales service.

If, after reading the above material, you have more questions about deciding to buy different types of hot water boilers, diatomaceous and hot water boilers, you can contact the heating equipment sales experts at extension numbers 107 - 108 - 121 - 122. Get cast iron boiler advice and ask your questions.

Because the specialized group of DamaTajhiz HVAC Group provides all kinds of hot water boilers in the Middle East region, if you need a hot water boiler for any of the countries in the region, you can place your purchase order with confidence, product guarantee, and reasonable price. Please leave it to our sales experts.

"Buy with confidence and peace of mind from DamaTajhiz."

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