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Hints on choosing a good water heater
I. How to choose a residential water heater
There are now two kinds of residential water heaters on the market: one is gas water heater and another is electrical water heater. The gas water heater boasts the following types: direct vent, flue, power vent and equilibrium. With regard to different ways of water storage, electrical water heater has two types: storage and instantaneous.
Then, how to choose a satisfying water heater? The experts tell us that we must put price, safety, convenience, life, cost, after-sale services, and many other things into consideration.
The advantages of gas water heater are fast-heating, large venting and low price. The disadvantages are that: it cannot be installed in the bathroom and thus there will be a distance away from the spot for using water; there will be more cold water in the tube and then the temperature is hard to control and the furring must be cleaned timely and toxic gas is easily to be produced in using.
The advantages of electrical storage water heater are clean, hygeian, large venting. It needn't be installed separately from the bathroom and toxic gas will not be produced. What is more, the temperature is easily to be controlled and thermal efficiency is relatively high. It has three protection devices which ensures safety and prevent over pressure, overheat and creepage from happening. The disadvantage is the time for heating is relatively long.
Instantaneous electrical water heater is easy to be handled, time-saving and space-saving. The disadvantage is its requirement for circuitry load is quite demanding: it usually needs 30amp. ammeter and wires of 4 mm2 cross section. Therefore, it is not convenient for old houses and even the new buildings need to reconsider its wire distribution as to meet the requirement of electrical load. Worth mentioning, some customer bought such products of which power is lower than 4000W without knowing the truth may eventually find the water not very hot.
After viewing the above, you can choose the most suitable products according to you actual needs. However, in view of the current condition of western developed countries, the tendency is that electrical water heaters are replacing gas water heaters and this has aroused much attention. Now, with the improvement of people's living standard, the electrical storage water heaters are becoming first choice of many families in China.
From the prospects of the development of electrical water heaters, they are the leaders of the future water heater industry. One reason is that the price of gas is increased whereas the price of electricity lowered; another reason is that it is safe to use electrical water heaters and it is also very hygeian and clean. The domestic electrical water heater industry will turn on a fast developing tendency and its quality, level of techniques and standard of service are also improving. In the mean time, customers will also benefit a lot from low price.
II. Hints on choosing a good electrical storage water heater.
1. Classification of electrical storage water heaters
According to the outlet, electrical storage water heater has two types: closed type and opened type. Closed electrical water heater uses one or several valves in the outlet to control the quantity of water and to work under the pressure of tap water. The advantage of this kind is flexible installation, high outlet pressure and low lost of thermal efficiency. However, the disadvantage is that the tank will work under pressure. Therefore, thick materials are needed and then the cost of making will be high. The opened electrical water heater has an opened outlet and this water heater use a valve in inlet to control the quantity of water. This kind of water heater works under normal pressure, so the requirement of making tanks is low and the structure is relatively simple. Currently, most of the electrical water heaters are closed ones.
According to the ways of installation, electrical water heater has three types: horizontal wall mount, vertical wall mount and floor stand. Horizontal wall mount types are installed horizontally on the wall, so the requirement for the wall is rather demanding. They are suitable for water heaters which are smaller than 100 L; Vertical wall mount types are installed vertically on the wall, and the requirement for the wall is also demanding. They are suitable for water heaters which are smaller than 100 L; Floor stand type can be put on the firm ground vertically and is suitable for water heaters which are larger than 100L.
2. The choosing of capacity
The unit for water heaters' capacity is Liter (L) and larger capacities have more ability for producing hot waters. The common capacities in the current market are 10L, 15L, 40L, 50L, 60L, 80L, 100L and few factories can produce products larger than 100L. The big capacity water heaters that Shanghai OTT Electrical Co., Ltd. can produce now are 120L, 150L, 200L, 250L, 340L,450L etc. Customers can choose the capacity according to its function, number of family members and habit of using water. 10L-15L water heaters are generally used in kitchens for washing dishes, vegetables and in bathrooms for washing faces, cleaning teeth. Therefore, people always vividly describe them as kitchen pet. If used for bathing, it's better to choose capacities which are larger than 40L: 40-50L types are suitable for one person; 50-60L is suitable for two person; 80L-100L is suitable for 3 person; 120L or above is suitable for 3 person or above; if people are used to taking a bath in tub, then 150L or above is more suitable.
3. The choosing of power
The unit of power is Watt (W) or Kilowatt (Kw). The power normally refers to the power of the internal electrical heating element. The larger the power is, the more heat will be produced in unit time, the less the time for heating and the higher demand for the electricity load.
Currently, the common powers in the market are: 1000W, 1250W, 1500W, 2000W, 2500W, 3000W, etc. In order to meet the diversity needs of people, double power electrical water heater emerges from the market. There are several combinations for customers to choose from: 500W, 500W; 500W, 1000W; 1000W, 1000W; 1000W, 1500W. In using, people can choose to use one heating element or two heating elements according to their needs. The power of the water heater generally coordinates with its capacity and both them are fixed by manufactures during the production. Generally speaking, 10L to 15L water heaters should choose 1000W to 1250W; 40L to 80L should choose 1250W to 1500W and 100L or above should choose 2000W to 3000W. In choosing electrical water heater, users should understand the power of the electrical water heater. The power is mainly determined by the cross section of the ammeter and electricity wire of your family. The cross section of electricity wire used for 1500W water heaters or below should not shorter than 1.5mm2; for 2000W-3000W water heaters, not shorter than 2.5mm2. Meanwhile, people should put into consideration whether this wire is especially used by water heater or shared by other electricity appliances.
4. The choosing of key components
1) Tank
Tank is the core component of a water heater. It directly influences the safety, usage and life of a water heater. In choosing, users should check whether the steel of the tank is alloyed with titanium; whether it is thick enough, the welding craft is advanced and reliable, the quality of enamel is assured, and the enameling and sintering craft are advanced. The “OTT enamel tank” that Shanghai OTT Electrical Co., Ltd. produces boasts the following advantages:
· We use enamel alloy steel plate which contains titanium, the thickness of which is 3mm. With super strong anti-pressure ability, it has undergone 200,000 times of fatigue experiment and the explosion pressure is as high as 45Kgf/cm2.
· The round welding line takes up automatic gas-protected welding method and the vertical welding line takes up automatic hidden arc welding method as to ensure the reliability of welding.
· Before enameling, the tank has undergone two procedures: polishing and twice degreasing as to ensure good closeness.
· The enamel “OTT enamel tank” is provided by an American company which is the world biggest enamel provider—FERRO. The automatic spraying technique sprays the enamel uniformly onto the super strong degreased and polished special steel plate. Sintering under 900 oC, the enamel and steel completely integrate with each other which makes the standard of anti-corrosion, anti boiled water weightlessness, anti-fatigue and anti impact technique of “OTT enamel tank” reach the world top level.
2) Electrical heating element
The quality of heating element directly influences the safe use of the water heater. Therefore, besides the power of the heating element, it is also very important to care for the electric capability of the heating element in choosing. Shanghai OTT Electrical Co., Ltd. produces “heating element that separating water from electricity and preventing from heating without water” for its water heater, the material of which adopts imported “Incoloy 800” nickel-chromium. The anti-furring coating on the surface of which could prevent corrosion and furring better. Supposing it heating without water for 24 hours, its electrical performance data will still keep fixed. Particular screw thread connection makes it airtight and exchangeable. The magnesia powder and silicon filled in is to separate water and electricity utterly. The heating elements have been examined 100%. With insulating resistance of 1000M Ω, it could provide 500 times safety than national standard of 2M Ω. The 1800 Volt high tension testing insures you safe in using.
3) Anode magnesium rod (Magnesium rod)
Magnesium is the last metal in the list of electrochemistry. The high quality anode magnesium rod is chosen on the basis of Germanic DIN4753 standard and is 60% bigger than ordinary ones. Therefore, it effectively improves the performance of protecting the tank from corrosion.
4) The choosing of insulation layer
The insulation layer of a water heater directly influences its insulation ability. The most important factor that determines is the insulation material and the thickness of the insulation layer. The insulation materials commonly used now are asbestos, sponge, foam and polyurethane foaming. In these materials, the insulation ability of polyurethane foaming is the best, whereas foaming plastic is inferior to polyurethane foaming. For asbestos and sponge, they can only be used as secondary insulation materials because they can not joint very closely with water heaters.
OTT choose environmental protection non-fluorine polyurethane foaming insulation layer. Its American-imported high pressure integrated foaming facility makes super thick non-fluorine polyurethane foaming wholly and evenly under high pressure. It also keeps heat extremely well and still can supply hot water even if the power is cut for 48 hours.
5）The choosing of backflow-proof inlet device
In order to prevent the heating element from heating under external water supply cut-off, all the water heaters take up the backflow-proof inlet device. Currently, the device that most factories uses is non-return safety valve (usually called safety valve with heart) to realize this technique. But the problem of this technique is that: when the water heater works, some of the water may discharge from the heart of the value to the pipes because of the cold shrink and hot bulge of water. When the water discharges, it can easily cause resonance in some pipes of water heater and let out abnormal noises. What is more, the pressure release function may subject to failure because of furring and may increase the working pressure of the tanks and shorten the life of water heater.
The patent backflow-proof device (ZL 02 2 15723.9) of OTT electrical water heater is quite unique, it could not only exterminate hot water backflow, preventing the heating element from heating without water, but also prevent the abnormal noise and safety problems of non-return safety valve. These secure the safety as well as extending life of service of water heaters.
5. The choosing of control method
With regard to the temperature control, electrical water heater can be divided into three types: mechanical, digital indicator and intelligent computer-controlled.
1) Mechanical controlled
The main component of mechanical electric water heater's temperature control is thermostat with mechanical knob. The thermostat is usually composed of thermal probe, adjustable drive organ and a pair of electrical contacts. When the temperature of the probe rises, the medium (liquid or gas) in the probe expands. And by capillary, the drive system was enabled to let the electrical contracts to work. The operating temperature of the electrical contract can be adjusted or remain open all the time by adjustable drive organ.
The main advantages of the thermostat of the mechanical water heater are: the operating temperature can be adjusted successively in a certain range; the operation is rather simple and the price is relatively low and it is suitable for family use. The disadvantage is that it only one method to control temperature and can only realize one method: circulating heating.
OTT mechanical controlled electrical water heater is the first in China to introduce Germanic E.G.O. surface thermostat. This kind of thermostat is convenient to operate with high precision and safety.
2) Digital indicator controlled (SX)
Digital indicator controlled system is usually composed of digital plate, main control board, strong electrical plate and temperature sensor. Digital plate is used to display the information like current temperature, set temperature, error code and timing; the button and knob on the digital plate can also be used for operation set-up. Main control board is the core of the control system. It is used to control the processing of temperature information and carry out control of water heater's operation progress. Strong electrical plate is used to provide the necessary power supply the system needed, carrying out strong electricity driving and creepage inspection. Temperature sensor is used to collect the information of the temperature.
Digital indicator controlled electrical water heater has two modes of heating, i.e., circulating heating and timing heating. Its advantages are creepage protection, automatic failure inspection, automatic alarming, intuitionistic and clear temperature display and accurate temperature control. It is suitable for modern families that love fashionable things.
3) Intelligent Computer-Controlled
Digital indicator controlled system is usually composed of digital plate, main control board, strong electrical plate and temperature sensor. The LCD display screen on the digital plate is used for displaying the working mode, heating mode, current temperature, set temperature, set menu, time, timing, error code, etc. Operations can also be realized by the buttons on the board. Main control board is the core of the control system. It is used to control the processing of temperature information and carry out control of water heater's operation progress. Strong electrical plate is used to provide the necessary power supply the system needed, carrying out strong electricity driving and creepage inspection. Over-heating and normal temperature inspection sensors are used for collecting the information of temperature.
OTT intelligent computer-controlled electrical water heater has four heating modes: circulating heating, model heating, valley electricity heating and timing heating. Its advantages are creepage protection, seven kinds of automatic failure inspection, automatic alarming, four periods of timed heating, accurate temperature control intuitionistic and clear temperature display, wire control and telephone remote control. It is especially suitable for businessman and modern families that love fashionable things. |
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