What Causes Fish Tank Heaters To Fail?

As the bimetallic strip bends toward and away from contact, an electric arc is created that eventually will pit and corrode the points. To prevent this, a condenser should be attached across the circuit, above the thermostat. Should the condenser short out, the current would bypass the thermostat, which would then not be operating. The heater, with no control on it, would continue to heat.

Better thermostats today have a fuse in series with the condenser. Should the condenser short out, the fuse will blow. The thermostat and heater, however, continue to function without the condenser and fuse assembly until they can be replaced.

Another cause of trouble is water in the thermostat tube. In this situation the heater continues to function but without any shut off control.
Occasionally, although not frequently, the silver points that are used today melt and fuse together. This prevents normal opening of the thermostat and is usually a possibility when the power source is direct current (D.C.). Cleaning the contact points occasionally with very fine sand paper will help correct this trouble.

The most common causes of heaters failing to heat is usually current failure, or improper contacts in the wall plugs. Occasionally the thermostat plug becomes disconnected without anyone realizing it. All that is necessary to restore its function, of course, is to plug it back in.Even more infrequent is a burned out heating oil, or a broken connection within the circuit itself.

Heaters fail to heat only a fraction of the number of times they overheat. It is hoped that the number of times the latter occurs will be lessened considerably by the use of proper fuses.

A magnetic snap action thermostat is a thermostat that operates on the same principle as the ordinary thermostat, but with the following addition. There is a small magnet at the end of the bimetal strip and a corresponding plate on the mounting. As the bending bimetal strip comes close, the magnetic attraction asserts itself, closing the contacts sharply with a snap—hence the name. This rapid closing eliminates the problem of the arc and the necessity for the installation of a radio condenser.

What is a vibrator pump for a tropical fish aquarium?

The same principle of make-and-break current operating in the common doorbell also applies in operating a rubber, leather, or plastic diaphragm which fits over the air chamber of the pump. As the diaphragm moves up and down, air is forced out through one-way valves.

Most diaphragm pumps have a low air pressure but an adequate air volume. They are usually equipped with a knob which controls the volume of air put out. Diaphragm pumps do not usually have so long a life as do cylinder pumps, nor are they so powerful. They are usually less expensive, and for the hobbyist with one or two small-to medium-sized tanks they are perfectly adequate. They have the advantage of no outside moving parts and do not give off any heat. Nor do they require any oiling or other care. Should they break down, it is usually necessary to return them to the manufacturer for repair. In many cases the guarantee specifies that opening the case voids the guarantee.

Another point of information about vibrator pumps: they must be placed on a firm yet resilient surface, not an unyielding one such as a wall, a table top, or a loose floor board. A sponge rubber pad makes an excellent mounting for a vibrator pump. Such material also helps to eliminate the hum which is an unfortunate feature of some vibrator pumps.

Some diaphragm pumps are very cheap, while others are comparatively expensive. In purchasing pumps, as with other items, you get what you pay for. The lower-priced pumps are not necessarily a better buy. Often they are cheap merchandise offered for sale at a low price. In order to compete, some manufacturers sacrifice quality and reliability so that they can offer a low price. Shop carefully before you purchase a pump, especially if you want it to provide long service. Consider only nationally advertised products.

Vibrator pumps require no care; cylinder pumps should be oiled regularly. Some vibrator air pump features an adjustable output of air, allowing you to control exactly how much air is released.