Archive for February, 2011

Balanced-Pressure Thermostatic Steam Traps

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Balanced-Pressure Thermostatic Steam Traps

As shown in Figure 10-21, the principal parts of a balanced-pressure thermostatic trap consist of a flexible bellows, a valve head, and a valve seat. The bellows is partially filled with a volatile fluid and hermetically sealed. The fluid sealed in the bellows has a pressure–temperature relationship that closely parallels, but is approximately 10°F below …

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Thermostatic Traps

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Thermostatic Traps

The operation of a thermostatic trap (see Figure 10-20) is based on the expansion or contraction of an element under the influence of heat or cold. Thermostatic traps are of the following two types: (1) those in which the discharge valve is operated by the relative expansion of metals and (2) those in which the …

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Float Traps

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Float Traps

A float trap (see Figure 10-19) is operated by the rise and fall of a float connected to a discharge valve. The change of condensation level in the trap determines the level of the float. When the trap is empty, the float is at its lowest position and the discharge valve is closed. As the …

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Installing Steam Traps

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The installation of steam traps requires the following modifications in the piping: 1. Install a long vertical drip and a strainer between the trap and the apparatus it drains. The vertical drip should be as long as the installation design will permit. Exception: Thermostatic traps in radiators, convectors, and pipe coils are attached directly to …

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Automatic Heat-Up

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Automatic Heat-Up

Select a steam trap with a pressure rating equal to or greater than the pressure in the steam supply main but with a capacity based on the estimated pressure at the trap inlet. The pressure at the inlet of the steam trap can be considerably less than the pressure in the steam supply main. If …

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Sizing Steam Traps

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Sizing Steam Traps

Selecting the correct size steam trap for a system is an important factor in its operational efficiency. For example, an oversized trap will operate less efficiently than a correctly sized one, and will tend to create abnormal back pressure. Moreover, the installation cost will be higher and the operational life expectancy will be reduced. Manufacturers …

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Steam Traps

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A steam trap is an automatic valve that opens to expel air and condensation from steam lines and closes to prevent the flow of steam. The functions of a steam trap are: • Remove (vent) air from the system so that steam can enter. (Air in the pipes will block the flow of steam into …

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Circulator Troubleshooting

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Circulator Troubleshooting

Hermetically sealed, self-lubricating pumps should never be oiled or lubricated. It is not only unnecessary, but could also damage the pump. Very little maintenance is required for these pumps. Sometimes the failure of a hot-water (hydronic) heating system to produce heat can be traced to a malfunctioning circulator (pump). Before attempting to repair or replace …

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Circulator Operation

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Circulator Operation

A hydronic system circulator is always filled with system fluid (water). As soon as the pump moves water out of its discharge port, it is immediately replaced by an equal volume of water entering through its inlet port. Remember, these are closed systems that are always completely filled with water. If the system is not …

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Circulator Installation

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Always follow the pump manufacturer’ s installation instructions. These instructions will accompany the pump or can be obtained from the pump manufacturer (often by going online and downloading the manual from their web site). Note Most circulator manufacturers recommend using their cast-iron models for circulating water in a hydronic space heating system and their bronze …

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