The Importance of a Condensate Trap


Traps are essential components of steam piping systems, protecting against outdoor air reflux, odor, and insects entering. Learn the best info about Condensation Trap.

Thermodynamic traps feature a straightforward design that’s reliable and economical, plus an added feature: venting air at startup. This gives them an edge over fixed orifice condensate traps or inverted bucket traps, which have small openings or bleed holes for venting air at startup.

Trap Design

The design of a condensate trap should take into account both the equipment being drained and any conditions present while simultaneously being adequately sized to handle full-load steam discharge and flash steam. Otherwise, an excessively high resistance to flow could create a pressure drop and result in a water hammer (the sudden implosion of steam pockets within a pipeline or condensate pan).

The ideal mechanical steam trap must completely drain at saturation temperature and be capable of modulating between light and heavy loads with minimal water hammer. Furthermore, it must feature a rapid venting device for quick startup venting. Two main mechanical steam trap types include lever float and inverted bucket traps. Lever float traps feature an up/down moving sealed spherical float to regulate condensate flow while buoyancy controls valve position on inverted bucket traps.

A proper trap must have both a large collecting pocket and a cooling leg to store condensate until its discharge temperature. This feature is particularly crucial in heat exchangers that utilize large volumes of steam, such as shell and tube units with their bundle of tubes supported by shell supports; when steam flows around these supports and mixed with the condensate accumulation, it creates water hammer, which could potentially harm the pipes and shell itself.

An oft-made mistake when installing a P-Trap is failing to size its pipe appropriately. Pipe length should allow for optimal functioning without the water seal evaporating over time – an issue that has contributed significantly to system failures.

An effective trap requires a vent line with an opening after it and above the trip point of its condensate overflow switch and equipped with a valve to prevent siphoning – when air fills the trap instead of condensate. A properly sized vent also helps avoid airlocks or freeze-ups in subfreezing climates.


Your heating system produces a significant amount of condensate. Therefore, selecting a model capable of meeting its specific needs is of vital importance for its proper operation. Lochinvar Condensate Trap was specifically engineered to capture this condensation produced by your high-efficiency gas boiler and drain it away, safeguarding both home safety and preventing harmful gases from reentering the heating system, making it an essential piece of your heating equipment.

Condensate traps serve an essential purpose: they prevent combustion gases from seeping back into your heating system by maintaining a water seal in the drain line. Therefore, proper installation and maintenance are essential.

Dry P-traps waste energy by evaporating moisture, and they allow sewer gases into the heating system, potentially damaging ductwork, floors, drywall, and air conditioning equipment as well as leading to mold growth, mildew growth, and fungus growth. Furthermore, this problem could put your health at risk by allowing sewer odors and gases back up into your house and leading to mold growth and other forms of decay.

To prevent these issues, it’s wise to replace your dry P-trap with a properly maintained and adequately sized condensate trap that is easily accessible for maintenance purposes. Furthermore, installing drain lines that connect directly to a clean-out can reduce clogs as well as help identify problems early.

Mechanical traps work by sensing the density difference between steam and condensate, rising when condensate enters, which then raises its float and opens the valve when more condensate forms, closing when steam comes through, and opening again when new condensate documents. They feature corrosion-resistant stainless steel floats as they offer excellent resistance against temperature fluctuations and velocity/phase shifts compared with thermostatic or thermodynamic devices.

Pressure Rating

A trap must withstand both maximum discharge pressure (CDL) and system piping design, handling both heavy and light loads without the risk of steam lock, excessive water hammer levels, or pressure differences between its supply and discharge points. Furthermore, it must also tolerate different temperature environments.

When selecting a trap, considerations such as maximum temperature and pressure at the point of discharge and system piping design must be taken. Float drains are commonly chosen since they can operate under lower pressure levels with outstanding reliability; additionally, they often handle rapid changes in load, which makes them an excellent option for modulating systems.

Float drains are more resistant to pressure fluctuations than other forms of traps and can operate at lower temperatures and pressure ranges than others. However, they may still be damaged by a water hammer that is too heavy; to reduce damage risk to their bodies, they should be installed away from valves and pumps as much as possible.

Bimetallic floats may be vulnerable to shocks and vibrations yet are less prone to abrasion and corrosion than other trap bodies. As such, they’re an ideal choice for large, heavy traps that must withstand shocks or vibrations without incurring damage – ideal for applications requiring stability with vibration and shock effects.

Water hammers can damage inverted bucket traps and need frequent priming to clear away debris in their bucket. Unfortunately, their operation and maintenance can be expensive as their small hole for condensate outlets or their bleed hole for inverted bucket traps vent air slowly into the atmosphere, slowing system startup time and increasing energy waste.

Mechanical steam traps utilize a stainless steel float that rises and falls with condensate flows, opening and closing the web as necessary. They’re less sensitive to pressure and temperature fluctuations than other kinds of surprises, meaning that even under heavy loading conditions, they remain open entirely.


Condensate traps, drain lines, and pans are integral components of any compressed air system. Without them, process gas vapor could remain trapped in pipes, leading to corrosion of metal components of the system and musty odors within buildings. Over time, drain lines may become clogged with dirt, dust, bio-growth, or debris accumulation, and water may back up into the system and overflow out of its primary drain pan, potentially causing extensive damage to both equipment and buildings.

Establish a regular cleaning schedule to avoid clogged drain lines, keeping your system free of gunk and debris that could cause blockages in its course. By opting for pre-manufactured trap kits such as those offered by EZ Trap (pictured at right), you can also have peace of mind knowing your drainage system has been explicitly designed to work effectively.

Method #1 – Visual Inspection

A blocked air conditioning or heat pump condensate drain line can usually be identified visually by simply peering into the standpipe at the primary drain pan inlet. Most clogs occur here, making clearing simple with either a pipe cleaner or a plumbing snake. On larger pipe systems, however, insect nests, rodent nests, or debris could clog your line and require professional plumbing snake services to unclog.

Method #2 – Blowing Out the Trap with 30 PSI of Compressed Air Utilizing an Extended Tip

As soon as a clogged drain line is detected, taking steps such as opening an indoor service access cap or drain pan cover and using compressed air can be extremely helpful in clearing it away. Be careful when applying mindset at too high a pressure that it breaks or loosens any pipe connections; using flexible rubber tubes with extended tips may make this job more straightforward, but be wary not to exert too much force as this could cause them to separate or leak.

Once complete, add water to the indoor service access cap or drain pan and replace its caps. It is essential that every time you blow out a line, you take steps to ensure any air from passing through is stopped, as this could allow condensation to continue accumulating in the system and eventually lead to a clog in future years. Taking these measures and monitoring how well your system is operating will prevent potential future issues and ensure a proper plan.

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