Maintaining Your Central Air Conditioning System: The Evaporator

The Evaporator

Air Conditioner Evaporator Coil

This is the second article in a 3 part series about “Maintaining your Central Air Conditioning System”. In the first blog post we talked about the Air Filter. Today we are going to discuss the Evaporator.

We do want to take a moment to point out that it is always best to have a seasoned professional perform your Air Conditioning maintenance as this is a complex and vital piece of your home. However, we do want to provide you with common information for DIY (Do It Yourself) tasks.

If you keep a clean filter in your system, your evaporating coil will stay clean much longer. However, it will still collect dirt over time. It is best to check these coils every year and clean them as necessary. The evaporator is usually found right above the furnace in the plenum (A plenum is any space used to move air for heating and air conditioning).

If the plenum has foil-wrapped insulation at its front, you can clean the evaporator. If not, do not try to clean it. Bid On My Job has seasoned professionals standing by to give you a quote on performing this task.

Assuming your plenum is foil wrapped, take the following steps to take to clean the evaporator:

  1. Disconnect the power to the air conditioner. You will find the circuit breaker to the unit inside your home’s electrical service panel.
  2. Remove the foil-wrapped insulation. You should find an access plate behind the insulation. Remove screws to lift off plate.
  3. Use a stiff brush to clean the bottom of the evaporator. The evaporator can be slid out if the brush can’t reach all the way to the back. Just be careful not to bend the pipes. Remember to be very careful when cleaning the delicate evaporator coils.
  4. The tray below the evaporator needs to be cleaned as well. To prevent the growth of fungus, you can place one tablespoon of bleach in the tray.
  5. Return the evaporator to its place, screw the plate back in, and tape the insulation back up.
  6. After you turn the air conditioner on again, check for air leaks. Seal any leaks with duct tape.

You can check out the first article in this series here: Maintaining The Filter

Up Next: The Condenser

7 thoughts on “Maintaining Your Central Air Conditioning System: The Evaporator
  1. Multiple Effect evaporator, water is boiled in a sequence of vessels, each held at a lower pressure than the last. Because the boiling point of water decreases as pressure decreases, the vapour boiled off in one vessel can be used to heat the next, and only the first vessel (at the highest pressure) requires an external source of heat. This is called multiple effect and no of stages / effects is depend on quantity of vessel / calendria in sequence. Theoretically, one kg of steam evaporates one kg of water. In multiple effect evaporator, one kg of steam evaporates up to 6kg of water by no of effects and vapour recirculation by thermo vapour recompressor. It is called as steam economy 1:6.

    Feed is preheated to nearby boiling temperature in Pre heater that connected with all calendria. All calendria are operated at stage by stage vacuum with reduced temperature. So feed is preheated by stage wise from lower temperature to higher. Then it is passed via first calendria tube bundles as fine film layer over the tube surface area. In shell side fresh Steam is given via Thermo Vapour Compressor. Feed is heated and evaporated in calendria. Evaporated Vapour is separated in Vapour Separator, vapour is sent to second calendria Shell side. Un evaporated feed is transferred to second calendria tube side. Here further evaporation is done. So each calendria evaporates feed and concentrate coming out from last calendria. In this system, concentration is achieved by stage by stage and each calendria have higher concentration as stage increases.

    A part of evaporated vapour is recycled to first calendria via thermo vapour recompressor. In Thermo Vapour Compressor, Fresh Steam with pressure is passed via steam nozzle. Steam produce high velocity and produce a venturi Effect. This will recirculation a part of evaporated vapour. By using Thermo Vapour compressor and multiple stages, steam economy up to 1:6 is achieved. This result depends on feed water quality.

    In last vapour separator, evaporated vapour is condensed by direct contact condenser or indirect contact condenser. In direct contact condenser, cooling water from cooling tower is sprayed in top and absorbs, condense vapour in to water. This will heat cooling water and returned to cooling tower to reduce temperature. In indirect contact condenser, vapour is condensed by cooling tower water by heat exchanger (shell & tube / Plate type). Non condensable gas from system is removed by water ring vacuum pump.

    We installed many falling film evaporator capacity up to 280KLD for various industries. Mainly falling film evaporator are suitable for handling reverse osmosis reject water and having more than 40,000mg/l TDS. This system evaporates up to 90% of feed and gives concentrate 300gram per litre. This concentrate is dried in drier / crystallized in crystallizer / or handled with forced circulation with pusher centrifuge.`

Leave a Reply to evaporatorseo Cancel reply