Check that the refrigerant charge is correct.
As you know, one of the best ways to ensure that your equipment is operating at its peak performance is to perform regularly scheduled maintenance inspections. However, most dehumidifiers seem to be neglected as far as regular maintenance goes.

These maintenance instructions are specific to any piece of refrigerant-based dehumidification equipment. However, dehumidifiers used in natatoriums and other extremely humid, corrosive environments will need maintenance more often than standard dehumidifiers.

Dehumidifiers for enclosed pool areas are also more expensive; therefore, regular maintenance is a good investment of time and energy.

Check that dampers open and close fully, without binding.


Air filters— Check and replace as necessary.

Fans and drives — Check for worn or loose belts; adjust or replace as necessary.

When it is necessary to replace one belt in a set, the entire set of belts should be replaced. When fan belts are replaced, they could be retightened 24 to 48 hours after they are put into service. Check that fan bearing and locking collar set screws are tight, and lubricate bearings using a high-quality lithium grease.

Compressor oil level — The ideal time for checking the oil level is after a period of operation, because then there will be the least amount of refrigerant mixed with the oil. The compressor should have been in operation at least 30 minutes, and the crankcase should feel warm or hot to the touch. During operation, the refrigerant will be pumped out of the oil until only the normal quantity remains. The compressor is equipped with an oil sight glass. The oil level in the compressor is correct when liquid oil can be seen in the sight glass between the bottom and two-thirds full.

Check that the fan bearing and locking collar set screws are tight.
Refrigeration charge— Check the refrigerant sight glasses. When the refrigerant charge is correct, there should be no bubbles in the sight glasses.

Condensate line — Check that the line is free from obstructions. Always keep the condensate trap and lines free and clear. A dehumidification system for an indoor pool is capable of producing up to 25 gallons of condensate per hour.

Unit interior/exterior — Check for torn insulation and repair if necessary. Check for scratches, nicks, rust, etc., and repaint promptly.

Log entries — Check and record in the logbook the following actual operating values and the values read from the computer display:

  • Space temperature;

  • Space RH;

  • Pool water temperature; and

  • Pool water pH.

    Damper operation — Check that the dampers open and close fully without binding.

    Lubricate the bearings using a high-quality lithium grease.


    Annual maintenance should include all items listed under “Monthly Maintenance,” in addition to the following.

    Compressor and refrigerant system — The compressor and refrigerant system should be inspected annually by a qualified service technician. As a minimum, the following items should be done:

  • Change and inspect the refrigerant filter-drier.

  • Perform a complete unit operation test, including log entries.

  • Inspect fan bearing and belts for excessive wear; replace if necessary.

  • Inspect the general refrigeration system for possible leaks, chafing between tubing, and other items detrimental to operation.

  • Check electrical connections for tightness, including the compressor electrical box.

  • Clean debris and dirt from drain pans.

    Goodrich is vice president of operations for PoolPak Inc., 3491 Industrial Drive, York, PA 17402; 800-959-7725; (website).

    Sidebar: Huge Dehumidifier Travels To Hong Kong Via Air

    YORK, PA — PoolPak Inc. recently filled an order for a dehumidifying unit that measured 24 by 8 by 6 feet for an application in the Far East. “This unit, which weighs about 10,000 pounds, normally has a production lead time of about 14 weeks and would be shipped to the Far East by container ship,” wrote Michael B. Larsen, director, International Development, PoolPak.

    “With the four weeks of ocean shipping time, plus a week to clear all the paperwork at the port of arrival, there would usually be about 18 weeks from the time the order was placed until final delivery of the equipment to the jobsite,” he stated.

    In this instance, however, the customer had a very tight construction schedule. The customer opted to have the unit shipped by air from Kennedy Airport, New York, NY, to Hong Kong to speed up the shipping time.

    According to Larsen, the box was over 21 feet long, 8.5 feet wide, and 6.25 feet high.

    “The size of the box calls for special handling and stowage arrangements to be made,” Larsen said. “We are, for example, not able to move a shipment of that size utilizing a passenger-type aircraft.” Instead, the manufacturer opted for all-freight air shipment, mainly to allow loading and unloading of the box, Larsen said.

    The dehumidifier left JFK Airport on June 22, made a scheduled stop in Singapore, and eventually arrived in Hong Kong June 25 local time.

    “Customs clearance of the shipment was performed while the aircraft was still en route to ensure the fastest possible release to the customer after the arrival into Hong Kong,” Larsen explained.

    The other shipping alternatives, he added, would have been to ship the box by ocean freight from either an East Coast port, or via Long Beach, CA, to Hong Kong. Transit time would have ranged from 23 to 32 days.

    Publication date: 08/12/2002