Condensate Drains & Pumps Codes & Recommendations For HVAC ...

Condensate drains & pumps Codes & recommendations for HVAC Condensate Drainage

• POST a QUESTION or COMMENT about air conditioner or heat pump condensate drain installation, leaks, clogs, troubleshooting, repairs

A/C condensate drains & pumps: codes, installation, leaks, clogs, connections, troubleshooting & repair.

We discuss air conditioning, heat pump & condensing boiler or furnace condensate drain leaks, locations, causes, repairs. Air conditioning condensate drain clogging - how to de-clog the A/C condensate line or drain pump. Air Conditioning Condensate Handling defects lead to condensate spillage, leaks, mold.

Where should the air conditioner or heat pump condensate drain be connected - where are we permitted to dump condensate? Examples of Model Building Codes Condensate Disposal Regulations & Recommendations

Condensate leak health and safety concerns are reviewed.

Page to photo: improper connection of the AC condensate drain to a plumbing vent risks sewer gas leaks into the building air conditioning system.

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What are the Proper Locations for A/C or Heat Pump Condensate Disposal

This article discusses the inspection and repair or un-clogging of condensate disposal systems, including air conditioning, heat pump or condensing boiler/furnace condensate drains & condensate pumps, and their proper installation as part of our review of condensate piping, traps, drains, condensate pumps, and the detection and hazards of air conditioning system condensate leaks in buildings.

Carson Dunlop's sketch shows the proper locations for disposal of air conditioner or heat pump condensate.

Notice that one of the most common condensate disposal locations, connection to a plumbing stack vent pipe, is not recommended and is prohibited by building code in some jurisdictions.

Article Series Contents

• CONDENSATE DRAINS, CODES - this article
  • LOCATIONS for CONDENSATE DISPOSAL - proper locations
  • PLUMBING CODE for CONDENSATE DRAINS - code citations
• CONDENSATE DISPOSAL, IMPROPER
• CONDENSATE DRAIN CLEAN & DE-CLOG
• CONDENSATE DRAIN INSULATION REQUIREMENTS
• CONDENSATE DRAIN PAN CLEANING
• CONDENSATE RETURN PIPES, PUMPS, STEAM
• CONDENSING BOILER/FURNACE CONDENSATE DRAIN
• DIRECT VENTS / SIDE WALL VENTS

Plumbing Code Citation for Installation of Air Conditioning Condensate Drain Piping

Carson Dunlop Associates sketches (left) illustrate both acceptable and not-recommended locations for the discharge of an air conditioner or heat pump condensate drain line discharge.

Uniform Mechanical Code Section 310.0, 310.1 Condensate Disposal

Here is an excerpt from the Uniform Mechanical Code pertaining to the disposal of air conditioning condensate:

Condensate from air washers, air cooling coils, fuel-burning condensing appliances, the overflow from evaporative coolers and similar water supplied equipment or similar air conditioning equipment shall be collected and discharged to an approved plumbing fixture or disposal area.

If discharged into the drainage system equipment shall drain by means of an indirect waste pipe.

The waste pipe shall have a slope of not less than 1/8 inch per foot (10.5 mm/m) or one percent slope and shall be of approved corrosion-resistant material not smaller than the outlet size as required in either Section 310.3 or 310.4 below for air-cooling coils or condensing fuel-burning appliances, respectively.

Condensate or waste water shall not drain over a public way.

To clarify, an indirect waste pipe is something that is upstream of a trap. That means we cannot dump into anything downstream of a trap. That would include the main plumbing vent stack. -- [Thanks to Al Carson, Carson Dunlop Associates, Toronto]

ICC Model Building Code, Section 307: Condensate Disposal Regulations & Recommendations

Note: new in 2015 is the ICC IMC 307.2.5 & IRC M1411.3.3 Drain Line Maintenance code for 2015

The ICC, under "Drain Line Maintenance" requires that

Condensate drains shall be configured to permit the clearing of blockages and performance of maintenance without having to cut the line. - ICC IMC 307.2.5 & IRC M1411.3.3 Drain Line Maintenance code for 2015, original source: http://www.iccsafe.org/

Devices or methods for providing condensate drain cleaning or de-clogging are discussed in this companion

article: CONDENSATE DRAIN CLEAN & DE-CLOG

The following HVACR condensate disposal recommendations summary cites, paraphrases, & comments on the widely adopted 2006 ICC model building code section on condensate disposal, section 307 [7]

1. Requirement for a drainage system

For the two Types of Condensate: Fuel burning devices vs Evaporators & cooling coils

• 307.1 requires that liquid condensation from fuel burning appliances be collected and discharged "to an approved plumbing fixture or disposal area in accordance with the manufacturer's instructions"
• 307.2 requires a condensate drain system for appliances containing evaporators or cooling coils, conducted from the appliance drain pan to an approved destination

2. Types, sizes, slope of Condensate Drain Piping

• 307.1 Condensate drain piping must be corrosion resistant for condensate from fuel burning appliances. using "corrosion-resistant material" and sized "no smaller than the drain connection on the appliance"
• 307.2.2 Condensate drain piping materials can be "... cast iron, galvanized polybutylene, polyethylene, ABS, CPVC or PVC pipe or tubing"
• Piping shall be at least 3/4" in diameter and ... shall not decrease in size ... [throughout its run from the condensate drain pan to its final disposal destination - no constructions by diameter]
• Horizontal runs of condensate drain piping slope at least 1/8" per foot in the direction of discharge. There is also a requirement for "uniform slope" and "uniform alignment"

4. Acceptable Condensate Drainage Terminations

• 307.2: "... Condensate shall not discharge into a street, alley or other areas so as to cause a nuisance." [i.e. do not discharge HVACR condensate over a sidewalk

5. Requirements for a Backup Condensate Drain System & Backup Condensate Drain Options

• 307.2.3 A secondary condensate drain system is required not in every installation instance, but in every installation at which "where damage to any building components will occur as a result of overflow from the equipment drain pan or stoppage in the condensate drain piping". This backup condensate system requirement refers for example to an indoor air handler installed in an attic or in living space where leakage into the attic ceiling or onto a floor system could cause damage to the structure. Typical damage includes cosmetic leak stains, mold infections of wet drywall or insulation, structural damage from rot or inviting insect attack, and even, as one reader reports, unsafe collapse of a ceiling fan mounted below the leak area.
• 307.2.3 recommends any of the following methods for handling a backup condensate overflow protection system:
  • 1. An auxiliary drain pan with separate drain: an auxiliary condensate drain pan at least 1.5" deep and at least 3" larger than the length & width of the appliance beneath which it is placed, using corrosion-resistant material of adequate thickness (0.7mm galvanized metal or 1.6mm non-metallic e.g. plastic) with a separate drain installed under the equipment and discharged to a conspicuous point that will alert building occupants to a blocked primary condensate drain
  • 2. A separate or secondary condensate overflow drain line connected to the primary or OEM equipment's drain pan at a higher level than the main drain, and discharged as in 1. above.
  • 3. An auxiliary drain pan without a separate drain line but instead provided with a water-level detection device (a switch that senses the presence of water in the drain pan) conforming to UL 508. The water or condensate detection switch in the drainless condensate overflow pan is wired to shut down the equipment.
  • 4. A water detection device (UL 508) that will shut off the equipment in event of blockage of the primary condensate drain can be installed in any of several locations that in essence detect that the primary drain is backing up: in the primary condensate drain pan, in the primary condensate drain line, or in the condensate overflow drain line, positioned to detect and shut down the equipment before the primary drain pan would overflow.
  • An exception to this condensate backup or overflow protection requirement is made for fuel-fired appliances that already include features that automatically shut down the device should the condensate drain become blocked. This feature is found, for example, on some condensing heating boilers or furnaces.

6. Other requirements for a condensate water-level monitoring device

• Section 307.2.3.1 requires use of a water-level monitoring device to provide condensate overflow protection on equipment where there is no secondary condensate drain and no ability to install an auxiliary condensate drain pan. Quoting "This device shall shut off the equipment served in the event that the primary drain becomes restricted. Externally installed devices and devices installed in the drain line shall not be permitted."

7. Model building code requirements for a P-trap on the HVACR condensate drain system

Bottom line: The model building codes require a P-Trap on all plumbing waste lines that is connected to a sewer.

The model same model building codes contain these very minimal requirements for traps on condensate removal lines for HVAC equipment:

1. a trap shall be installed in accordance with the unit manufacturer's installation and operating instructions

2. the condensate drain line slope towards its final drainage point shall be at 1/8" per foot [or, of course greater, where vertical drains are used - Ed.]

OPINION: your local building code compliance inspector/officer is the final legal authority on HVAC condensate drain trap requirements.

• IMC 407.2.4, Traps, requires that "Condensate drains shall be trapped as required by the equipment or appliance manufacturer." We interpret this provision to defer to the equipment manufacturer's installation instructions.

Watch out: in our OPINION and as we discuss in these articles, while a trap on a condensate drain line, usually provided quite close to the condensate collection pan itself, can reduce the chances of sewer gases backing up from a condensate drain that has been connected to the building DWV vent piping (not a procedure we recommend), a conventional P-trap in the condensate drain will not protect against all sewer gas backup possibilities.

In particular, when an air conditioner is shut down for long periods of time (say during the heating season) it is common for the water condensate contents of the trap to dry out, thus losing protection against sewer gas leaks backing up through that system. Solutions often proposed are for a trap of sufficient depth that water in the trap will not evaporate sufficiently to lose the trap seal during periods when no condensate is being produced. Special trap product can also provide a seal against sewer gas back-drafting through a dry trap. See detail

at DRY PLUMBING TRAP CAUSE & PREVENTION

• Canadian CMC 310.3: condensate waste pipes must be made from materials designed to work with that type of condensate drainage.
• U.S. IMC 307.2. 2: an A/C condensate drain inside diameter should not be smaller than 3/4″ and should not be smaller than the drain pan outlet diameter. I certainly learned that the hard way.