What are the rules for condensate piping?

Author: Albertha Hoeger  |  Last update: Saturday, May 3, 2025

Condensate drains shall not directly connect to any plumbing drain, waste or vent pipe. Condensate drains shall not discharge into a plumbing fixture other than a floor sink, floor drain, trench drain, mop sink, hub drain, standpipe, utility sink or laundry sink.

What are the requirements for condensate pipes?

Internal condensate discharge pipework must be a minimum of 19mm ID (typically 22mm OD) plastic pipe or as per manufacturer's instructions and this should “fall” a minimum of 45mm per metre away from the boiler, taking the shortest practicable route to the termination point.

What is the code for condensate discharge?

307.2. 1.1 (IPC [M] 314.2. 1.1) Condensate Discharge.

Where do you run condensate drain lines?

Condensate lines should terminate in a location that allows for safe and effective drainage. This can include outdoor areas, a nearby floor drain, or a dedicated drain connected indirectly to your plumbing system to prevent contamination.

Where should a condensate pipe drain to?

Where an installer is fitting a new or replacement boiler, the condensate discharge pipe should be connected to an internal “gravity discharge point” such as an internal soil stack (preferred method), internal kitchen or bathroom waste pipe such as sink, basin, bath or shower waste.

Furnace Troubleshooting Condensate Piping

What are the rules for condensate drain lines?

Condensate drains shall not directly connect to any plumbing drain, waste or vent pipe. Condensate drains shall not discharge into a plumbing fixture other than a floor sink, floor drain, trench drain, mop sink, hub drain, standpipe, utility sink or laundry sink.

Should a condensate pipe go into the ground?

Your condensate pipe can terminate above or below ground. If above ground, however, you will have to have it lagged.

Can you run a condensate pipe into a waste pipe?

Waste Pipe

Secondly, you can run your condensate drain line into a waste pipe. Ensure that you follow all the necessary guidelines if you choose this option.

How far should condensate line be from house?

Air Conditioning System FAQs

How far from the foundation does the air conditioning condensate drain line have to be? The drain line must extend a minimum of 12" away from the foundation to prevent excess moisture from accumulating at the foundation.

What are the options for a condensate drain?

To prevent the unwanted collection of condensate water, it should be drained away by gravity through a drain pipe or hose. If gravity drainage is not possible, a condensate pump is used to automatically pump the condensate water to a drainage point or sewer drain.

How much water should come out of condensate pipe?

In general, the water will be released in 300ml increments, which is why you may hear gurgling noises every so often when running your gas boiler.

What is the proper termination for the primary condensate drain line?

The most popular areas we terminate condensate drain lines to is the side of the house and usually about six inches from the ground. And this can be in a planted area that is large enough to accept the amount of drainage, and soak down into the earth.

Can condensate go into the sewer?

Most jurisdictions will not allow condensate discharge in the sanitary sewer system. Disposing condensate into sewer systems creates hundreds of gallons of water that must be treated daily during hot summer months.

How far can you run a condensate pipe?

For other gas or oil boilers then external condensate runs must be kept to a maximum of 3 metres and must be insulated. It may also be advisable to increase the pipe diameter to 32mm. If pipework is not sufficiently sized and insulated, freezing of the condensate may occur.

Should water be coming out of condensate pipe?

Leaks with a constant flow rather than slow drip can mean a condensate pipe has become disconnected or punctured. If that's the case, it's important to get your HVAC system serviced as soon as possible to avoid additional problems including further damage to your house.

Do you need a trap on a condensate line?

The internal rails aid in returning the ball to the seat in case the variable speed fan is operating at a low flow and low negative pressure. Figure 1: Trap Required in Condensate Line If the condensate drain line is under negative pressure (e.g., upstream of blower as shown here) a trap is required.

What is the code requirement for a condensate drain?

The IMC dictates a 1% minimum pitch of the drain, equal to 1/8″ fall for every 12″ (foot) of horizontal run. In practice, it is safer to use 1/4″ of fall per foot to ensure proper drainage and provide some wiggle room for error.

Where should a condensate pipe be installed?

“When fitting a new or replacement boiler, the condensate discharge pipe should be connected to an internal 'gravity discharge point', such as an internal soil stack, internal kitchen or bathroom waste pipe such as sink, basin, bath or shower waste.

How far should a condensing unit be from a house?

How Much Space Do You Need Around an AC Condenser? Horizontally, the minimum clearance space for an air conditioning condenser is one foot, however, two to three feet is optimal. Vertically, the minimum space for an AC unit clearance from trees above is five feet.

What are the rules for condensate drains?

Condensate drains shall not directly connect to any plumbing drain, waste or vent pipe. Con- densate drains shall not discharge into a plumbing fixture other than a floor sink, floor drain, trench drain, mop sink, hub drain, standpipe, util- ity sink or laundry sink.

Can you use PEX pipe for condensate drain?

Use PVC or PEX piping with support sloped at 1% (1/8-inch per foot). such as clevis or swivel loop hangers. Use perforated metal strap hangers. prior to disposal into approved drain.

What is the best pipe for condensate drain?

The recommended material to use for a condensate system is stainless steel. However, understanding the cost limitations to an all stainless steel condensate system, there are other alternatives. Condensate piping should be at a minimum, schedule 80, carbon steel.

Does a condensate pipe need an air gap?

When a condensate pipe is terminated into a rain water downpipe it is important that an air break is installed between the appliance condensate outlet and the drain pipe connection.

What is the minimum slope for a condensate drain?

Condensate from cooling coils and evaporators shall be conveyed from the drain pan outlet to an approved place of disposal. Such piping shall maintain a minimum horizontal slope in the direction of discharge of not less than 1/8 unit vertical in 12 units horizontal (1-percent slope).

Should condensate line be full of water?

The drain pan and condensate drain line in an AC unit move residual water from the system to outside your home. If you have an AC drain pan full of water, it can lead to leaks, bacteria and algae buildup, and water damage. Leaks can also be a sign of future problems with other AC system components.

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