System protection: Neutralizing condensate waste

By Phil Warren


The popularity of condensing technology in gas-fired water heaters and boilers has increased steadily, primarily because condensing water heaters and boilers offer significant efficiency gains over non-condensing models.

Condensing water heaters use a secondary heat exchanger to boost efficiency by capturing more heat from combustion gases as they escape up the flue. This secondary heat exchanger then preheats the incoming water on its way to the primary heat exchanger, increasing the unit’s efficiency. Capturing more heat from combustion gases lowers their temperature, necessarily creating condensate in the flue: an acid-water mixture that drips back into the water heater and through the secondary heat exchanger.

Allowing this mixture to drain through the plumbing system untreated creates serious corrosion and other problems. Condensate neutralization and removal are impactful measures to ensure proper system performance and protection of the drainage system in a building or residence.


Why neutralization is important

The smart, long-term solution is to neutralize
condensate waste’s acidic content using a condensate pump with a neutralizer before it enters any piping.

Discharge coming from high-efficiency, condensing water heaters or boilers should be treated with some sort of neutralization process. That’s the only way to protect plumbing from the potentially harmful side effects of the condensation process. Condensate tends to be acidic because of the chemical reaction caused by the heat of the gas burner. Indeed, the higher the efficiency rating, the higher the acid level in the water runoff. If this runoff is disposed of directly through a structure’s plumbing system, its piping could corrode or rust over time, necessitating costly repairs. In addition, pumping the waste outdoors or into sanitary sewers could contaminate the groundwater or degrade the local water infrastructure. For homes with septic tanks, condensate waste might also destroy the good bacteria that are essential to keeping the system operating properly.

The higher, frontend costs of high-efficiency equipment are typically justified by lower energy consumption and the resulting lower monthly fuel bills. But those savings could be wiped out, and then some, if the plumber must return in just a few years to tear out and redo all the plumbing.


What is the best way to remove condensate and neutralize?

Neutralization can be accomplished in several ways:

1) Manually, by cutting a bed of limestone into the floor where the condensing appliance is located, and letting the condensate drip into it.

2) Positioning a limestone-filled cartridge inside of the condensing unit to neutralize the water internally.

3) Hooking a neutralization kit — essentially, a piece of pipe filled with limestone — to the exterior of the condensing equipment and letting the condensate flow through it. However, a condensate pump coupled with a neutralizer is a more sophisticated neutralizing solution. The pump moves the condensate from the appliance through limestone granules in a tray before discharging it into the sewer or septic system. Why opt for a pump? In many residential and commercial applications, the condensate evacuation cannot always be done by gravity to an existing sewer line, usually because the application lacks conventional, below-floor drainage. In such cases, a condensate pump becomes essential.


How a 2-in-1 condensate pump works

Gravity feed inline HVAC neutralizer.

Condensate from the water heater or the boiler enters the system via two 1-in. inlets on the side condensate pump unit and a third inlet on top of the enclosure. This inflow automatically activates a float mechanism that, in turn, starts the motor whose spindle/shaft drives the impeller. The condensate is neutralized as it comes in contact with the neutralizer pellets in the tray before being pumped safely away through a 3/8-in. discharge line connected to the structure’s main drainage line and, ultimately, to a sanitary sewer or a septic tank.

Not all condensate requires neutralization, however. In these instances, drainage can be routed into a third inlet located on the top of the unit near the discharge line. This drainage bypasses the neutralizer pellets and moves directly to the pump impeller, where it is immediately discharged. When selecting a 2-in-1 system, consider a pump capable of serving multiple mechanical systems.

Neutralization with gravity feed
A gravity-feed, inline HVAC neutralizer can be installed alone when the application’s gravity fall is
sufficient for moving the neutralized condensate to the discharge line. It can also work with a pump
system when the condensate needs to be pumped into the sanitary line.


Major codes take notice

Adherence to codes and regulations is paramount to ensure the longevity and efficiency of plumbing and HVAC systems. One often overlooked, yet critical aspect is the neutralization of condensate. The National Plumbing Code of Canada specifies guidelines for the treatment of condensate in plumbing systems to protect infrastructure and prevent environmental harm.

Additionally, provinces across Canada may have specific regulations that cater to regional considerations and environmental sensitivities. The importance of condensate neutralization goes beyond mere regulatory; it contributes to the overall sustainability of buildings and minimizes the ecological footprint of HVAC systems.

To obtain the most accurate and current information on condensate neutralization requirements, refer to the latest edition of the National Building Code of Canada (NBCC) and relevant provincial or territorial building codes. The NBCC is typically adopted by each province and territory, and local amendments or additional requirements may be included in their specific codes. Additionally, contacting the local building department or authority in the area you are working in would be beneficial. Keep in mind that codes and regulations are subject to updates, and it’s crucial to stay informed about the latest revisions to ensure compliance with the most current standards.

Enforcement of the condensate-neutralization codes will likely increase, as the problem and its potential toll on plumbing systems become more widely recognized. But if you are a plumber who frequently installs condensing equipment, you should not wait, if only for the sake of your customers.

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