HVAC
Condensate neutralizer field guide for condensing appliances
Condensing appliances make acidic condensate, so a neutralizer raises the pH with media before the drain. Size it, install it downstream of the trap, check the outlet pH, and refill the media.
Direct answer
A condensate neutralizer is a tube or chamber of media, usually calcium carbonate or magnesium oxide, that raises the pH of the acidic condensate a high-efficiency condensing furnace, boiler, or water heater produces before it reaches the drain. Many codes and manufacturers require it, especially on cast iron, concrete, or septic systems.
Key takeaways
- A condensate neutralizer is a tube or chamber of calcium carbonate or magnesium oxide media that raises acidic condensate pH before the drain.
- Condensing appliances (90 percent AFUE or higher, plastic vent) produce condensate around pH 3 to 4 on gas, lower on oil.
- Size the neutralizer at roughly 1 gallon of condensate per hour for every 100,000 Btu of input, plus contact time.
- Bring outlet pH up to at least pH 5, ideally 6 to 7, tested at the discharge while the appliance runs.
- Refill media once or twice a year; chips crust over and stop reacting before they visibly run out, so check pH not level.
What a condensate neutralizer is and why it exists
A condensate neutralizer is a tube or a chamber filled with media that raises the pH of acidic condensate before that water enters the drain. A high-efficiency condensing furnace, boiler, or tankless water heater pulls so much heat out of the flue gas that the water vapor in the exhaust condenses, and the liquid that comes off is a weak acid. Left alone it corrodes metal drains, etches concrete, and kills the bacteria in a septic field. The neutralizer is the small, dumb, mechanical fix that keeps the acid from doing that.
It is dumb on purpose. No pump, no power, no moving part, just media the acid flows through and slowly dissolves. That simplicity is also the trap. Because nothing fails loudly, the media exhausts, the acid passes straight through, and the drain corrodes for a year before anyone notices the white tube went quiet.
The condensate drain guide covers the trap, the slope, and the disposal for that line in full. This one is the acid side: why the water is acidic, how the neutralizer fixes it, how to size and install it, and the one maintenance task that keeps it working.
Why is condensate from a high-efficiency furnace acidic?
Condensate from a condensing appliance is acidic because the appliance is built to condense the flue gas, and the flue gas is full of combustion products that dissolve into that water as acids. A standard 80 percent furnace sends its exhaust up the flue hot and dry. A condensing furnace at 90 percent AFUE or higher pulls the flue gas below its dew point, roughly 130 degrees F, on purpose, because the heat released when the water vapor condenses is exactly the efficiency the high-AFUE rating is selling.
When that vapor condenses, carbon dioxide, nitrogen oxides, and traces of sulfur from the fuel dissolve into it and form carbonic, nitric, and a little sulfuric and sulfurous acid. On natural gas the result commonly runs around pH 3 to 4, acidic enough to be a problem and not something you argue with. The exact pH varies with the fuel, the combustion, and the appliance, so treat the 3-to-4 figure as the field range, not a spec.
Oil runs lower because the fuel carries more sulfur. The mechanism is the same. There is just more acid in the water.
Do you need a condensate neutralizer?
You need a neutralizer on any appliance that makes acidic condensate, which means any condensing appliance: a condensing furnace at 90 percent AFUE or above, a condensing or mod-con boiler, and a condensing tankless water heater. If the unit has a plastic vent, a PVC or CPVC flue out the sidewall instead of a metal flue up a chimney, it is a condensing unit and it makes acid. That plastic vent is the tell on a walkthrough.
Whether you must install one is a separate question, answered by the drain it discharges to and the code. The acid has to go somewhere, and what it lands on decides the stakes. Discharge onto a cast iron or galvanized drain, into a concrete floor sink, into a condensate pump, or into a septic system, and neutralization is doing real work and is often required. Discharge into a PVC line that runs straight to a municipal sewer with plenty of dilution, and the pipe itself shrugs the acid off, but the sewer authority may still want it neutralized.
The boiler types guide covers which boilers condense and why the return temperature decides it. If it condenses, plan for the acid.
What acidic condensate damages without a neutralizer
The acid attacks whatever it touches that is not plastic or stainless. Cast iron and galvanized drain pipe corrode from the inside, and a cast iron floor drain or a cast iron stack downstream of an untreated condensing furnace can rot through in a few years. Concrete is worse than people expect. Acidic condensate dripping on a concrete floor or running through a concrete trench etches and pits it, and over time it eats the surface down to aggregate.
Metal in the path takes it hardest. A standard condensate pump housing, its impeller, and its check valve corrode and seize, which is why a pump on a condensing appliance has to be acid-rated and the acid neutralized ahead of it. Floor drains, drain grates, and any metal fitting in the line are on the same list.
The appliance itself is built to survive this. A condensing furnace runs a stainless or aluminized secondary heat exchanger and a plastic flue precisely because the manufacturer knows the flue gas condenses to acid inside the box. The drain the installer adds downstream usually is not. That mismatch is the whole problem: the equipment is acid-rated and the drain it discharges to often is not, so the corrosion shows up in the building's plumbing, not in the unit.
PVC and ABS pipe handle the acid fine, so a unit draining through plastic straight to a sewer survives at the appliance. The damage moves downstream to whatever is not plastic, and to the environment. On a septic system the acid kills the bacteria the field relies on. The pipe at the furnace looks fine the whole time, which is how this gets missed.
How a neutralizer works
The neutralizer is a length of pipe or a small box packed with an alkaline media, and the acidic condensate trickles through it on the way to the drain. The acid reacts with the media, the media dissolves a little, and the water comes out the far end with its pH raised toward neutral. No power, no controls, just a chemical reaction between a weak acid and a basic solid.
The reaction is the whole device. Calcium carbonate, the main ingredient in limestone and marble, reacts with the acid and releases the calcium that buffers the pH up. Magnesium oxide does the same job through a different reaction and tends to drive the pH higher and faster. Either way the media is a consumable. It is being eaten by design, a little with every gallon, and when it is gone the device is an empty tube that does nothing.
The chemistry is forgiving in one useful way. Calcium carbonate is only mildly soluble, so it raises the pH toward neutral and then largely stops, which makes it hard to over-treat the water into something strongly basic. The reaction gives off carbon dioxide and dissolved calcium along with the buffered water, which is why spent media leaves a chalky scale. Magnesium oxide is more aggressive and can push the pH higher, so on a blended media the magnesium does the heavy lifting and the calcite keeps it in a sane range.
Contact is what makes it work. The water has to sit against the media long enough to react, so the media has to be deep enough and the flow slow enough that the condensate is not just rushing past. A neutralizer the water races through under-treats no matter how good the media is.
The neutralizing media: limestone, calcite, and magnesium oxide
Two materials do the actual work: calcium carbonate and magnesium oxide. Most off-the-shelf media is calcium carbonate in the form of limestone chips, marble chips, or refined calcite pellets. Buy media rated for the job, commonly 90 percent or more calcium carbonate, because cheap limestone and marble carry other minerals that do not dissolve and instead coat the chips.
That coating is the catch with plain limestone and marble. As the calcium carbonate reacts, the insoluble junk in the rock, plus an insoluble calcium salt the reaction itself leaves behind, builds a crust on the chips. The crust blocks the acid from reaching fresh media, and neutralization tails off even though the tube still looks full. This is why media gets replaced on a schedule and not just when it visibly runs out.
Magnesium oxide, often sold blended with calcite as pellets, reacts faster and holds the pH higher, which helps on more acidic condensate like an oil unit or a high-volume boiler. Mixed media is common for that reason. Match the media to the manufacturer's recommendation for the appliance, and refill with the same product so the sizing still holds.
Inline cartridge vs box and chamber neutralizers
Two shapes cover most installs. The inline type is a cartridge, a tube, or a canister that plumbs straight into the condensate line, small and easy, and it suits a single residential furnace or tankless water heater making a modest amount of condensate. Many inline units have a refillable cartridge so you swap or top up the media without cutting the pipe.
The box or chamber type is a larger open vessel the condensate flows into and through, holding more media and giving the water more dwell time against it. The extra volume is what a boiler or a high-input appliance needs, because more condensate at a lower pH needs more media and more contact to come out neutral. On a commercial boiler the neutralizer is a real tank, not a tube.
Pick the type by the condensate volume and how acidic the water is, not by what is cheapest on the shelf. An inline tube on a big mod-con boiler is undersized the day it goes in. A chamber on a small furnace is fine but more than the job needs. Size first, then choose the shape that holds that much media.
How do you size a condensate neutralizer?
You size a neutralizer to two things: how much condensate the appliance makes, and how long that water has to touch the media to come out neutral. The volume scales with input and efficiency, and the field estimate most manufacturers use is roughly 1 gallon of condensate per hour for every 100,000 Btu of input on a condensing appliance. A 100,000 Btu furnace makes on the order of a gallon an hour. A 1,000,000 Btu boiler makes ten times that, and it needs a neutralizer ten times the size.
Most neutralizers are rated by both Btu input and gallons per hour for exactly this reason. Match the rating to the appliance, and to the total if more than one unit shares the line. Two furnaces on one neutralizer means you size for both running at once.
Contact time is the part people skip. Enough media has to be in the path that the water dwells against it long enough to react, and more acidic condensate needs more dwell. Undersize the media or run the water through too fast and the outlet pH never comes up, even with good media in the tube. When in doubt, size up. The penalty for too much media is a slightly bigger box. The penalty for too little is acid in the drain.
| Appliance input | Rough condensate volume | Neutralizer |
|---|---|---|
| 100,000 Btu furnace | About 1 gph | Inline tube or cartridge |
| 200,000 Btu boiler | About 2 gph | Larger inline or small chamber |
| 500,000 Btu boiler | About 5 gph | Chamber sized to flow |
| 1,000,000 Btu boiler | About 10 gph | Tank-style chamber |
Installing the neutralizer in the condensate line
The neutralizer goes downstream of the appliance trap and upstream of the drain or the pump, in line with the condensate so all of it passes through the media. The order matters: trap first so the appliance drains correctly, then the neutralizer, then the discharge. Plumb it so every drop is treated, with no bypass tee that lets condensate skip the media.
Set it level and give it fall. The condensate has to flow in one end and out the other by gravity, and a neutralizer that sits tilted or in a low spot pools water and channels it past the media instead of through it. Most inline units have an inlet and an outlet marked for direction and a vent or a fill cap up top. Install it the way it is marked, not backward, because flipped end-for-end the water short-circuits the media.
Mount it where a hand can reach it. The media gets refilled, so a neutralizer glued into a buried run or stuffed behind the unit where nobody can open it is a neutralizer that never gets serviced. Leave the cap or the cartridge accessible. The condensate drain guide covers the trap and the slope on the line itself. The neutralizer just rides in that line, treated water out the bottom.
The condensate pump and acid-resistant materials
When the drain is above the appliance, a condensate pump lifts the water, and on a condensing unit that pump lives in acid. Use a pump rated for condensing appliances, with an acid-resistant housing, impeller, and check valve, because a standard cooling-condensate pump corrodes and seizes on the acid in months. The cheap pump that came off a cooling job is the wrong pump here.
Neutralize before the pump, not after. Put the neutralizer between the appliance and the pump so the water hitting the pump is already treated, which protects the pump itself on top of the drain downstream. A pump fed raw acid is being attacked from the inside even if it is nominally acid-rated, and the neutralizer ahead of it is the difference.
The pump gets its own safety float wired to shut the appliance down if the water rises past where the pump should have cleared it, the same as any condensate pump. The condensate drain guide covers that wiring and the pump logic in full. The only thing the condensing appliance changes is that everything the acid touches, the pump included, has to survive the acid.
How do you check the outlet pH?
Check the pH at the outlet of the neutralizer, where the treated water leaves, with a pH test strip or a meter, and compare it to the target the code and the manufacturer set. The common target is to bring the discharge up to at least pH 5, and ideally toward neutral, somewhere in the 6 to 7 range, before it enters the drain. Codes and sewer authorities phrase the limit differently, so confirm the number you have to hit for the jurisdiction.
Test the outlet, not the inlet. The inlet is the raw acid and you already know it is low. What you are proving is that the water coming out is high enough. Catch a sample at the discharge while the appliance is running and making condensate, because an idle unit gives you stale water sitting in the media that reads higher than the real running condition.
A strip is enough for a field check. The reading tells you two things: whether the neutralizer is doing its job today, and, tracked over time, when the media is wearing out. An outlet pH that has crept back down toward 5 is the media telling you it is nearly spent.
Buy strips that actually resolve the range you care about. A pool or aquarium strip that only reads in whole numbers from 6 up is useless for confirming you cleared pH 5 on water that started near 3. Use a strip graduated through the acidic range, or a cheap pen meter calibrated against a buffer solution, so the number you write down means something.
Refilling the media is the maintenance that matters
The media is consumed, so it gets refilled, and this is the single maintenance task that keeps the whole device honest. As the media reacts and dissolves, and as the spent chips crust over, the neutralizer treats less and less until the acid passes straight through untreated. Nothing alarms. The tube still looks full of chips. The pH at the outlet is the only thing that tells you, and only if someone checks it.
Plan on refilling once or twice a year, and use the outlet pH to set the real interval. A heavy-use boiler running all winter, or an oil unit with more acid in the water, exhausts media faster than a furnace that runs a few months. Replace the media, or top it off and stir out the crusted surface, when the discharge pH drops back toward 5 or on the manufacturer's schedule, whichever comes first.
This is the item that gets dropped. The neutralizer goes in at install, passes its startup pH check, and then nobody opens it again for five years while the media quietly exhausts and the cast iron drain corrodes. Put the refill on the maintenance agreement and check the pH at every service visit. A neutralizer nobody refills is a decoration.
Is a condensate neutralizer required by code?
Often, yes, but it depends on the code adopted and what the condensate discharges to, so confirm it for the jurisdiction. The plumbing code treats acidic condensate as a corrosive waste and calls for it to pass through an approved dilution or neutralizing device before it enters the drainage system, a requirement carried in the International Plumbing Code and its counterparts. Many appliance manufacturers require neutralization in their installation instructions independent of the local code. When the manufacturer requires it, that requirement stands on its own.
Discharge limits add a second layer. Wastewater rules commonly prohibit discharging liquid below about pH 5 into a public system, on the grounds that it corrodes the infrastructure, which is the regulatory reason the outlet target exists. The exact pH limit and whether neutralization is mandatory are set by the adopted plumbing code, the local amendments, and the sewer authority, so verify them rather than carrying one number everywhere.
Where it is most clearly required: a cast iron or metal drain, a concrete trench, and a septic system. On those, neutralization is doing structural or biological work and is the safe assumption even before you read the local rule.
Acidic condensate and septic systems
A septic system runs on bacteria, and acid kills bacteria, so untreated condensing-appliance condensate going to a septic tank is a slow poison to the thing that makes the system work. The acid knocks back the bacterial colony that breaks down waste in the tank, and a weakened colony means a tank that does not digest and a field that fails sooner. The volume seems small, but a condensing furnace and water heater running all season add up.
On a septic system, neutralize the condensate, full stop, whether or not the local code spells it out. This is the case where the downstream consequence is expensive and biological rather than a corroded pipe you can replace. Some jurisdictions and manufacturers are explicit that condensate to a septic system must be neutralized.
The same logic applies to a private well or any sensitive disposal point. If the water is going somewhere a living system or a vulnerable surface has to absorb it, the acid is a problem worth solving with a neutralizer.
Oil-fired condensing appliances run more acidic
Oil-fired condensing appliances make more acidic condensate than gas, because oil carries more sulfur and the sulfur forms sulfuric and sulfurous acid on top of the carbonic and nitric acid every condensing appliance makes. The condensate runs lower on the pH scale, and there is more acid per gallon to neutralize.
Size the neutralizer up and expect the media to exhaust faster. More acid means more media consumed per gallon and a shorter refill interval, and the higher acidity needs more contact time to bring the discharge up to target. A neutralizer sized for a gas furnace is undersized on an oil unit of the same input. Follow the appliance manufacturer's guidance, which on oil condensing equipment usually calls for a larger neutralizer and a more frequent media check.
Freeze protection on the condensate line
The condensate line, neutralizer included, has to be kept from freezing, because a condensing appliance makes water whenever it runs, including the coldest nights when it runs hardest. A line or a neutralizer run through an unheated space, an attic, a crawlspace, or out a sidewall, can freeze, block, and back the condensate up into the appliance, which on many units trips a safety and shuts the heat off in the middle of a cold snap.
Keep the line and the neutralizer in conditioned space where you can, slope it so water does not stand and freeze, and heat-trace or insulate any run that has to pass through the cold. The condensate drain guide covers freeze protection on the line in full. The neutralizer is one more thing in that line that holds water and can freeze, so it belongs on the warm side of the building.
Commissioning: prove the pH at startup
At startup, with fresh media in the neutralizer, confirm the device actually works before you leave. Run the appliance until it is making condensate, catch a sample at the neutralizer outlet, and check the pH against the target. Fresh media on a correctly sized unit should bring the discharge well up toward neutral. A low reading at startup means the media is wrong, the unit is undersized, the water is short-circuiting the media, or it is plumbed backward.
This is also where you set the baseline. Record the startup outlet pH and the appliance input so the next tech knows what good looked like on day one and can see how far the media has drifted since. A neutralizer that reads fine at commissioning and is never checked again is running on faith. Prove it once at startup, write down the number, and put the recheck on the service schedule.
Why is the neutralizer not raising the pH?
When the outlet pH comes back low, the cause is almost always one of a short list. The media is exhausted or crusted over, which is the most common by far on an older install, and the fix is fresh media. The unit is undersized for the condensate volume or too acidic a source, so the water does not get enough contact, common when an inline tube was put on a boiler that needed a chamber. The neutralizer is plumbed backward or sits tilted, so the water channels past the media instead of through it.
A few more round it out. The flow is too fast because the media bed is too shallow. A bypass or a cracked housing lets condensate skip the media. And the simplest one: the unit clogged with sediment and crusted media, backed up, and the condensate found another path or overflowed. Check the pH first, then open the unit. The reading tells you whether you are chasing a worn-out consumable or an install problem.
Condensing boilers in facilities and data centers
Large facilities and data centers that run condensing boilers for heating or a hydronic loop make condensate at a scale that turns the neutralizer into a real piece of equipment, a tank of media sized to the combined input, not a tube. The volume is continuous through the heating season and the input is high, so the media exhausts on a schedule that has to be managed, not forgotten.
The stakes are the building's drainage and any on-site treatment, plus uptime. An untreated high-volume acidic discharge corrodes cast iron drains and floor sinks in mechanical rooms quickly, and a failed neutralizer on a million-Btu boiler puts a lot of acid into the system. Size the chamber to the full load, monitor the discharge pH on the facility's maintenance program, and treat the media refill as scheduled plant maintenance like any other consumable.
What to document
The neutralizer record is the proof it was sized, installed, and tested right, and it is the baseline the next service measures against. If the drain starts to corrode or the discharge fails a pH check, the install record is what shows the chamber was sized and the media charged correctly to begin with. Capture the appliance it serves, the media and the size, and the pH you measured.
Record the appliance and its input, the neutralizer type and media, the startup outlet pH and the date, and the target you held to. Note when the media was last refilled so the interval is visible. The table below is the core set. A tool like tradeos keeps the readings, the dates, and the photos with the appliance so the next tech is not guessing at the media age.
| Field to record | Why it matters |
|---|---|
| Appliance and input (Btu, AFUE) | Sets the condensate volume and the neutralizer size |
| Neutralizer type and media | Inline or chamber, calcite or magnesium oxide blend |
| Startup outlet pH and date | Proves it worked and sets the baseline |
| Target pH and source | Ties the limit to the code or the manufacturer |
| Last media refill date | Shows how old the consumable is |
| Discharge point | Cast iron, concrete, pump, or septic raises the stakes |
| Acid-resistant pump, if used | Confirms the pump survives the condensate |
Common mistakes
- No neutralizer at all on a condensing appliance draining to cast iron, concrete, metal, or a septic system.
- Letting the media exhaust without refilling, so the outlet pH drops and untreated acid passes through.
- Undersizing the neutralizer or giving the water no contact time, so it passes through under-treated.
- Installing it backward or without slope, so the condensate channels past the media.
- Never checking the outlet pH, so a spent neutralizer goes unnoticed until the drain corrodes.
- A clogged neutralizer that backs up and overflows, or pushes condensate back into the appliance.
- Feeding a standard, non-acid-rated condensate pump from an untreated condensing line.
Field checklist
Want this checklist to run itself on every job — with photo proof and a signed record crews can hand the customer? That's FieldOS.
Standards and references
The plumbing code is where the disposal requirement lives. The International Plumbing Code and its counterparts treat acidic condensate as a corrosive liquid and call for it to pass through an approved dilution or neutralizing device before it enters the drainage system. The section number and the exact wording shift between editions and between the IPC and the UPC, so confirm the requirement against the code the jurisdiction actually adopted and any local amendments before you cite it.
Discharge limits come from the wastewater side. Local sewer authorities and federal pretreatment rules commonly prohibit discharging liquid below about pH 5 into a public system, which is the basis for the outlet target. The appliance manufacturer's installation instructions carry the unit-specific requirement: whether neutralization is required, the media to use, and the size for the input. Where the instructions require it, the listing and the instructions govern regardless of the local minimum.
Cite the body that owns the point. The plumbing code and the sewer authority own the disposal and the pH limit. The manufacturer owns the appliance-specific requirement and the sizing. The AHJ and the adopted edition control the rest. Hedge the pH number and whether neutralization is mandatory to the code and the manufacturer, because both vary, and treat the acid damage to metal, concrete, and septic as the constant that justifies the neutralizer even where the local rule is silent.
Units, terms, and conversions
Condensate neutralization crosses a couple of unit systems and a few names, so the same idea reads differently across a code section, a submittal, and a spec sheet.
pH runs on the 0 to 14 scale, with 7 neutral, below 7 acidic, and each whole number a tenfold change in acidity, so pH 3 is a hundred times more acidic than pH 5. Condensate volume is in gallons per hour in the field and liters per hour in metric work, and it tracks input, roughly 1 gph per 100,000 Btu on a condensing appliance. Input is in Btu per hour or in kW. Efficiency is AFUE for furnaces and boilers, where 90 percent and up means condensing. The media is sold by weight and by calcium carbonate percentage.
- Condensate neutralizer
- A tube or chamber of alkaline media that raises the pH of acidic condensate before disposal
- Acidic condensate
- The weak acid a condensing appliance makes when flue-gas water vapor condenses, commonly pH 3 to 4 on gas
- Neutralizing media
- Calcium carbonate (limestone, marble, calcite) or magnesium oxide that reacts with the acid and raises pH
- Contact time / dwell
- How long the condensate sits against the media; too little and the water under-treats
- AFUE
- Annual Fuel Utilization Efficiency; 90 percent and above indicates a condensing appliance
- pH
- The acidity scale from 0 to 14, neutral at 7, where each step is a tenfold change
- Condensing appliance
- A furnace, boiler, or water heater that condenses flue-gas vapor to recover latent heat, making acidic condensate
FAQ
What is a condensate neutralizer?
A condensate neutralizer is a tube or chamber of alkaline media, usually calcium carbonate or magnesium oxide, plumbed into the condensate line of a condensing furnace, boiler, or water heater. The acidic condensate flows through the media, which reacts with it and raises the pH toward neutral before the water reaches the drain.
Why is condensate from a high-efficiency furnace acidic?
Because the furnace condenses the flue gas to recover heat, and combustion products dissolve into that water as acid. Carbon dioxide, nitrogen oxides, and sulfur form carbonic, nitric, and sulfuric acid, leaving the condensate around pH 3 to 4 on natural gas. Oil-fired units run lower because the fuel carries more sulfur.
Do you need a condensate neutralizer?
You need one whenever a condensing appliance discharges to something the acid harms: a cast iron, galvanized, or metal drain, a concrete floor or trench, a condensate pump, or a septic system. Many plumbing codes and appliance manufacturers require neutralization. A PVC line straight to a sewer is the one case where the pipe shrugs it off.
How often do you replace neutralizer media?
Plan on once or twice a year, and let the outlet pH set the real interval. Heavy-use boilers and oil units exhaust media faster. Replace it when the discharge pH drops back toward 5 or on the manufacturer's schedule. The chips crust over and stop reacting before they visibly run out, so check the pH, not the level.
Limestone or magnesium oxide: which media is better?
Both work. Limestone and marble are calcium carbonate, cheap and common, but lower grades crust over as insoluble minerals coat the chips. Magnesium oxide, often blended with calcite, reacts faster and holds the pH higher, which helps on more acidic oil or high-volume condensate. Use media rated 90 percent or more calcium carbonate, or the blend the manufacturer specifies.
What pH should the neutralizer discharge be?
Bring the discharge up to at least pH 5, and ideally toward neutral, around 6 to 7, before it enters the drain. Wastewater rules commonly prohibit discharging below pH 5. Check the outlet, not the inlet, with a strip or meter while the appliance is running, and confirm the exact limit with the local sewer authority.
Why is my neutralizer not raising the pH?
Usually the media is exhausted or crusted over, so refill it first. Other causes: the unit is undersized for the condensate, it is plumbed backward or tilted so water channels past the media, or the bed is too shallow for contact. Check the outlet pH, then open the unit to find which one.
Do you need a special condensate pump for a condensing furnace?
Yes, if the drain is above the unit. Use a pump rated for condensing appliances with an acid-resistant housing, impeller, and check valve, because a standard cooling-condensate pump corrodes on the acid. Put the neutralizer ahead of the pump so the water is treated before it reaches it, protecting the pump and the drain.
Can condensing-furnace condensate go to a septic system?
Only neutralized. The acid kills the bacteria a septic tank relies on to break down waste, so untreated condensate weakens the colony and shortens the field's life. Run it through a neutralizer first, whether or not the local code spells it out, because the downstream damage on a septic system is biological and expensive.
People also ask
Codes cited in this guide
This guide is written and reviewed against the published standards below. Always confirm the current adopted edition with the authority having jurisdiction.