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Last Updated on October 2, 2026 by Muhammad Toqeer
First, check whether you need one at all. The acid comes from the gas-fired side — a condensing furnace, boiler or water heater. Condensate off an air-conditioning coil is not acidic, and a mid-efficiency furnace does not make it either.
If you do need one, size it in BTU per hour off the appliance nameplate, not in gallons. That is a different number from everything else on this site, and it is the number every manufacturer publishes its range in.
And the target is a window with a ceiling. One maker publishes neutralized condensate as above 4.0 and below 9.0; another gives 5.0 to 9.5. Neither too acidic nor too alkaline, in their own words — which means this is not a device you add more of until the problem goes away.
The three numbers before any model
Do you have acidic condensate
It comes from high-efficiency gas-fired appliances — condensing boilers, condensing furnaces and condensing water heaters. Those are the appliances that pull enough heat out of the flue gas to condense it, and the resulting water carries the acid.
Condensate from an evaporator coil is the other category entirely. If the only thing feeding your pump is the air handler in summer, there is nothing here to neutralize.
One-minute check: does the furnace have a plastic flue through a sidewall rather than a metal one up a chimney, and does it drain water in winter? That is the condensing appliance. If the only water you see is in July, it is the AC.
How acidic, and how neutral it has to end up
As published, the raw condensate is pH 2.5 to 4.0, with a second manufacturer giving 2.9 to 4.0.
And the neutralized target, from the same two sources: “neither too acidic nor too alkaline — its pH levels need to be above 4.0 and below 9.0“, and “between 5.0 and 9.5“.
The ceiling is the part nobody repeats. Over-alkalized discharge is as much a failure as acidic discharge, and one maker explicitly describes its products as raising pH “without over alkalizing them.”
What size
Published in BTU per hour of the appliance, with the efficiency stated alongside, because efficiency decides how much flue gas is actually condensed:
| Appliance rating | Condensate produced |
|---|---|
| 400,000 BTU/hr at 93 % efficiency | 1.6 gal/hr |
| 1,000,000 BTU/hr at 93 % efficiency | 4 gal/hr |
Residential furnaces sit well under the bottom of that, which is why the smallest bodies in most ranges start around 220,000 BTU/hr and cover an ordinary house comfortably.
The code position, stated as a duty rather than a section
The requirement is not a condensate-specific clause. It is a general rule about corrosive waste: liquids that would destroy or injure a drain, sewer, soil or waste pipe must not be discharged into the plumbing system without being thoroughly diluted, neutralized or treated by passing through an approved dilution or neutralizing device.
That duty is what to quote to a plumber. The section number is what your inspector supplies, because the numbering differs between the model codes and between state amendments, and secondary sources disagree about it. Nothing here tells you which section applies in your jurisdiction — the device requirement does not change, but the citation does.
And the thing being protected is specific. Cast iron is roughly ten times more vulnerable to this corrosion than the alternatives, so an old house with cast-iron drains has more at stake than a new one with PVC.
The eight worth knowing
Axiom NC-1 NeutraPal — the small one, with the flow rate published
Axiom NC-1 NeutraPal — maximum condensate flow 1.6 gal/hr, rated for 400,000 BTU/hr at 93 % efficiency. Charged with Axiom’s LipHter⁺ magnesium oxide media. Ships with 10 ft of vinyl tubing and unions to remove it from the system for a media change. “All corrosion resistant materials”, “low profile design for appliances with a near floor condensate drain.” Replacement media is NM-1.
Who it is for: any ordinary residential condensing furnace or boiler, and particularly one whose drain sits low to the floor with no height to work in.
The honest drawback: the published pH outcome is described only as “a more neutral level.” There is no target figure on the product page, so the verification is still a test strip rather than a specification.
Axiom NC-2 NeutraPal — the same thing, two and a half times the flow
Axiom NC-2 NeutraPal — maximum flow 4 gal/hr, rated for 1,000,000 BTU/hr at 93 % efficiency. Same LipHter⁺ media, same unions, same 10 ft of tubing. Takes 2 × NM-1 for an exact refill.
Who it is for: a large boiler, a combi system, or two condensing appliances sharing one drain.
The honest drawback: it needs twice the media at every change. A unit bought with headroom you do not need costs more every year, not just once.
Neutra-Safe CN2-220C — the 220,000 BTU clear tube
Neutra-Safe CN2-220C — 220,000 BTU/hr, a 2-inch tube with 12 tubes, connections “(2) ½” Male x ¾” PVC socket fittings”, bi-directional, and “horizontal installation only.” Recharge kit 22RCK-S.
Who it is for: the standard residential case, plumbed into a horizontal run.
The honest drawback: horizontal only. If the drain leaves the appliance and drops, this body cannot follow it — and nothing about the model number says so until you read the table.
Neutra-Safe CN2-220V — the one that may stand up
Neutra-Safe CN2-220V — 220,000 BTU/hr, 2-inch, 12 tubes, “vertical or horizontal installation”, with PVC socket fittings, threaded 90s and a stainless steel screen. Recharge kit 22RCK-S, same as the horizontal models.
Who it is for: a tight mechanical room where the only space is on the vertical.
The honest drawback: it is the odd one out in its own family, so it is the one most likely to be substituted by a counter that sees three models at the same capacity. Order it by the full model number, including the V.
Neutra-Safe CN2-220BC — the same body with barbs
Neutra-Safe CN2-220BC — 220,000 BTU/hr, 2-inch, 12 tubes, horizontal only, with the ½” male × ¾” PVC socket fittings plus “(2) Barb fittings.” Recharge kit 22RCK-S.
Who it is for: a run that arrives in flexible tubing rather than rigid PVC, which is most of the pump-fed ones.
The honest drawback: nothing it does, the `C` cannot do with adapters. You are buying fittings, not capacity, and it is worth knowing that is the entire difference.
Neutra-Safe CN2-300C — one size up, same body style
Neutra-Safe CN2-300C — 300,000 BTU/hr, 2-inch tube, 12 tubes, ½” male × ¾” PVC socket fittings, horizontal only. Recharge kit 30RCK-S.
Who it is for: a larger residential boiler, or a furnace and a water heater on one drain.
The honest drawback: the recharge kit changes with the body. Moving up a size changes the consumable part number too, which matters when you reorder a year later from memory.
Neutra-Safe CN4B-600C — where the bodies get bigger
Neutra-Safe CN4B-600C — 600,000 BTU/hr, a 4-inch tube with 6 tubes, connections “(2) ¾” Male x ¾” PVC socket fittings”, bi-directional, horizontal only. Recharge kit 60RCK-S. The range continues to 850,000, 1,200,000 and 2,000,000 BTU/hr.
Who it is for: light commercial, or a residential system well beyond the usual.
The honest drawback: the connections step up to ¾ inch male. It is not a drop-in replacement for a 2-inch body, so moving up a size is a pipework change as well as a purchase.
A.O. Smith CN2-300 — the one that names both media
A.O. Smith CN2-300 — “Calcite and magnesium oxide media”, “clear tube for visual inspection”, “integrated unions with o-rings”, and it includes PVC adapters and mounting brackets. Described by its maker as being for “high-efficiency boilers and water heaters.”
Who it is for: anyone who would rather see the media than take a reading, and anyone fitting it themselves who does not want to source brackets and adapters separately.
The honest drawback: no BTU rating is published on the product page — the detail lives in a separate spec sheet. A device you cannot size from the page you are buying it on is a device you have to go and check.
Side by side
| Model | Capacity | Body | Installation | Recharge |
|---|---|---|---|---|
| Axiom NC-1 | 400,000 BTU/hr @ 93 % — 1.6 gal/hr | low profile, magnesium oxide | unions, 10 ft tubing | NM-1 |
| Axiom NC-2 | 1,000,000 BTU/hr @ 93 % — 4 gal/hr | low profile, magnesium oxide | unions, 10 ft tubing | 2 × NM-1 |
| Neutra-Safe CN2-220C | 220,000 BTU/hr | 2″, 12 tubes | horizontal only | 22RCK-S |
| Neutra-Safe CN2-220BC | 220,000 BTU/hr | 2″, 12 tubes, + barbs | horizontal only | 22RCK-S |
| Neutra-Safe CN2-220V | 220,000 BTU/hr | 2″, 12 tubes | vertical or horizontal | 22RCK-S |
| Neutra-Safe CN2-300C | 300,000 BTU/hr | 2″, 12 tubes | horizontal only | 30RCK-S |
| Neutra-Safe CN4B-600C | 600,000 BTU/hr | 4″, 6 tubes, ¾” connections | horizontal only | 60RCK-S |
| A.O. Smith CN2-300 | not published on the product page | clear tube, calcite + magnesium oxide | integrated unions | not published |
All eight are current catalogue items on the manufacturers’ own sites, checked 2 October 2026.
The media, and why the clear tube matters more than the choice
Two materials are in use and the market is not split cleanly between them.
Magnesium oxide, as pellets — one maker describes its media as “manufactured using high-quality magnesium oxide”, with a “dense pellet shape” that “maximizes surface area”, “virtually dust-free” and “safe to handle.”
Calcite, as stones — another publishes its media as “98 % pure calcite stones, with a touch of magnesium oxide.”
And one product lists both by name. So the honest position is that both are in production from reputable makers and neither is a disqualifier.
What does change the ownership experience is whether you can see the media. A clear tube turns an annual question into a glance. Everything else is a test strip in a drain line, which is a job people stop doing.
Pro note: the media is consumed, not fouled. It dissolves to do its work, which is why the level drops and why the recharge kit is a named part rather than a cleaning procedure.
Where it goes in the run, and what that affects
Upstream of the pump, not after it. The point is to protect everything the water passes through on its way out — which includes the pump itself, its tank, and the drain beyond it.
Which is why this shows up as a pump problem first. A pump that has been moving aggressive condensate shows it in the materials, and the copper test described there is the simplest way to find out whether yours is aggressive before you buy anything.
It is also worth knowing what a neutralizer will not fix. It will not stop a pump smelling — that is biological growth, not acidity. It will not make a pump that runs without moving water start moving it, and it will not stop a tank overflowing. Those are three different faults and none of them is pH.
How to choose, in order
First, is the condensate acidic at all? Condensing gas appliance, yes. AC coil only, no.
Second, what does the appliance’s nameplate say in BTU/hr? That is the sizing input, and the smallest bodies cover most houses.
Third, which way does the drain run? Horizontal-only is the default across most ranges, and the vertical-capable model is usually a separate part number.
Fourth, what arrives at the inlet — rigid PVC or flexible tubing? That decides whether you want the barbed variant or a pair of adapters.
Fifth, do you want to see the media? A clear tube is the difference between checking it and meaning to.
And last, note the recharge kit’s part number now, while you have the model in front of you, because it is body-specific and you will want it in a year.
When this needs a pro
The fitting itself. It goes into a drain line from a gas appliance, and in most jurisdictions the appliance’s condensate disposal is inspected.
Deciding whether your installation already complies. Some condensing appliances ship with a neutralizer and some do not; some local amendments require one and some treat the general corrosive-waste rule as sufficient. That is a question for whoever signs off the work.
Any appliance that is dripping from somewhere it should not. Acidic condensate finding its way out of the intended path is a heat-exchanger question before it is a drain question.
What you can do yourself: read the BTU rating off the furnace nameplate, look at whether the drain runs flat or drops, and check the inlet is PVC or tubing. Three observations, no tools — and they narrow the list to one or two part numbers before you call anyone.
FAQ
Do I need a condensate neutralizer?
Only if you have a high-efficiency gas-fired appliance — a condensing furnace, boiler or water heater. Those produce condensate published at pH 2.5 to 4.0. Condensate from an air-conditioning evaporator coil is a different category and is not what a neutralizer is for.
What pH should condensate be after neutralizing?
Inside a window, not above a floor. One manufacturer publishes it as above 4.0 and below 9.0, another as between 5.0 and 9.5 — and both describe the goal as neither too acidic nor too alkaline. Over-alkalized discharge is a failure in the same way acidic discharge is.
How do I size a condensate neutralizer?
In BTU per hour off the appliance nameplate, not in gallons. Manufacturers publish the rating with the efficiency attached — for example 400,000 BTU/hr at 93 % efficiency corresponding to 1.6 gal/hr of condensate. Residential furnaces usually sit well inside the smallest body in a range.
Can a condensate neutralizer be mounted vertically?
Only if the model says so. In one maker’s range, three models share the same 220,000 BTU/hr capacity, the same 2-inch tube and the same twelve tubes, and only the one ending in V is listed for vertical or horizontal installation. The others are horizontal only.
Which is better, calcite or magnesium oxide media?
Both are in current production from established manufacturers, and at least one product uses calcite and magnesium oxide together. The more useful differentiator for an owner is whether the body has a clear tube, because that is the only way to see how much media is left without opening it.
How often does the media need replacing?
It is consumed rather than fouled, so it depletes with use rather than on a fixed schedule — which is why a clear tube is worth having. Each body has its own named recharge kit, so note that part number when you buy the unit rather than looking it up a year later.
