Low NOx Steam Boiler??

PinkTavo

I live in Colorado and have a residential steam system originally installed in 1923. This home is on its second boiler, installed in 1982. I am considering what to do when it reaches the end, which I hope is still a while off.

However, Colorado passed a low NOx law for gas heating units and I am wondering if there are any boilers out there that meet this requirement. I was looking at the US Boiler SteamMax, but this doesn't have a low NOx burner. Is it possible to retrofit a low NOx burner?

I would really like to keep my steam system. It is quiet and reliable. I don't want to spend $50K to put in a short lived (10-15 yrs), high maintenance, condensing HW boiler system.

GGross

According to several sources online boilers are specifically exempt from the requirement, its just residential furnaces (scorch air) and water heaters. and there is some conflicting info when I look but it appears maybe it was paused and several additional exemptions went into play including mobile home water heater exemptions and LP unit exemptions. so you should be fine purchasing a unit that was legal last year,

PinkTavo

GGross…were your sources in reference to Colorado (Denver specifically)? I know I could ask someone in the government, but don't really want to open myself to their scrutiny. I think I will try to get the full text of the law and make sure boilers aren't included. I do have a feeling that whoever wrote it thinks that boilers are furnaces.

PinkTavo

Well, that was easier than I thought. As, GGross mentioned, it is water heaters and forced air furnaces. Here is the standard:

Section 25-7-1504
Emission standards for new products

(1)

On and after January 1, 2026, except as described in section 25-7-1506, a person shall not manufacture, distribute, sell, offer for sale, lease, or offer for lease in Colorado any of the following new products unless the emissions of the product do not exceed the following emissions limits, as applicable:

(a)

Ten nanograms of NOx per joule for water heaters with a rated heat input capacity of up to seventy-five thousand BTUs per hour and for any unit with power assist;

(b)

Fourteen nanograms of NOx per joule for water heaters with a rated heat input capacity of more than seventy-five thousand and less than two million BTUs per hour; or

(c)

Fourteen nanograms of NOx per joule for fan-type central furnaces.

(2)

Equipment that is certified to the most recent version of the Energy Star program for the relevant equipment type is deemed to comply with the requirements of subsection (1) of this section.

EBEBRATT-Ed

Never herd of a Lo NOX residential steam boiler I don't think such a thing exists. If the equipment is not made they can't hod you to some crappy spec.

TheClevelandSteamer

https://forum.heatinghelp.com/discussion/204851/low-nox-steam-boiler

Be very mindful of your elevation. There are certain parts on boilers that are unique to high altitude applications. It varies by brand, but it can be the gas valve, orifices, burner assembly.

Ironman

It looks like the regulation is aimed at manufacturers, distributors and contractors, not homeowners.

ChrisJ

Curious, if I'm remembering correctly on older cars you lowered the nox by using egr to cool elevated combustion temperatures from lean mixtures.

If that's correct how do they do it on furnaces?

EBEBRATT-Ed

@ChrisJ

I believe they recycle some of the flue gas into the burner MU air. I have never seen this in residential equipment.