Improper Combustion - could it be too high gas pressure?

Jim100Flower

A home energy audior from MassSave told me my boiler has high CO due to improper combustion. He drilled two holes in the flue (photo), inserted a probe in the lower hole, had me turn up thermostat and turn on the range hood fan, and took a reading after a minute.

Assuming he is correct, what could cause improper combustion?

I am 110' above sea level. It is not an altitude problem.

The utility room is part of a storage area of 255 square feet and has 2 doors opening to a large basement and 3500 sq ft house. It is not a lack of air problem.

When the boiler is running, smoke from a blown out match is pulled up the draft hood and also pulled in at the bottom of where the flue enters the wall. It is not a draft problem.

I'm told there is nothing to clean or adjust on a gas boiler.

Could my gas pressure be too high?

Here is my evidence for high gas pressure:

1. When the boiler is off and I read the gas meter over an hour the pilots (furnace and conventional HW tank) consume 2 cu ft per hour.

2. The pilot looks and sounds large (photo).

3. The gas usage during a mild November with conservative heat (60 F and below) was 143 CCF.

The house was abandoned for 5 years before I moved in and the gas was off for most of that time. Maybe a regulator rusted or something. Is the regulator in the meter? How can I find out if my gas pressure is too high?

Boiler: Burnham P-208-W Installed 1988 Manufactured 1983



DOE HTG cap - 190,000

Water BTU/hr - 165,200



AGA rating

Input BTU/hr- 232,000

Gas pressure - 14 max and 4.5 min

Manifold pressure - 3.5



ASME max working pressure

Water - 30 psi

Min relief cap - 232

JStar

Boiler

What was the CO level?

Was there any other combustion numbers? O2? CO2? Flue temperature?

What was the draft before and after the draft hood?

Jim100Flower

PPM

CO in flue 1600 ppm. "normal" is 100 ppm.

The guy did not give me any other numbers.



There is no CO in the adjacent hallway where there is a numerical CO alarm.

icesailor

"assuming he is correct"

You said in part:

"assuming he is correct".

He probably isn't.

Unless that is one large hacienda, the boiler is WAY too big. It looks like a really spiffy install from the past.

From what you describe, the inspector took a short course in MassSave home inspections. You get what you pay for. For not much, you don't get much.

Hire a real pro that knows what they are doing with a combustion analyzer.

Although that boiler may work OK, it is a prime candidate for a replacement with a Mod Con boiler. One of us here would be delighted to replace something like that and connect it up.

Did he tell you how high the CO was or did he just pull it out of his back pocket?

icesailor

High CO

I posted just before you posted the 1600 PPM. That is high. There is a reason. It needs service.

Jim100Flower

flue temperature

290 F near lower probe hole tape

150 F near upper probe hole tape

after 1+ min of firing



I used one of those laser sighted temperature guns from about 3 inches away- don't know how accurate it is.

Jim100Flower

could be wrong

I have low confidence in the MassSave guy.



He wanted to leave the holes open and I insisted he tape them up. He gave me other incorrect info, did not have the right drill bit to pierce the flue, and generally just wanted to get done and get out.

Jim100Flower

What could a service do?

What could a service do?



Plumbers tell me there is nothing to clean or adjust on a gas boiler.

unclejohn

One minute

Is not very long but the flue temp on that boiler should be well above 500*F. And there is plenty to clean on a gas boiler. All the burners and the heat exchanger for starters. If you hit the side of the flue pipe will soot fall out? You need a pro to measure your gas pressure. And while hes there ask him to pull the top off and inspect the boiler and clean if needed.

JStar

CO

You really need a professional to help. If somebody can't tell you why CO is produced, then don't let them in your house.



You need draft, O2, and CO2 numbers to decide what the problem is, without even opening up the boiler.

Jim100Flower

What could a service do?

Plumbers tell me there is nothing to clean or adjust on a gas boiler.

Jean-David Beyer

Plumbers tell me there is nothing to clean or adjust on a gas boiler.

That is what my former contractor's trained monkey told me when he came out for the first service. That is why they are my former contractor.



That is why you get a professional heating contractor and not just a plumber. I suppose it is possible that a plumber might be able to service a modern heating system, but I would not count on it.

icesailor

Proctology:

Not all plumbers are heaters. Not all heaters are plumbers. Not all plumbers (outside ot Massachusetts) are gas fitters.

You wouldn't go to a Gynacologist for a prostate problem and you wouldn't have your wife or female relative go to a Proctologist for her OB/GYN problems.

If you hire a specialist, you should get specialized help. If you hire a General Practioner, you might not get what you think you are paying for,

JStar

Plumber

That usually translates as, "I don't know how to fix it", or, "I'm too lazy to fix it".



There are definite things that you could test and do to remedy this problem. It is a major safety concern and needs to be fixed.

Jim100Flower

soot

Yes, a few black flakes drop when I hit the side of the flue.

RJ_4

mod. no

Looked up mod. on burnham site  your no. does not come up.   I would have a boiler tech pull out the burner tray and look up inside for either a plugged heat exchanger or soot between boiler sections, not sure if old burnham boilers were cast iron sectional or a different style.

Jim100Flower

Mod

A plumber told me it was 8 sections.



What is the consequence when you say you could not find mod on the Burnham site? Does that mean no one makes parts to modify this boiler?

RJ_4

mod.

Get complete mod. and serial no.   or take a picture of the nameplates  If it is a sectional boiler you should have the flue passages between sections checked to eliminate that as a problem

Jim100Flower

mod

nameplate photo

Tim McElwain

This boiler should

not be left running shut it off immediately as it is dangerous. The high level of CO says something is definitely wrong it could be any number of things such as:



1. Plugged Sections

2. Over-gassed ( check gas pressure inlet and outlet of the gas valve) clock the burner on the gas meter.

3. Determine settings which follow this level O2 at 4% or higher CO2 at 8.5% to 9.5%, CO Air free under 100 PPM, draft at -0.01, -0.02, to -0.03. Net stack temperature above 275°F Preferably between 350 to 450 for that natural gas boiler.

4. Impingement caused by mis-aligned burners or the over-gassed condition previously addressed.



Keep looking for a professional who can handle your problem.



What is your location in the country?

Jim100Flower

Boiler

Thanks. I'm north of Boston.

Tim McElwain

Contact me

by e-mail and I will connect you with someone who can help you. My e-mail is gastc@cox.net