Calling the Captain

GW

#captainco These pictures were taken six minutes apart. I’m a little foggy on how rising oxygen equates to rising co. Any ideas? Basic water heater natural gas 
The pictures are not in correct order. CO was going from low and climbing

captainco

Rising O2 would be possible as draft increases but normally at those levels CO should not be going up. That only occurs when you are underfired and usually above12% O2 or higher.

Did you measure the water heater on both sides of the baffle? This might give us an additional clue. The only things I can think of that could cause this type of problem is flame impingement(flames lifting as draft increases) or burner alignment causing some type of impingement.. As draft increases the problem increases.

Robert O'Brien

Probe isn't moving?

WMno57

Could condensing from a cold start cause this?

Zman

Never Mind...

GW

Jim I didn’t purposely try both sides. next time

Good idea on the rising draft and impingement 

I know you said rising CO is never a good thing. But draft seemed good and plenty of air 
it seemed 

Seemed like the CO was not getting super weird (dangerous)

I stuffed a rag around half the diverter for 20 seconds and no noticeable difference 

GW

WM the metals should heat up within a minute or so I would think. 

GW

Robert maybe a little but the numbers were increasing at the same general pace 

WMno57

40 gallons of 50 degree water will act as a big heat sink. Similar to soldering holes on a gas tank filled with water (never get hot enough to melt the solder) or boiling a pot of water on a gas stove (initially, condensation will form on the outside of the pot).
A water heater is normally full of 120 degree water. I've never done a combustion analysis. So I'm asking the combustion experts.
Is it possible a combustion analysis during a water heater cold start may not give the same result as an analysis during normal operation?
I cold started my boiler a week ago after letting it sit all summer. Added gallons of 50 degree water first, due to draining my air over water bladder-less tank. Had condensation for about 20 minutes. 70 year old boiler, and former gravity hot water pipes, so large volume of water to heat up.

captainco

Most water heaters operate with low inlet water temperatures. The flame temperature is 2800 degrees at 6% O2 and shouldn't condense. Usually underfiring is a main reason for condensation or improper venting if venting takes too long to be established,
If this was a venting or combustion air problem the O2 would be dropping not rising. Draft does increase as equipment gets hotter but normally a drafthood eliminates its effect, but not always. The fact that covering the drafthood didn' t help still leads me to believe this is some type of impingement. Could be caused by dirt in or on the burner. A flue temperature would have also be helpful. A burner slightly off center or not level could also be the problem, which is why we measure both sides of the baffle.

mattmia2

What about the inlet screens on newer water heaters being clogged?

captainco

That would cause the O2 to be low.

EBEBRATT-Ed

I have seen boilers that were set up properly and the Co when the boiler is cold is usually higher than when the boiler warms up. Never seen the reverse. Weird

GW

mattmia2 said:

What about the inlet screens on newer water heaters being clogged?

don’t think so- that would be a “fixed” variable- or a mechanical issue. 

 Rising CO is normally “intestine” related. Gasses are struggling to get in (fresh air) or out (chimney issues) 

GW

Jim is this the jam these days?
Bacharach Fyrite INSIGHT Plus Combustion Analyzer with Reporting Kit with extended life sensors

offdutytech

@GW I have the Fyrite Insight and wished I would have bought the Insight Plus. One of the things I liked about both was the ability to use Measure Quick App. to be able to view stuff in a user friendly format. I started using the Measure Quick for AC service calls and have started to use it more on the combustion side. I had my eye on a Wohler combustion analyzer as well, but having to buy my own tools had to find a more budget friendly one. 

captainco

The Insight Plus has a lot of bells and whistles. The reporting App should be upgradeable for all units. It was free, Just get the info from Bacharach and download from your computer.
The Insight Plus - Tune Rite has similar diagnostics as NCI. That might be because we helped them program it. Because unstable readings and draft can be included, not all problems can be solved but you can eliminate things that aren't.
CO sensors last for 5 to 10 years, O2 sensors 2 to 2-1/2 years. Based on cost I am not sure the 3 year sensor is a good value. You can ruin it just as fast as the 2 year sensor.

GW

Very good, can the technician replace the sensors on his own? I kind of miss the old days

SuperTech

GW said:

Very good, can the technician replace the sensors on his own? I kind of miss the old days

Gary the new Testo 300LL has field replaceable sensors and a five year warranty. I've had mine for about a year now I love it. Thanks for starting this post. I love combustion analysis discussions and opportunities to learn from @captainco.

captainco

If anyone is looking to buy a combustion analyzer this winter better hurry. Bacharach is out until Spring and Testo is just about out. Because most use computer chips from China there is a long wait.

GW

I hear that Jim I was browsing the other day with credit card in hand- nothing.
I’ll keep looking 
Testo as good as the Bacharach? My 310 is on the fritz. Was on a job today and the CO2 was not believable. (Brand new oil job so I know the general numbers to expect) 
Super kinda likes his 

captainco

The Testo 310 is okay except you have to send it in to replace the O2 sensor. Also the probe does not remove which can allow more water to build up inside. I think Bacharach and Testo are similar but my history with Bacharach is more favorable.
I don't have aproblrm with UeI exvept the service side. All analyzers work okay, it is the long term durability that is my concern.

GW

I can not keep track on the verbiage, which is the good one?

Bacharach 0024-8517
Combustion Analyzer Insight Long Life with 02 Sensor

Bacharach 0024-8518
Combustion Analyzer Reporting Kit with O2 Sensor LCD Display

captainco

The 8517 doesn't include a printer and the 8518 does. Both can have the long life O2 sensor but I still prefer the 2 year because it is easier to get and you are paying for the extra year.
Both should have the recording app but their specs don't state that. I will be back on Monday with an answer.
By the way they aren't available till spring!!

GW

Thanks Jim, my local vendor is showing they have a couple of these in their inventory. I’ll scoop one or two of them up if you think it’s a good machine. Thank you

GW

Also, is the printer pretty interchangeable? I’m happy to pay for a new printer, just curious if the printer I use for my Testo will work for the Bachrach. Either way is completely fine

captainco

It is a good unit. The printers are not interchangeable.

GW

Well then, seems like it’s time to contribute towards this freaked out economy

SlamDunk

will the Testo indicate a bad o2 or co sensor?I have a 330 that is about three years out from a repair.  

captainco

Most analyzer don;t say the O2 sensor is bad, most just stop reading on the screen or show all stars or lines. But some look like they are good don't respond. Using your breath and exhaling into the probe for 15 seconds, the O2 should drop below 17%. Either the sensor is bad or you have hose or probe leaks. Also If a O2 sensor gets wet it will stop working until it is dried out. Many time in the past when contractors brought their analyzers in for repair I found their O2 sensor wet. I took it out and left it set over night and it was fine the next day. No your analyzers and don't waste money on repairs that aren't needed.

SlamDunk

Thanks!

tim smith

I got to know my 10 + or so testos, uei etc way more than I wanted. Broken probe connectors, o rings leak. Replace 02 and Co sensors. Yada yada yada. The ones I detested least was long life replaceable cell UEI. I had test 325, 327-1, 330s. To name a few.