I got this email from a QA program manager. Looking for feedback. Thanks

 

 

I have a question for you I'm hoping you can shed some light on.

How are we supposed to proceed with getting combustion and worst case depressurization numbers from an area that is inaccessible?

I just ran into this situation over at customer's home with a tankless water heater on his second floor.
The only option to get a flue gas sample is to set up an extension ladder in an alley which doesn't have clearances that are proper for an extension ladder.

Look forward to hearing how you would proceed on this.

Views: 36

Replies to This Discussion

 

You should be able to access the room where the water heater itself is located.  Otherwise if it is in some kind of sealed off space, then it probably doesn't meet code requirements.  So you should be able to do a worst case depressurization test on the CAZ.  Although since it is sealed combustion, it is probably not a big deal. 

 

I think a lot of programs will waive requirements to get a CO reading on the flue gases if the appliance is condensing and/or sealed combustion, and the flue vents out the roof and is not easily accessible. 

 

I'd agree w/ the previous post. When going for a worst case test, you only need to measure presssure difference in the CAZ WRT outside. I'm figuring you can get into the CAZ. If required, Measuring exhaust gas for CO and efficiency on a sealed appliance is done from the outside according to most, though several well known pro's will drill the PVC pipe and sample from there, then seal the pipe with fire rated caulk.   
Thanks folks. The culprit here is an older tankless that is not sealed combustion.

If the tankless water heater is not sealed combustion, then it could be either power vented (one PVC pipe), induced draft (inducer motor and metal pipe), or natural draft (with draft hood).  I am not comfortable drilling a PVC pipe to measure CO, but some will drill it and seal it with silicone caulk.  A metal pipe for an induced draft appliance can be drilled and plugged with a metal plug or taped with metal tape.  If it is natural draft, you can measure the CO by putting the probe down in the heat exchanger from the draft hood.

This is what we do:  The Standards are clear:  No air sealing, dense packing more than 15% of the shell area, duct sealing outside the thermal envelope, if you cannot complete the or combustion testing protocol.  So, if we cannot test all the appliances that might be affected by modified house pressures due to air sealing, than we don't recommend air sealing.  More accurately, we explain the issues on the work order and customer report.  If we get full access to the entire building, so we can create worst case conditions in all CAZ's, and we can test to the Standards, then we include air sealing on the work order (if apporpriate).   Also... yes, we've climbed ladders to take samples from flue gasses... but of course we prefer to drill and fill where allowed!

RSS

Home Energy Pros

Home Energy Pros was founded by the developers of Home Energy Saver Pro (sponsored by the U.S. Department of Energy,) and brought to you in partnership with Home Energy magazine.

Latest Activity

Susan Davison replied to Hal Skinner's discussion 'YGRENE' super fund for energy upgrade financing
"Hal,   With the above questions, let me first state 'let the buyer beware'. All of…"
32 minutes ago
Susan Davison replied to Hal Skinner's discussion 'YGRENE' super fund for energy upgrade financing
"Within California, there are multiple PACE programs available to consumers and business…"
50 minutes ago
Chris Dorsi added a discussion to the group International Home Performance Forum
Thumbnail

A Proposal for Expanded International Collaboration

This group was formed in conjunction with an article to be published in the May/June issue of Home…See More
1 hour ago
Sean Lintow Sr's discussion was featured

Blower Doors & Methods Used

Just curious - what Blower Door do you use, what tests do you do, and do you use software or…See More
1 hour ago
Dale Sherman's photo was featured

pressure house cutaway view

A cutaway view of most of the pressure zones measured with respect to (WRT) the adjacent space. A…
1 hour ago
Sean Lintow Sr's blog post was featured

http://thehtrc.com/2015/illinois-the-eri-the-iecac-resnet-the-final-push

Monday April 6th (10 AM to noon) will decide whether the ERI aka as the HERS option will be part of…See More
1 hour ago
Hannah Finch's blog post was featured
1 hour ago
randy tolowski's 2 discussions were featured
1 hour ago

© 2015   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service