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: 29

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

Mike Kandel added a discussion to the group Building Performance Institute (BPI)
Thumbnail

BPI's Home Energy Auditing Standard Published as ANSI Standard

The Building Performance Institute, Inc. (BPI) is proud to announce that BPI-1100-T-2014: Home…See More
2 hours ago
Mike Kandel posted a discussion

BPI's Home Energy Auditing Standard Published as ANSI Standard

The Building Performance Institute, Inc. (BPI) is proud to announce that BPI-1100-T-2014: Home…See More
2 hours ago
Hal Skinner posted a discussion
2 hours ago
Todd St.Clair joined allen p tanner's group
Thumbnail

Energy Auditing Equipment for Sale, Trade or to Purchase

Discuss the pros and cons of the equipment you are interested in prior to purchase. Post equipment…See More
5 hours ago
Todd St.Clair replied to Jim Falakos's discussion Treat Software in the group Energy Auditing Equipment for Sale, Trade or to Purchase
"How long ago did you buy this, if it was good for 5 months? And how much would you take for this."
5 hours ago
Bud Poll replied to Bud Poll's discussion Basing air exchange on house volume??
"Hi Sean, yes I am struggling with this and that is why I opened the discussion, so a definite…"
7 hours ago
Lynda Wright is now a member of Home Energy Pros
7 hours ago
Sean Lintow Sr replied to Bud Poll's discussion Basing air exchange on house volume??
"Sorry Bud but I think you need to clarify your issues with using volumes to calculate ACH As for…"
18 hours ago

© 2014   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service