Does anyone have an inexpensive method to "clock" a combustion furnace to estimate BTU output similar to Natural gas, but for propane, kerosene, or oil? I work in the Weatherization Assistance Program and often the nameplates are missing from existing furnaces. Without BTU output it is tough to do an accurate computer model of the home. Thanks!

Views: 460

Reply to This

Replies to This Discussion

For natural gas, run only the furnace for a given time, mark the dial difference on the meter and multiply the gas used by the heat multiplier for your gas supplier. This will give you a ball park estimate.

For propane, you can look at the burner orfice size.  there are charts that give the btu rating for the orfice size. then multiply by the numbers of burners.  will give approx output.  LP orfices are usually slightly smaller btu than Nat. ones.

Follow the link

http://www.joppaglass.com/burner/lowp_chrt.html

Thanks for all the comments plus the link. I think based on them I have enough information forfollks in the field to get close enough to the correct size furnaces for modeling the houses thanks all.

Ernst,

You mentioned oil, but the replies seem to all be for gas, unless I didn't read correctly.  For oil you can look for the nozzle size.  Sometimes it is notes on the service tag or in the manual, if still around.  In some cases you might be able to call the service company as they may have that noted for their HDD fuel calculations or service work. 

Bud

Thanks, I did find that out. In weatherization we deal with some really old furnaces, so sometimes getting a ballpark furnace size is the best we can do but the nozzle sizes for oil seem to be pretty specific.

For the oil burning furnaces, you should check the pump pressure. Older furnaces run at 100psi, and newer ones run at 140psi. When the pressure is higher, you need to cross reference the nozzle size to get proper Btu ratings. Plenty of reference materials are located on the Beckett website.

For propane figure about 20-25k per burner rated input. Varies some form unit to unit but 22k is typical.

Thanks Bob, we'll go woithout. It should be close enough without having to factor in pressures and temps, etc and  complicate the process too much.

I'll apologies in advance for drifting here a bit, but your "close enough" comment threw me back to my beginning in this business (05) when I questioned every number we use.  The idea of pinning down the performance of a home to the last tiny detail is laughable when we consider just how many of our inputs are "close enough" numbers.  From insulation values, HDD, window performance, and air leakage (to name a few), we guess and we guess and then carry our calculations out to two decimal places (or the computer does).  I think my tape measure is the only real source of accurate information :).

I enjoyed the comment

Bud

RSS

Videos

  • Add Videos
  • View All

Twitter

Latest Activity

Paul Raymer posted an event
Thumbnail

MA Crew Chief/BPI Building Analyst Training at Bristol Community College at Commonwealth Landing

September 12, 2016 at 9am to September 16, 2016 at 4:30pm
Bristol Community College has created a hands-on training cabin in their laboratory.  This class…See More
1 hour ago
Daniel Morrison replied to John Nicholas's discussion Slab Edge Insulation - A Side Thread to Melissa's Question
"John, I just collaborated with Steve Baczek on a few videos for ProTradeCraft about slab insulation…"
9 hours ago
Profile IconMichael Sumpter and Bill Gartner joined Home Energy Pros
yesterday
Malcolm Jackson 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
yesterday
Amber Vignieri liked tedkidd's discussion What if more efficient homes were actually worth more?
yesterday
Amber Vignieri posted a blog post
yesterday
Eric Kjelshus replied to Rob Madden, Solar Home Broker's discussion Indoor Air Quality Monitors and Meters
"I have been using air advice for 5 yr or so - I end up with a report in 35 min I can e-mail or show…"
yesterday
Profile IconShane Matteson, Jay Cooper and Mike Harris joined Home Energy Pros
Thursday

© 2016   Created by Lawrence Berkeley National Laboratory.   Powered by

Badges  |  Report an Issue  |  Terms of Service