Seems pretty elementary doesn't it?  What should be a simple safety check on fossil fuel burning appliances, particularly for boilers with regards to ease of inspection, often is assumed with complacency or even goes unchecked.  I know everyone's maintenance schedule is packing up in the Northeast with the cold snap this week, so Technicians Take Heed!

There are many indicators that should trigger the phrase: "Check the flue!"  I always measure the draft in the flue of a natural draft, 80% appliance.   Too high or too low of a draft both can be an issue.  HVAC Contractors tend to focus on the 'too little draft' by installing chimney liners, completing Combustion Appliance Zone and CO testing.  Of course this condition could be the most dangerous, so I can't blame them.  Who ever expects to pull the flue off the boiler, look into the chimney and see what is pictured?  There must have been 40 years of garbage piled up!  Really is a spectacular thing that after all the years of maintenance I have yet  to become complacent with the Flue. 

Did you know the draft of the chimney is very dependent on the temperature difference between the flue gas and outside.  The greater the temperature difference, the better the draft (generally speaking).  This means the draft may be just fine on a cold WInter night, yet spill gases on a warm Fall afternoon.  Conversion warning: 25 Pascals = .10" w.c.  I know: metric, really?...Trust me, the rest of the world has the real gripe when they see standard measurements.  I bet your electronic manometers or even magnahelics (whatever you are using for draft measurements) have this scale.  Take a look at this chart supplied by Building Performance Institute (T_Out is your Outdoor Ambient Temp), start testing, and be sure that boiler will be safe all year long.  Oh, and don't forget about the water heater too!

 

 

BPI.org

The draft was just fine on this older, larger than most boilers (-.03"w.c.).  Except how long before that chimney became a real problem?  I have to tell everyone: I have found birds, nests, even a squirrel in a 90%+ flue.  Yes, that was a rotting mess to cut through with a hacksaw in a half-finished basement.  Always test the draft, measure the CO, and look into the flue/chimney.  You may just be surprised one day; possibly save someone, or maybe a home!

http://excessair.blogspot.com/2013/09/check-flue.html

Views: 925

Comment

You need to be a member of Home Energy Pros to add comments!

Join Home Energy Pros

Comment by Bob Blanchette on October 8, 2013 at 4:46pm

ALL dryers should have the duct checked annually. Electric dryers will set the lint on fire if the heating element doesn't burn out first.

Comment by Dennis Heidner on October 8, 2013 at 3:23pm

Good article..

If the homes have a natural gas dryer - check the flue -- in this case the vent line is as important.  Long drying times are symptons of a clogged dryer vent... and when its natural gas -- that means the flue is not operating efficiently.  

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

Hal Skinner added a discussion to the group HVAC
Thumbnail

Old ductwork efficiency file

Allison,found the attached file on ductwork efficiency on an old CD I made.  Its definitely dated. …See More
27 minutes ago
Hal Skinner posted a discussion

What an RCC can do with no R- insulation in the walls.

I have had a handful of folks on this forum tell me, in effect,  that an RCC can do a very good job…See More
1 hour ago
Trip Smith posted a discussion

Where to spend my marketing dollars?

Hey everyone, I'm a new home performance company owner. (Originally a general contractor who is…See More
2 hours ago
Profile IconManuel Gutierrez, Chris Baker, Sharon Cannizzo and 1 more joined Home Energy Pros
4 hours ago
Kevin Jordan replied to Kevin Jordan's discussion air infiltration total
"thanks.  but it was just an illustration of a hole 2x2 with money going out of that…"
7 hours ago
Tom White posted a video

Adaptive Thermostats Demonstration Results Installed at UC Davis 6/26/2014

In buildings where variations in occupancy would fool a standard programmable thermostat, new adaptive thermostats have potential for significant energy savi...
10 hours ago
Hal Skinner's discussion was featured

Has Lead Based Paint ever stopped you on an energy upgrade?

In the process of determining all the different things that a home energy rater suggests to a…See More
10 hours ago
George Kopf's 2 discussions were featured
10 hours ago

© 2014   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service