Combustion Analysis and Safety Pt 2- BPI Review of 5 Point Combustion Testing

[@greentransmission]

Great video!! We prefer to test the smallest BTU appliance then set it to pilot and test the larger appliance by itself then refire the smaller appliance and check for spillage and draft. This tests each unit individually and then together. Also, there is one sentence in the BPI standards that calls for checking for spillage at the draft diverter of commonly vented DHW for an induced draft furnace upon firing.

[@brnmcc01]

This is correct, the International Fuel Gas code says for commonly vented Category I appliances (natural draft, non-condensing), the smallest appliance must be connected to the common vent at the highest level. This installation would not pass a code inspection here. Most states have similar rules that adopt the international code.

[@brnmcc01]

This is correct. The purpose of the inducer fan is to establish the draft on initial cold fire-up. Once the appliance is at stable operating temperature, the natural draft takes over, and actually overpowers the fan at this point and pulls the combustion gases thru the little squirrel cage. If you bypassed the pressure switch at this point (don't actually do this please), and shut down the inducer fan, assuming you have a good drafting chimney, it would actually continue to run just fine.

[@stevelewellen]

NIce video, thanks. Around the 3:08 mark you indicate the furnace is a an induced draft and that it can not back draft. Beyond the combustion point of view, there is sill concern of the draft is poor on the induced combustion equipment. Back draft is still possible. You can have roll out at burner level and back draft there. Or the possibility of back draft at the seams and gores of the vent and or vent connector.

[@thermal71]

So I'm really curious - where can I get the smoke gun? Is it really a kid's toy? Leave it to a toy company to get it right for a non toxic smoke gun for our industry! Great demonstration - so many how to vids stammer and stutter for words to describe these concepts and procedures, and understandably so - the stuff takes awhile to grab onto, and isn't easy to explain. This guy grooves right along and gets the point across very well. Thanks for a really helpful video.

[@MygreenKc]

The appliance with the smallest btu's is fired first. The furnace is then fired and spillage and draft re-checked at the water heater . Firing the furnace can cause the water heater to spill/ back draft.

[@UnboxFlix]

Great video. It looks as if some of the vent piping could use some aluminum tape at the slip joints.

[@HomePerformance]

@sienalaurel That's a great question- I only ever recommend using the 'Baseline' Function on a manometer (by pressing the 'Baseline' button) for a Blower Door test. You don't want to use it here, because it prohibits you from using that same manometer for zonal pressure testing during door closures to set up Worst. Baseline Function means the manometer is purposely lying to you- always better to record the baseline yourself, and do the math.

[@greentransmission]

There is a small amount of positive pressure right at the inducer fan but it is not a high static fan and this subsides quickly within a few inches of the fan as the heated flue gases creates a negative pressure as they draft up the flue pipe (hopefully). These are still atmospherically drafted appliances and rely on the buoyancy of the heated air to draft under small negative pressures.

[@Clevelandmarko]

Good job----------- My NCI class does not tell us to turn on ex fans to depressurize. It makes sence. I do that test when I do building sceince. When BPI the CO go to 25 PPM? In class, they told us 100 and lower is OK unless increasing and 400 OK on initial fire. I use the NCI Combustion charts. I am a student of Jim Davis. Where can I get the data that states 25 and under is good? What is BPI??

[@UnboxFlix]

Clevelandmarko no reply yet?

[@BruceTurnerHERSRater]

@PhillipBoldt91119 no the induced fan really just pulls combustion gases thru the heat excahnger this is still an atmospheric draft appliance. the fan has no significant effect on draft

[@renayesense999]

Hey George! Don't know if you'll ever see this but it's me, your ex-student, Renaye! Great to see you on here! Peace! (This guy's great, isn't he?)

[@marcoalvarez1276]

25 ppm of co in the stack seems impossible in the real world. Of course the lower the better but through research I was told you want to stay below 100 ppm of co in the stack. I would say maybe 10-20% of actual units in the field (even brand new) are above that 25ppm mark.

[@HomePerformance]

Not impossible. Plenty of pros test these units daily, and non-sealed combustion equipment can be held to higher standards. FYI, the 100 ppm mark is the new, more lax BPI standard, for years the standard was lower.

[@shielduniversity419]

My thoughts too

[@shielduniversity419]

Manufacturers say less than 100ppm

[@gregghavens4142]

Thank God most new units are sealed combustion these days

[@zuzilda]

How to install COMBINATION SPACE HEATING/POTABLE WATER HEATING SYSTEM? Or heating system attached to water heater, and using hot water to heat the house??? I am looking for anything for sale for this or instructions. Thanks!

[@danstheman3]

@thermal71 google "chimney balloon" and "smoke pencil pro" They finally made a more professional looking version. This one is also a lot more compact, I like it. It costs $30. (No affiliation, just a fellow professional)

[@TassoD1]

NYS FUEL GAS CODE 2010 Chapter 5 - section 503.10.4 page 87 .

[@metspride21]

bpi is building performance institute , check it out at bpi.org

[@walterluna880]

aluminum tape on flue is that code

[@GFKopf]

Great videos! Super helpfule!

[@algorithmical]

I see 57 likes and 2 people who failed the field exam.