How can we help?

You can also find more resources in our Help Center.

45 terms


% surface of wall that is framing lumber
ASHRAE recommended ACHn
solar heat gain coefficient of single pane glass
SHGC of 0.87
Saving potential from duct leakage per EPA
17% average
Saving potential from resizing per EPA
CO test failure for undiluted flue gas
100 ppm
Worst case CAZ limit WRT outdoors
-5 pa, except -2pa for atmospherically vented water heater, -15 pa for pellet stove w/ draft fan aand sealed vent. -50 pa for direct vent appliance
Worst case CAZ setup
Close exterior doors, windows, fireplace flues. Zero out base pressure, turn on dryer, exhaust fans, air handler (if hurts), open/close interior doors if hurts CAZ.
Worst case CAZ test process
Test smallest Btu appliance first, test spillage (mirror, smoke), test CO at SSE. If spillage after 1 minute, test under natural conditions.
Combustion efficiency measurements
Combustion analyzer: CO less than 100ppm, O2 b/t 6-9%, flue gas temp and heat rise per manufacturer.
Gas combustion system inspection
Look for soot, melted wires, rust. Inspect burners, heat exchanger. Check high voltage, test pilot safety circuit. Check heat anticipator, venting, high limit control (220 F limit). Measure gas input, open window to see if it reduces CO.
Gas system maintenance if
CO >100 ppm, visual signs of soot or flame rollout, burners dirty, draft inadequate, no service in 2 years.
Measuring Btu/hr input on gas systems
turn off gas appliances, fire unit being tested, clock one turn of gas dial, consult table (x1000). adjust to within 10% of furnace label (3.2-4.0 IWC)
Oil burner inspection
Check barometric draft control (unless high static pressure or mobile home burner). Inspect for soot, overheating, fire hazards, corrosion, wiring, fuel lines, heat/combustion chamber, instantaneous flame ignition (except pre-purge units)
Oil burner testing
Flue gas: O2, CO, SSE, smoke test. Over-fire and flue draft, high limit (250 F), oil pump pressure, xformer voltage, CAD cell (or stack control)
Oil burner adjustment
Match burner nozzle to heating load, oil pump pressure, air shutter (O2 and smoke values), barometric damper.
Oil burner maintenance
Clean blower wheel, burner assembly, replace oil filter, clean soot from combustion chamber/heat exchanger, check electrode gap, flame sensor. Redo diagnostics.
When is upgrading to a flame retention burner cost effective
if SSE is < 75%
Replacing oil burner protocol
size burner and nozzle to heating load. Install new combustion chamber or change nozzles to fit flame to chamber.
Testing ranges and ovens
test each burner separately (8" above flame), clean if > 25 ppm. Turn oven to high, sample after 10 minutes (undiluted < 100 ppm, ambient < 25 ppm).
Inspecting heat exchangers
look for rust at exhaust/vent area, flame damage/impingement, flame movement. O2 should change no more than 1% from off to on. Shine light.
common vent sizing
cross-section equal to largest vent plus 50% of smaller vent. No more than 7 times the area of smaller vent. Smaller connects below larger.
other vent rules
horizontal length no more than 75% of vertical length. no more than 18 inches of horizontal run per inch of vent diameter. 1/4" rise per 1' run
vent clearance
single wall 6" (gas) 18" (oil). B-vent 1" (gas). L-vent 9" or 1 vent diameter.
masonry chimney standards
supported by own foundation, lined with fireclay (1" air gap and unbonded to chimney), cleanout 12" below lowest inlet, penetrations sealed with metal/high-temp sealant. 2" clearance to combustibles
chimney terminations
Must have vent cap, 3' above roof penetration, 2' above any obstacle within 10' (ie ridgeline)
SSE 70+ characteristics
Cat I, draft diverter, no draft fan, standing pilot, non-condensing, indoor combustion and dilution air
SSE 80+ characteristics
Cat I, no draft diverter, draft fan, electronic ignition, indoor combustion air, no dilution air
SSE 90+ characteristics
Cat IV, no draft diverter, draft fan, low-temp venting, positive draft, electronic ignition, condensing heat exchanger, outdoor combustion air
pressurized sidewall venting requirements
Cat III, B-vent, stainless single wall or high-temp plastic. air seal joints with high temp caulk.
confined space CAZ definition
50 cubic feet of volume for every 1000 Btu/hr of appliance
net free area of metal vs. wood grills
60-75% vs. 20-25%
indoor opening to CAZ size
2 openings of 100 sq. inch minimum, 1 sq. inch per 1000 Btu/hr for each opening, combined room volume > confined CAZ specs
outdoor opening to CAZ size
2 vents, each 1 sq. inch per 4000 Btu/hr (2000 Btu/hr if ducted). If 1 vent, then 1 sq. inch per 3000 Btu/hr.
oil system emergency shut off should be located
in the living space
combustion furnance off/off settings
high limit 250 F or less. Fan on 120-140 F, fan off 95-105 F. Fan on within 2 minutes of ignition, fan off within 2.5 minutes of burner off.
combustion furnace airflow per Btu
11-15 cfm per 1000 Btu/hr. Plenum should have 2 sq. inches of cross-section per 1000 Btu/hr
Central AC airflow per ton
400 cfm +/-20% per 1 ton. 12,000 Btu/hr = 1 ton. 6 sq. inches of cross-section per 1,000 Btu/hr in plenum
BAS equation
CFM50 = 15 cfm x # of occupants (bedrooms +1) x n factor. Or CFM50= (.35 ACH50 x house volume x n factor)/60. Whichever is higher
N factor
Based on climate zone and building height, converts 50 pa airflow to natural airflow.
Shower flow rate measurement
time the filling of container with known volume. Low flow heas do 1.5-2.5 gallons a minute.
water heater energy factor
= Btuh coming out of water heater / Btuh put in water heater. Accounts for storage losses.
hot water efficiency increases from
reducing temp. to 120 F, reduce distance to fixtures, increase insulation, demand hot water circulation loop. If older dishwater w/o heater, keep at 140 F.
replacement gas water heater minimums
energy factor of 0.61 or greater and 2 inches or greater of foam insulation. 0.90 and 3 " for electric
water heater pipe insulation
insulate first 6' of hot and cold, keep insulation 6" from flue pipe.