York DFAH - Manual (Page 33)

107272-UIM-B-1105
Unitary Products Group 33
SECTION XI: START-UP AND
ADJUSTMENTS
The initial start-up of the furnace requires the following additional
procedures:
IMPORTANT: All electrical connections made in the field and in the fac-
tory should be checked for proper tightness.
When the gas supply is initially connected to the furnace, the gas piping
may be full of air. In order to purge this air, it is recommended that the
ground union be loosened until the odor of gas is detected. When gas is
detected, immediately retighten the union and check for leaks. Allow
five minutes for any gas to dissipate before continuing with the start-up
procedure. Be sure proper ventilation is available to dilute and carry
away any vented gas.
PURGING
After the piping has been checked, all piping and appliances receiving
gas through the meter shall be fully purged. A suggested method for
purging the gas line to the burner is to allow the burner to cycle until
burner ignites. Do not purge by loosening gas lines. Under no circum-
stances shall the line be purged into the combustion chamber.
After the gas line to the conversion burner has been fully purged, the
gas supply at other pilot burners located on other gas appliances which
were extinguished as the result of interrupted service will need to be
reignited. Check all appliances to make sure the pilots are ignited.
CALCULATING THE FURNACE INPUT
(NATURAL GAS)
NOTE: Front door of burner box must be secured when checking gas
input.
NOTE: Burner orifices are sized to provide proper input rate using natu-
ral gas with a heating value of 1030 BTU/Ft
3 (3.6 m/m 3 ). If the heating
value of your gas is significantly different, it may be necessary to
replace the orifices.
1. Turn off all other gas appliances connected to the gas meter.
2. At the gas meter, measure the time (with a stop watch) it takes to
use 2 cubic ft. (0.0566 m
3
) of gas.
3. Calculate the furnace input by using one of the following equa-
tions.
CARBON MONOXIDE POISONING HAZARD
Failure to follow the steps outlined below for each appliance connected to the venting system being placed into operation could result in carbon
monoxide poisoning or death.
The following steps shall be followed for each appliance connected to the venting system being placed into operation, while all other appliances
connected to the venting system are not in operation:
1. Inspect the venting system for proper size and horizontal pitch. Determine that there is no blockage, restriction, leakage, corrosion or other
deficiencies, which could cause an unsafe condition
2. Close all building doors and windows and all doors.
3. Turn on clothes dryers and TURN ON any exhaust fans, such as range hoods and bathroom exhausts, so they shall operate at maximum
speed. Open the fireplace dampers. Do not operate a summer exhaust fan.
4. Follow the lighting instructions. Place the appliance being inspected in operation. Adjust thermostat so the appliance shall operate contin-
uously.
5. Test each appliance (such as a water heater) equipped with a draft hood for spillage (down-draft or no draft) at the draft hood relief opening
after 5 minutes of main burner operation. Appliances that do not have draft hoods need to be checked at the vent pipe as close to the
appliance as possible. Use a combustion analyzer to check the CO2 and CO levels of each appliance. Use a draft gauge to check for a
downdraft or inadequate draft condition.
6. After it has been determined that each appliance properly vents when tested as outlined above, return doors, windows, exhaust fans, fire-
place dampers and any other gas burning appliance to their normal condition.
7. If improper venting is observed during any of the above tests, a problem exists with either the venting system or the appliance does not
have enough combustion air (Supply Air from outside) to complete combustion. This condition must be corrected before the appliance can
function safely.
NOTE: An unsafe condition exists when the CO reading at the furnace vent exceeds 40 ppm and the draft reading is not in excess of - 0.1 in.
W.C. (-0.025 kPa) with all of the appliance(s) operating at the same time.
8. Any corrections to the venting system and / or to the supply (outside) air system must be in accordance with the National Fuel Gas Code
Z223.1 or CAN/CGA B149.1-00 Natural Gas and Propane Installation Code (latest editions). If the vent system must be resized, follow the
appropriate tables in Appendix G of the above codes or for this appliance.