Eternal GU145 (S), Operation Manual

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54
How To Check Gas Combustion
Procedure for high  ring
Unscrew the EC adopter cap on vent collar (see to above diagram) and connect the  ue gas analyzer.
Set to full load: with the unit at 130 ° F or higher, force the unit into high  re by opening demand of at least 7
GPM water  ow rate.
Wait 10 seconds for modulation to stabilize with the full-load fan speed, measure the CO level. It should not
exceed 200 ppm for both natural and propane gas.
Check the
 ame through the sight glass which should be stable with a regular  ame distribution.
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Setting procedure for low  ring
Set to low load: Turn dipswitch #3 in group 3 to ON and throttle demand down to no more than 2 GPM water  ow rate.
Wait at least 10 seconds for modulation to stabilize with the low-load fan speed, measure the O
2
/CO
2
percentage
and compare this to values in table 1.
If the values are not in accordance with the table then correct the gas/air ratio valve using the adjusting screw A
on gas valve.
If the value is too low turn the adjusting screw A clockwise; this increases the gas rate - if the value is too high
turn the screw anti clockwise which decrease the gas rate.
Flip dipswitch #3 in group 3 to OFF.
Cold
 ush the unit and let it take itself through at least 1 cycle on standby  re for boot up diagnostics.
Check the  ame through the sight glass which should be stable with a regular  ame distribution.
Reinstall the  ue stack cap when  nished testing.
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Only make small adjustments of the adjusting screw maximum 1/8 turns at a time when setting O
2
/CO
2
.
Ensure that the analyzing probe has a gas tight seal in the sampling point with the probe end in the centre of the  ue duct.
NOTE
! !
HOW TO CHECK GAS SUPPLY PRESSURE
Turn off power source and turn off gas supply to the unit.
Remove the front cover from the unit.
Loosen the gas supply pressure test port screw and connect manometer to this port; turn on the gas to the
water heater.
Turn the water heater on and open multiple taps to force unit into high
 re; check gas supply pressure at the
test port with a manometer with unit in high  re.
1.
2.
3.
4.
NOTE
! !
Manifold Gas Pressure should only be adjusted on low  re.
If gas supply pressure drops below 3.5" WC unit will not have enough gas volume for max  re!
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WARNING
! !
HOW TO CHECK MINIMUM MANIFOLD GAS PRESSURE
Check manometer reading of low  re manifold pressure against unit combustion speci  cations.
Turn the water heater ON with 2gpm of hot water  owing.
Set the dip switch group 3 and number 3 ON.
1.
2.
NOTE
! !
Note : During this procedure you will only observe the reading and will not make any adjustment.