31
Many codes will require the acidic condensate to be
neutralized before it can be placed in a drain system. A
neutralizer to control the pH of the liquid discharged to a
drain system is provided with every condensing appliance.
The neutralizer consists of an industrial grade, non-
corrosive plastic reservoir for collection of the condensate.
The condensate collects in the reservoir where it is in direct
contact with the calcium carbonate. As the reservoir fills, it
provides an extended residence time to neutralize the
condensate. The neutralized condensate exits from the
reservoir outlet. A ‘P’ trap must be installed upstream of
neutralizer see Figure 2 above. Prime the installed
assembly with water to prevent flue gas spillage from the
drain. Use standard ½" vinyl, PVC, CPVC or suitable hose
to run to floor drain.
When the condensate level in the reservoir rises to the
drain, the pH is controlled to a range of 6.2 to 6.5 before
exiting the system. (A pH of 7 is neutral. As the pH number
increases in numerical value, the relative acidity of the
discharge decreases). The neutralized condensate may
then be discharged into a suitable drain system without fear
of damage to the drain system. Always check with local
codes for specific requirements. Neutralizers may be used
in series to raise PH.
10.5 BURNER
MAINTENANCE
The burner should be removed for inspection and cleaning
on an annual basis. An appliance installed in a dust or dirt
contaminated environment will require inspection and
cleaning on a more frequent schedule. The fan assisted
combustion process may force airborne dust and dirt
contaminants, contained in the combustion air, into the
burner. With sustained operation, non-combustible
contaminants may reduce burner port area, reduce burner
input or cause non-warrantable damage to the burner.
Airborne contaminants such as dust, dirt, concrete dust or
dry wall dust can be drawn into the burner with the
combustion air and block the burner port area. An external
combustion air filter is provided with the appliance. An
additional filter is located at the fan inlet and like the
external filter may be washed in the sink under the tap. This
internal filter should be checked and cleaned at the time of
appliance commissioning and on a six month interval or
more often in a contaminated environment.
10.5.1
BURNER REMOVAL AND CLEANING
Access to the burner will require the following steps:
•
Turn off main electrical power to the appliance.
•
Turn off main manual gas shutoff to the appliance
•
Remove the top cover.
•
Disconnect the gas supply connection to the fan
inlet.
•
Disconnect the fan motor power wires at the
harness.
•
Remove the hot surface igniter and the flame
sensor.
•
Remove the sensing tubes from the air ratio gas
valve to the combustion air fan.
•
Remove the 4 nuts holding the fan assembly to
the heat exchanger and remove the fan assembly.
On occasion the red silicone gasket may adhere to
the underside of the fan’s flange. Carefully pry the
flange away from the gasket prior to removing the
fan assembly.
•
The burner can now be lifted vertically out of the
heat exchanger cavity. A ceramic paper gasket is
located directly under the burner flange. This
gasket must be replaced if it is damaged.
•
Use care to prevent damage to the knitted metal
fiber of the burner surface.
•
Wash the burner with low pressure water. Never
wipe or brush the surface of the burner.
•
Check all gaskets and replace as necessary.
Gaskets affected by heat will not reseal properly
and must be replaced.
•
Replace the burner in the reverse order that it was
removed. Insert the igniter and sensor before
doing the final tightening on the fan mounting nuts.
Evenly tighten the nuts to 20 ft-lbs.
NOTE:
When the combustion air fan is removed for any reason,
the inlet to the burner must be covered to prevent further
foreign objects from falling into the burner. Always look
inside the burner to check for dents. Do not place a burner
back into operation if the inner distribution screen has
been dented during the service operation, call the factory
for recommendations. Use care when removing and
handling the burner, Sharp objects or impact may damage
or tear the metal fiber surface rendering the burner unfit
for service.
10.5.2
BURNER CLEANING PROCEDURE
Remove any visible dust or dirt blockage from the surface
of the burner using water from a garden house. The
burner may best be cleaned by immersing the burner port
area in a solution of dishwashing detergent and hot
water. Do not use chlorine based solvents or cleaning
agents on the burner. Allow the burner to remain in the
solution for a short period of time to remove dust, dirt and
oil or grease laden contaminants. Rinse the burner
thoroughly with clean water to remove any residue from
the detergent cleaner. The burner should be air dried
after removal from the cleaning solution and rinsing.
10.6
CHANGING THE HOT SURFACE IGNITER
•
The hot surface igniter is to be checked at least after
every 4000 hours of operation and more frequently
under high cycling conditions. This will maintain peak
ignition efficiency.
•
Turn off main electrical power to the appliance.
•
Turn off main manual gas shutoff to the appliance.
•
Locate the Hot Surface Igniter.
•
Disconnect the two power leads to the hot surface
igniter.
•
Loosen and remove the two screws that hold the
igniter.
•
Lift the igniter vertically out of the burner mounting
flange. Use care, do not hit or break the silicon carbide
igniter.
•
Ensure that the ceramic paper gaskets used to seal the
base and top of the igniter are reinstalled on the new
igniter.
Summary of Contents for DFH500
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Page 39: ...36 PART 12 EXPLODED VIEW ...
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Page 46: ...43 PART 13 ELECTRICAL DIAGRAMS ...
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