Energy Tech Laboratories DHG240 - Manual (Page 26)

035-17233-000-C-0702
26 Unitary Products
1. Remove the burner assembly as outlined in BURNER
INSTRUCTIONS.
2. Remove the roof over the gas heat section.
3. At the top plate from the top draft blower housing and the
top draft blower wheel.
4. Remove the screws holding the top of the flue collector
box. Carefully remove the top of the flue collector box
without ripping the adjacent insulation. Then remove the
center divider plate separating the upper and lower flue
boxes.
5. On the inside of the flue collector box, remove the flue
baffles from the tube interiors. Note the last bend of the
baffle fits tightly against the tube forcing the end of the
baffle to lock into the tube collar. This collar is formed
when the tube is expanded into the end sheet. To
remove, move the end of the baffle toward the center of
the tube releasing the end of the baffle from the tube col-
lar, then pull straight out of the tube. Refer to Figure 20.
6. Using a wire brush on a flexible wand, brush out the
inside of each heat exchanger from the burner inlet and
flue outlet ends.
7. Brush out the inside of the flue collector box and the flue
baffles.
8. Run the wire brush down the vent hoods from the flue
collector end.
9. If soot build-up is particularly bad, remove the vent motor
and clean the wheel and housings. Run the wire brush
down the flue extensions at the outlet of the vent hous-
ings.
10. After brushing is complete, blow all brushed areas with
air or nitrogen. Vacuum as needed.
11. Replace parts in the order they were removed in Steps 1
through 4.
12. When replacing the center and top of the flue collector
box, be careful not to tear the adjoining insulation.
13. Ensure that all seams on the vent side of the combustion
system are air tight. Apply a high temperature (+500°F)
sealing compound where needed.
TROUBLESHOOTING
NOTE: To find the Btu input, multiply the number of cubic feet
of gas consumed per hour by the Btu content of the gas in
your particular locality (contact your gas company for this
information - it varies widely from city to city.)
FIGURE 21 : TYPICAL FLUE BAFFLE INSTALLA-
TION
Troubleshooting of components necessarily
requires opening the electrical control box with the
power connected to the unit. Use extreme care
when working with live circuits! Check the unit
nameplate for the correct line voltage and set the
volt meter to the correct range before making any
connections with line terminals.
Prior to any of the following maintenance proce-
dures, shut off all electric power to the unit to pre-
vent personal injury.
Label all wires prior to disconnection when servic-
ing controls. Wiring errors can cause improper and
dangerous operation. Verify proper operation after
servicing.