Lanair DHI 300 - Manual (Page 18)

Section 6 - Fuel Supply Pump/Piping
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14. Install the fuel supply line from the fuel by-pass regulator (port B) to the inlet port on the
left side of the burner using 1/2” inside diameter (.493) steel pipe, or 1/2” outside diame-
ter copper tubing. The maximum distance of this line is 25 feet. The fuel supply line must
be run below the burner at all times. If the fuel supply line runs above the burner it will
create head pressure. This head pressure will over-fire the burner voiding the warranty.
15. Install a union in the supply line close to the burner for service.
16. Install a shut-off valve in the fuel supply line at the fuel by-pass regulator for service.
17. Use 37º flare fittings on all copper tubing connections. Do not use compression fit-
tings.
18. Keep the fuel supply lines 1” off any outside walls.
19. The fuel supply line must gradually rise to the burner. It should not be higher than the
burner.
20. Clean all lines, fittings, and parts internally before assembly. A small burr or piece of
rust could plug the nozzle. See Section 2 for an illustration of a typical pump and piping
installation.
B. Port to the oil inlet on the burner assembly.
Install 1/2” O.D. min. copper tubing, or 1/2”
schedule 40 pipe. Failure to install this line
properly will result in damage to your
heater, and will void your warranty.
T. Port to the oil supply tank for the overflow
return line. Install 1/2” O.D. min. copper tubing.
or 1/2” schedule 40 pipe. This line MUST run
straight into the tank, and should not be sub-
merged in oil. No elbows should be used.
Failure to install this line properly will result
in damage to your heater, and will void your
warranty.
P. Port from the outlet side of your fuel supply
pump. Install 1/2” O.D. min. copper tubing, or
1/2 schedule 40 pipe. Failure to install this
line properly will result in damage to your
heater, and will void your warranty.
Bottom View of the Aluminum Oil
By-Pass Regulator
Figure 4
Section 13 - Service / Maintenance
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35
Maintenance - Air Pre-Heater (cont.)
6. Clean all parts using a parts washer
• All passages must be thoroughly cleaned with a brush.
7. Replace Nozzle Assembly and Quad Ring
• After cleaning air pre-heater assembly, blow dry.
• Install new quad ring (4). Before inserting quad ring in air pre-heater block, a light coat
of oil should be applied. NOTE: Make sure quad ring is properly seated in block before
proceeding (see page 40 for clarification).
• Apply a light coat of oil to the shaft of the new nozzle assembly (3). Carefully insert new
nozzle assembly (3) through the quad ring and into the block and tighten securely.
• Check alignment of ignitors and adjust if necessary (see page 39).
8. Replace O-rings and Plunger
• Insert a new 1/4" o-ring (10) and a new 11/16" o-ring (11) into the air pre-heater
block (5).
• Insert new Viton insert (14) into the end of the plunger (15) and place new spring (13)
on the end of the plunger. Insert plunger into air pre-heater block spring end first.
9. Replace Cartridge Heater
• Apply pipe dope to cartridge heater threads. Insert cartridge heater into air pre-heater
block and tighten.
10. Replace Adapter Assembly
• Align the holes of the adapter assembly (16) with those on the air pre-heater block (5).
NOTE: Make sure the small end of the adapter pin is facing toward the air pre-heater
block.
• Attach the Adapter assembly (16) to the block using two hex cap screws (17). Tighten
screws.
11. Replace Diaphragm
• Replace diaphragm, o-ring and spring (see page 40) Hand tighten diaphragm assembly
to air pre-heater block. NOTE: Do not over tighten.
12. Replace Ignitor Assembly (see page 40)
13. Service Oil Pre-Heater (see pages 36-37 for Annual Maintenance Instructions)