Bearings; Fall; Start-Up; High Limit - Greenheck VSU Installation, Operation And Maintenance Manual

Bearings

The bearings for the fans are carefully selected to
match the maximum load and operating conditions
of the specific class, arrangement and fan size. The
instructions provided in this manual and those provided
by the bearing manufacturer will minimize any bearing
problems.
IMPORTANT
Lubricate bearings prior to periods of extended
shutdowns or storage and rotate shaft monthly to aid
in corrosion prevention. If the fan is stored more than
three months, purge the bearings with new grease
prior to start-up.
Recommended Bearing Lubrication Schedule (in Months*)
Bearing Bore Size (inches)
Fan
RPM 1 ⁄ - 1 1 1 ⁄ - 1 1
2 8
750 6 5
*Suggested initial greasing interval is based on 12 hour per
day operation and 150°F maximum housing temperature.
For continuous (24 hour) operation, decrease greasing
interval by 50%
• If extended grease lines are present, relubricate while in
operation, only without endangering personnel.
• For ball bearings (operating) relubricate until clean grease is
seen purging at the seals. Be sure not to unseat the seal by
over lubricating.
• For ball bearings (idle) add 1-2 shots of grease up to 2 in.
bore size, and 4-5 shots above 2 in. bore sizes with a hand
grease gun.
• For roller bearings add 4 shots of grease up to 2 in. bore
size, and 8 shots for 2-5 in. bore size with a hand grease
gun.
• Adjust re lubrication frequency based on condition of
purged grease.
• A high quality lithium based grease conforming to NLGI
Grade 2 consistency, such as those listed here:
Mobil 532 Texaco Multifak #2
Mobilux #2 Texaco Premium #2
32 Model VSU Make-Up Air
⁄ 1 5 ⁄ - 1 7 ⁄ 1 15 ⁄ - 2 3 ⁄ 2
2 8 8 16 16
4 3
B Shell Alavania #2
Exxon Unirex #2
Maintenance - Fall

Start-Up

Repeat the information as outlined in:
• Start-Up - Blower (page 14)
- Air Volume Measurement and Check
• Start-Up - Direct Gas (pages 15 and 16)
- Check the Supply Gas Pressure
- Check the Pilot Gas Pressure
- Check the Optional High and Low Gas Pressure
Switches
- Set the Burner Air Pressure Differential
This will ensure that the gas and air are set properly
before the heating season begins and should lead to
trouble free operation all winter.

High Limit

The high limit switch may have tripped over the
7 ⁄ - 3
16
summer; it should be checked and reset if necessary.
3
Burner
Inspect the burner for accumulation of scales on both
the upstream and downstream sides of the mixing
plates. Any scaling or foreign material should be
removed with a wire brush.
Visually check that all holes in the mixing plates are
clear. If any burner ports are plugged (even partially),
clear them with a piece of wire or another appropriate
tool.
Replace or tighten any loose or missing fasteners on the
mixing plates. Always use zinc-plated or stainless steel
fasteners.
Inspect and clean the flame and spark rod. Occasional
replacement of the flame rod and spark rod may be
necessary to ensure optimum unit performance.
Do not enlarge burner ports when clearing a blockage,
performance could be affected.
Flame rods can last many years, but because of
thermal expansion of the porcelain, flame rods can fail
over time.

Gas Train

The gas connections, joints and valves should be
checked annually for tightness. Apply a soap and water
solution to all piping; watch for bubbling which indicates
a leak. Other leak testing methods can be used.
WARNING
NOTE
®