Rigging Information
and Instructions
Seasons•4 Direct
Replacement Products
Seasons•4 manufactures Direct Replacement roof mounted HVAC units designed
to replace most units ever built. In addition to a replacement
expert having measured the existing units to provide our engineers
with the information they need to design the unit, with additional
rigging assistance also provided. The following instructions
are intended to describe this service and to assist our customers
with the installation of their units.
Rigging Assistance
Seasons•4 provides an experienced person to be on site with
the installer during rigging. When the "on site" date
approaches, we make arrangements for a person experienced in
installing replacement equipment to be at the jobsite when the
units arrive.
In the interest of maintaining good customer relationships and
addressing any unforeseen problems (old units weren't always
installed in accordance with their manufacturer's recommendations),
our Seasons•4 Representatives usually plan to be at the jobsite.
"RIGGING ASSISTANCE" includes advice on rigging (see
below), recommendations for solving unexpected problems uncovered
when the old unit is removed, and offering advice on the proper
location of the new unit on the existing curb.
Note! Seasons•4 personnel are
not responsible for the rigging; they merely offer advice. The
installing contractor or owner and their rigger are responsible
for properly rigging the units. The riggers are the experts
and must know the capabilities of their equipment and the proper
procedures for placing the units in the proper location.
Safety
It is imperative for the installing contractor to instruct all
personnel attending the rigging in proper safety procedures:
Under no circumstances shall any person stand below a unit being
lifted or removed. Be aware of loose pieces that may fall from
the old units.
Where it becomes necessary to reach under a unit to remove attached
ductwork, see below in the section on duct attachments.
If for any reason a person is required to place hands or arms
under a lifted unit supported by the crane, the contractor shall
insert wood blocks across each corner of the curb. Blocks shall
be of sufficient height, length and strength to maintain the
unit above the curb. Maintain tension on the lifting straps
while using blocks.
The contractor shall instruct personnel on the proper use of
hard-hats, and other required safety equipment.
The contractor shall adhere to all OSHA and code requirements
to insure the safety of the public and job-site personnel.
Preparation for Removal of Old Units
Prepare to remove the old units. Many old units have lifting
lugs which can be used to remove the units. Occasionally the
old lifting lugs will have been removed and new lugs or lifting
eyes will have to be provided by the contractor. Check this
prior to the arrival of the new units. Avoid the extra cost
of delaying the crane on the day the new units are to be rigged.
When lifting lugs are inadequate or missing, it will be necessary
to lift (by whatever means is appropriate) portions of the unit
to allow placing cables under the unit. Be very CAUTIOUS about
pieces falling off the old unit while it is being lifted.
Make arrangements for an electrician and a control technician
to be present during the removal of the old units. Power wiring
and control wiring (or tubing) must be properly handled to allow
using it with the new units.
The rigger must have a crane (or helicopter) with enough capacity
to lift the new units (and remove the old units which may be
stuck to the curb). Having a properly sized crane may seem obvious;
but, several times a year, we observe a poorly prepared rigger
attempting to lift a unit using an undersized crane. This results
in delays to obtain a larger crane or cobbling up some means
of adding additional counterbalances. Not only is this expensive;
it can also be dangerous. Seasons•4 submittals include the shipping
weights of the units. The rigger should always allow a minimum
10% safety factor to accommodate variations in rigging requirements
caused by unexpected jobsite conditions.
Disconnect the old unit's wiring, piping, etc.. Disconnect the
wiring from the old unit terminals. Do not cut the wiring. It
will be reused for the new units. Ducts must be loose prior
to lifting units.
CAUTION! The duct connection on most existing units is a simple
gasketed compression fit. However, some existing units have
their ductwork attached to the unit in such a way as to prevent
detachment while the old unit rests on the curb. Sometimes the
ductwork was screwed to the unit’s underside and it was
impossible to see this before the old unit was lifted. Also,
they didn’t always fasten all the ducts to the unit. Therefore,
the following precautions must be exercised:
The contractor shall instruct the crane operator to slowly and
carefully cable up when lifting the old unit. Lifting the supply
end first is suggested.
The contractor should assign a spotter at the supply air and
return air duct locations.
As the cable is lifting the unit, the spotters must immediately
communicate if the ductwork is tightly fastened to the bottom
of the unit (ducts rising with the unit). If the duct is fastened
to the unit, STOP the lifting immediately.
The contractor must determine the location, type, and extent
of attachments (may require more careful lifting).
When screws have been used to attach the duct, it will be necessary
to use a long-handled chisel and a hammer to break off the screw
heads. Sometimes it is possible to pry between the bottom of
the unit and the duct next to each screw head (shearing off
the screw head).
Every effort should be made to avoid cutting the flexible connections.
This will require rebuilding the duct prior to setting the new
unit.
Arrival of the New Units
The customer must inspect the new units for damage prior to
accepting the shipment and clearly describe any damage on the
bill of lading. Note: This inspection should include looking
inside the unit for damage. Do this before signing the bill
of lading and have the driver acknowledge the damage. Contact
Carol Johnson at Seasons•4 (770-489-0716) and report the extent
of the damage. Also, send a copy of the bill of lading to her
for use in discussions with the trucking company.
Find and remove the curb gasket material (and drive cleats and
duct angles when included) which is shipped in the unit (a label
on the unit tells the location). Send these items up to the
location of the unit being replaced. They will be needed when
the old unit is removed and prior to setting the new unit.
Preparation for Setting the New Units
The rigger should have proper rigging materials -- long enough
straps or cables, spreader bars, different sized shackles, and "scuff" blocks.
Note: Spreader bars (or cables a minimum of 40 feet long) must
be used to avoid damage to the new unit. Damage to the unit
during rigging is the responsibility of the rigger.
Seasons•4 units include multiple lifting lugs. Use them all.
The units must be lifted level. Adjust the rigging to provide
a level lift. If the unit is not level, it will be very difficult
to properly locate it on the existing curb.
Remove the old units. Scrape old gaskets from curb and ducts
to provide a clean surface for the new gaskets.
Make certain the old ducts are properly supported. If supports
are required for the old ducts, sheet metal angles included
with the new Seasons•4 units can be used. "S and Drive" clips
and angles will be included with the Seasons•4 units to provide
a flat surface to seal the old ducts to the new unit.
The seal between the old ducts and the new units is a compression
fit; therefore, the ducts must be properly supported and must
be flush with the top of the roof curb. The bottom of the Seasons•4
units is designed for the supply and return ducts to be flush
with the top of the roof curb. Install a layer of gasket material
around the curb and around each duct. Use two layers if necessary
to assure a good seal.
Some old units had the condensing section installed over a weatherproof
platform. Rubber/cork pads will be included with the new Seasons•4
unit to build up this platform to provide a level surface. The
Seasons•4 specialist can advise on the proper location of these
pads.
Rigging and Setting the Unit
Prepare unit for rigging. Remove shipping straps used to secure
access doors during shipment. If rigging straps or cables pass
in front of the control panel door or the return air compartment
door, open the doors prior to connecting the rigging. Access
to the inside of the control panel is necessary to guide the
power wiring into the unit during final setting. It is also
necessary to view the return air duct.
Check rigging. Spreader bars or 40 foot straps must be used
to lift the unit. Check to make sure lifting cables or straps
are clear of door handles and/or louvers. Use "scuff" blocks
if necessary to prevent damage to the unit. Lift the new unit
to the vicinity of the old unit's curb.
Remove the casing panel located under the zone damper control
access doors or on the sides of the unit to allow viewing the
individual zones prior to trying to set the unit on the curb.
If the new unit has a ducted return air connection, make sure
the access door to the return air opening is free of the lifting
cables or straps. Check to make certain that the control panel
door(s) is not blocked shut by the lifting cables or straps.
You must be able to open it when setting the new unit.
Lower the new unit to within a foot of the curb. Remove the
plate from the bottom of the wiring chase(s) and pull the power
and control wiring into the unit. Be careful to avoid "skinning" the
wiring and make sure it doesn't fall back down inside the curb.
Proceed with lowering the unit into place. Check duct alignment
(both supply and return air). Make adjustments to assure proper
sealing of the ducts to the unit.
Remove the rigging and replace the end panel used to view the
zone connections. Caulk the end panel to assure a weather tight
seal.
The unit is now ready for completion of the installation. See "Installation & Start-up
Instructions – Seasons•4 Products" included
with the unit.
|
|
