A Div of DH SATELLITE Inc.
“DH SOLAR TRACKER” INSTALLATION MANUAL
BOLT TOGETHER FRAME
Some history of this product. We began spinning parabolic aluminum antennas in
1980 with our 5 meter commercial antenna and tracking mount. We have sold thousands
all over the world to TV stations, cable companies and other commercial users to receive
satellite signal. This tracking system worked so well that we have used the same
mounting system with a sun tracking controller and framework that allows us to attach
solar panels and track the sun. It’s proven in the field and we know how well it works. The DH solar system tracks the arc of the sun returning each evening and adjusting itself
to match the changing arc as we change season and go from longer to shorter and then longer
days.
www.dhsolar.net 600 N Marquette Rd
Prairie du Chien WI 53821 ph: 1-608-326-8406
email: [email protected]
We update our manual periodically.
Last Revised 10-25-16
WARNING TO INSTALLER AND/OR ELECTRICIANS
• Please read the instruction manual completely.
• Please be familiar with the National Electrical Code and their requirements for
solar electrical installation.
• Failure to ground the tracking system may result in damage from lightening.
• Install ground rods according to NEC specifications to properly ground the
system.
WARNING! Failure to install the tracking system to the manufacturer’s specifications will cause tracker to malfunction and may cause serious injury or even death. This tracker system moves throughout the day, therefore no objects should be placed near the system.
KEEP CHILDREN AWAY FROM TRACKER AT ALL TIMES!
WARNING! If an alternate DC device is used to move the tracker motor, YOU MUST Disconnect the wires on the Motor that are connected to the Controller. Failure to disconnect these wires will result in the Controller circuitry to fail!
Warning
VERY IMPORANT! NEVER LOOSEN THE CHAIN ON THE HORIZON FRAME UNLESS INSTRUCTED TO BY DH SOLAR PERSONNEL. It is the installer’s responsibility to ensure that the chain is tight when the system is checked over before being put into service.
DH Solar Tracker Maintenance Schedule
Your new DH Solar Tracker does require some maintenance periodically to keep it running efficiently. When our solar trackers leave our production facility, we have the chain tightened for the application of its use. With all new chains, they tend to stretch as they are first used on a regular basis. To ensure that your chain does not slip off from normal stretching, we require it to be checked during the first year as that is the most critical time it may stretch. Failure to abide by the maintenance schedule may result in your solar tracker to not run as it was intended to, and the chain may slip off of the hoop. Never loosen the chain, unless DH Solar personnel instructs you to! Calendar Action to perform on the system First month of operation Check chain for snug against hoop Second month of operation Check chain for snug against hoop Third month of operation Check chain for snug against hoop Fourth Month of operation Check chain for snug against hoop Fifth month of operation Check chain for snug against hoop Sixth month of operation Check chain for snug against hoop Lubricate chain and sprockets with chain lubricant * Eight month of operation Check chain for snug against hoop Tenth month of operation Check chain for snug against hoop 1 year of operation Check chain for snug against hoop Lubricate chain and sprockets with chain lubricant * Check all nuts and bolts for tightness on system After 1 year of operation Action to perform remaining life of system Quarterly checks on system Check chain for snug against hoop Twice a year on system Lubricate chain and sprockets with chain lubricant *Yearly or every other year Check all nuts and bolts for tightness on system *If you live in a dusty environment, a dry lubricant may be used in lieu of a liquid*
Explanation of actions Checking chain for snug= The chain on the horizon should not be able to move more than an inch or two from side to side. This is crictical in the first half year of operation and the chain may stretch. Checking nuts/bolts= During installation, all of the nuts and bolts should have been properly tightened. Over time, nuts may loosen up a little due to normal movement and also weather conditions. It is best to check over them to ensure they are still tight.
Thank you for purchasing a DH Solar Tracker! These installation instructions will help
guide you through putting the pieces together. Please familiarize yourself with all the
components and read through the manual completely before beginning installation.
Components
Base Pole Base Can Horizon Mount
Green Washers 8-5/8” U-bolt 2-1/2” U-bolt Panel Plate Plate
Page1
You will need a boom truck, crane, or some sort of machinery that can lift up the heavier
components up to the top of the base post. When assembling the main framework, it is best to lay it
out on a set of sawhorses as it will be easier to adjust the pieces of steel. You may, however,
assemble all of the main framework up on the pole.
Controller
Actuator
www.dhsolar.net
Modules (optional)
Inverter (optional)
Bushings
(Optional) This plate may be included with your system depending on
your manufacture of modules. These plates will be used to mount the
outer panels and the ones adjacent to them on the same plate as the holes
are offset from one another. 4 Hole mounting plate
Installing Base Post
2.1 Remove nuts from J-Bolts & pry off the wooden template.
2.2 Next, set base post so the holes align with the J-bolts, then fasten the j-bolts with the
provided nuts.
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OPTIONAL INVERTER RACK: If your tracker came with an inverter rack
and you plan to use it to mount the inverter and controller on the post, follow
these instructions:
-Locate the inverter rack
-on the North side of the base post, lift the inverter rack up and line up the two
tabs of the rack with the two tabs of the base post and insert a ½” x 1 ½” bolt
through each tab and fasten with a washer and nut.
- Locate two bent braces and attach them to the side of the inverter rack and the
side tabs on the base post with ½” x 1 ½” bolts, washers and nuts. There will be
two braces per side of the inverter rack.
The controller mounting position is on the upper left hand corner, where the 4
holes are located.
Tabs of inverter rack aligned with tabs
on base post, bolts through them
Bent Braces
Tabs on inverter rack
Once the Horizon frame is set, you will want to strap the frame to the base post so it doesn’t pivot
upwards.
4. For this next step, you will need a flat area or trailer to assemble the “H” portion of
the main frame.
Set Screws
Tighten as instructed,
Remember you must
tighten all the way after
installation is complete.
Notice the placement of the bolt
through the front of the boom
and location of the Elevation
Adjustment
Page 3
3a. Raise the horizon mount and boom up and slip over the base post. Tighten
the set screws slightly to prevent the frame from moving while assembling. See
photo to the right. YOU SHOULD NEVER LOOSEN THE CHAIN ON THE
HORIZON FRAME UNLESS INSTRUCTED TO BY DH SOLAR PERSONNEL.
3. Attach the Horizon to Horizon to the base can by inserting a ¾”x7” bolt
through the front of the boom as shown in the photos.
4a. The first piece to fasten will be the middle 2x6 piece
that is 49” long. The tab should face up. Bolt the 2x6 to
the 77” 2x6 as shown in the drawing.You will be using
½”x3-1/2” bolts and a 6”x6” metal plate on the outside of
the 77” 2x6. The bolt heads should both be on the outside
of the 77” 2x6 and the 6x6 plate.
4b. Next, Lay the 2 long 2x6’s(roughly 19’-6”) on their
side, one up from the 77” and one down from the 77”. Lay
the 77” long 2x6’s that have the TAB welded to them as
shown in the picture to the left. Bolt the 77” long pieces to
the long 2x6’s with (4) ½”x3-1/2” and a 6”x6” plate on
the outside of the long 2x6’s. All the nuts should be
fastened so they are on the inside of the framework.
Picture 3
5. Once you have tightened all the bolts on the “H” Frame you are ready the lift the assembly up on the Horizon Mount.
Below are some pictures to illustrate this process. You can skip and come back to this step if you want to assemble all
of the framework on sawhorses. You will then need to come back to this step.
6. The next steps will be installing the 2x2 uprights on top of the 2x6’s. You will need to know your panel dimensions
and the hole placements on the panels for fastening. You will be using the 8-5/8” U-bolts to attach the 2x2’s to the
2x6’s and the panel plates will be secured to the 2x2’s with the 2-1/2” U-bolts.
6a. You will need to find and mark the center of the long 2x6’s between the “H” frame. This will be your starting
reference point. At this center point, the center 2 panels will meet. To do this, put one of the long 2x2 pieces up on top
of the 2x6’s. Next, take one of the panel plates and hand tighten it with a short u-bolt to the 2x2. If you are working
from the bottom of the frame, you will want the plate to face left. Slide the 2x2 over so that the middle of the panel
plate’s two holes is centered in line with the mark you made.
6b. Very important! You need to make sure that the 2x2 overhangs the 2x6’s evenly on both the top and bottom. For
our Suntech panel layout, we have 37” of the 2x2 above the “H” frame and below.
5a.You will need to line up the 2 tabs on the uprights with the holes on
the Horizon Mount.
Very Important! You must insert brass bushings in each tab hole
before you insert the bolt and green washer! (See Photos below)
5b.You need to insert a Green Washer in between
the tabs on the H and the Horizon Mount. Insert
the 1”x 3 ½” bolt and hand tighten in hole.
Note: You will want to lift the frame from the top(closest part
with the actuator tabs) with a boom truck, or similar device, up to
the Horizon Frame
5c. Once you have inserted both bolts, lay the frame back
with your boom and tighten the two bolts going through the
frame and green washers. *Very Important*—DO NOT
OVER TIGHTEN THE BOLTS GOING THROUGH
FRAME & GREEN WASHERS, TIGHTEN THEM
ONLY TO SNUG FIT WITH A WRENCH. THIS IS A
PIVOT POINT.
www.dhsolar.net Page 4
Tab
Horizon Frame
Horizon Frame
Green Washer
Frame Tab
Brass Bushing
Bolt
Actuator
Tab
www.dhsolar.net Page 5
The picture on the left is
the panel plate and also
shows a white line which
represents where the
panels will meet on the
plate. The white line is
centered on the 2x6. The
oval holes are used to
secure the panels.
6b. Once you have found where the two center panels will meet, secure the 2x2 to each of the two 2x6’s with two 8-5/8” U-bolts
and a square plate as shown in the illustration to the right. Notice the picture above right, your centerline white mark on the 2x6
should be between the two mounting holes on the panel plate. Once you have line it up, fasten the U-bolts to both the 2x2 to the
2x6. Be sure that before securing the 2x2 that both ends are squared up.
6c. Once you have the 2x2 secured to the 2x6’s, you will need to measure out the hole placements on the back of your panels. You
will want to measure the side holes(Our Suntech panels measure 37” apart). Once you have the measurement you will know how
far apart the next panel plate will need to be. Since our panels holes were 37” apart, we put the next 2x2 37” apart based on the
panel plate’s slotted holes. If you are figuring out the middle left panels first, remember that the holes on the panel plate nearest to
the U-bolt holes will be used. See Illustration below.
6d. When you have two 2x2’s in place you will want to lightly attach panel plates to them for the center panel. Move the
plates up or down on the 2x2’s to line up the mounting holes. On Page 6, there is a diagram of a 16 panel layout and where
the panel plates are located. These are for Schott panels only!! You will need to figure out the spacing if you are using
another manufacture’s panels. This is shown for reference only!
6e. You will notice on the far right 2x2 that the panel plates are facing the opposite direction. This is done so there is room for
adjustment on the 2x6. Since the plates are facing the other way, the distance from the previous 2x2 to this one will be less.
6f. If you assembled the framework on the ground, you will want to go back to Step #5 for instructions to lift the framework
onto the horizon mount. If you assembled the framework on the horizon mount already, then continue on to Step #7.
2x6
2x6
2x2
U-Bolts
Plate
Panel Plate
The Powered Declination will adjust
for the seasonal change that the sun’s
arc makes from the longest to the
shortest and back to the longest day.
Page 6 www.dhsolar.net
7. The basic DH Horizon to Horizon mount has a powered declination adjustment. You will, after
the main structure is assembled, attach the powered declination as shown here in these photos. This
will adjust for the seasonal change that the sun’s arch makes from the longest to shortest day.
IMPORTANT: Pictures on this page
showing how to configure the actuator
arm. You must move the collar up
towards the top by the rubber boot and
may need to rotate the clamp so the
motor is on top of the actuator when
installed. Then you must pound out the
brass bushing in the mounting hole so a
¾” bolt will fit through it.
Bushing inside
that needs to be
removed.
THIS IS A LAYOUT FOR Suntech 210w 16 PANELS ONLY!, YOUR PANELS’ LAYOUT WILL VARY!
Actuator must be installed as shown
in this picture. The motor needs to be
on top as any moisture can drain
through the weeb hole.
Also, it’s very important to tighten
the clamp
Rubber Boot
Notice the clamp is
fastened just below
the rubber boot. Be
sure to tighten the
clamp once it is
below the boot.
Page 7
7.1 After the power declination actuator is on, take the
turnbuckle and extend it out. You will then attach the
turnbuckle from the Horizon frame to the tab on the base can.
(As shown in the picture to the right) Once you have the
turnbuckle installed, you can adjust it to lay the frame back so it
is easier to install the solar panels.
You are now ready to put panels on.(See additional photos
below) Remember to install grounding wire under each panel
and ground according to the National Electrical Code
Panel placed on panel plates Underside of frame, Notice the hole placement
of panel compared to panel plate hole.
8. Finishing the Installation/Aligning South
Once the panels are on you will need to tighten all of the nuts and bolts including the frame, mount, and panels. You
will need to align the panels so they face magnetic south. There is a chart in the back of this manual to help you. Be
sure to tighten the set screws on the base can to the pole. This step is important as you do not want the can to pivot
on the pole and get out of alignment facing south. Failure to tighten the set screws may result in your system pivoting
on the pole and damaging your panels as they may hit the ground.
Another very important step that must be done to the system is Grounding.
The structure itself must be grounded. In the picture below are the spots where a grounding clamp must be place and
ground wire ran continuously to each point. The pole must also have a grounding clamp on it as well. See page 13 of
this manual for grounding tips.
Setting the tracker to your latitude
Once the bolts are all tighten, you will need to set the tracker to your site’s latitude. You will need an angle finder for
this step. Our home site, in Prairie du Chien, WI, is 43 deg. Latitude. You will have to find out your own latitude.
To set the tracker to latitude, make sure the tracker is still facing South. You will then need to adjust the turnbuckle
until the boom is set to your latitude angle. To find the angle, place the angle finder on the boom’s top, which is right
above the can. See photo on top of page
When you have finished, you are now ready to proceed onto the next steps in this manual.
Warning: Failure to set the tracker to your latitude will result in the tracker not be aligned correctly. An
incorrect alignment may result in the tracker to not be as efficient as it is intended.
Place Angle
Finder Here
DH SOLAR CONTROLLER INSTALLATION
Your DH Solar Tracking unit has a controller which runs the unit automatically. Follow these steps to install the controller correctly.
1. The cover of the controller is held on by 4 phillips screws, remove these screws to
access the inside of the controller. Once inside the controller, locate the 4 mounting
holes. You will need to fasten the controller with 4 small bolts and nuts(See Figure 1). It
is best to install the controller next to the tracker.
Figure 2
2. Locate the power supply. Under the power supply
are two AC terminals & a Ground. Insert a “2 wire
w/ground” power cord into the grommet on the
bottom of the controller box and insert the two AC
and GND. You will need to insert a small flat blade
screwdriver into the slots, insert the wires, and then
release the screwdriver.
Figure 1
Mounting Holes
Insert a small screwdriver here to
release spring, then insert wires
3. You will need to run wire from the motors to the controller. We typically use 16-2 wire. Take the cover off of the motor and
fasten the black wire on the black wire terminal and the white wire on the white wire terminal. (See Fig. 3)
Run these wires down to the controller and take the wires from the gearbox motor and insert into the bottom right grommet of
the controller. In the controller, insert these wires to the East/West terminals.(Refer to Fig 4)
Figure 3
Figure 4
Black Wire & White Wire
Terminals
These 2 wires are from
the Gearbox motor, they go to the East & West
Terminals
These 2 wires are from the
Actuator motor, they go to
the North, South terminals
Mounting Holes
4. Once the wires are all hooked into the controller, you can power up the controller to set the time/date. To do this, push the
MAIN MENU button and move the cursor to SET CLOCK/DATE. REMEMBER TO SET TIME IN STANDARD TIME.
5. You will now need to ensure your controller is set to the correct
program. Hit the NEXT button until you come to the second screen
and the cursor is next to CONT. APPLICATION(see FIG 5), then
press ENTER. You have two options, DUAL AXIS or SINGLE
AXIS, which is changed by pressing the NEXT button. When your
application is on the screen, press EXIT two times.(see FIG 6)
Figure 5
Figure 6
6. When you are on the home screen, you need to be sure that “AUTO
TRACKING IS ON” is displayed. This means that the tracker will move
according to the programming in the controller. If this is not on, then press
Main Menu, then scroll down to AUTO TRACKING and press ENTER to
turn Auto Tracking on or off. Note: If you plan on doing any type of
maintence on the tracker, it is adviced to turn off the auto tracking to
prevent personal injury or damage to the tracker.
www.dhsolar.net Page 8
The DH Solar tracker is now assembled at this point and we will now begin to work with the motors and the controller. The controller
has a 110V AC power pack, that has an output of 24V DC to operate the DC motor to travel west, to follow the sun and returning at
midnight. The controller also operates a second motor to adjust the “tracker” weekly to allow for the changing of seasons. The outputs
of the controller are two sets of wires to attach to each motor. The controller is programmable to operate to the second. Normal
operation is to move the solar panels each half hour for about 44 seconds (adjustable) and to return the unit at midnight. The return is set
to a longer operation than needed so the panels return to the east and stop with the built in limit switch within the motor. You will see the
limit switch within the motor in photo 8A on the next page. The declination adjustment is just a few seconds once a week. Maintenance of
the system is to lubricate the chain twice a year. If you have purchased our inverter rack, the rack has the 4 holes pre-
drilled to mount the controller to it.
DH SOLAR Controller Instructions Setting the Time & Date Push the MAIN MENU button, Then press the NEXT button until the cursor is next to the SET CLOCK/DATE line, then Press ENTER The first segment is the day of the week, press the “+” until you get to the correct day, then press NEXT. The following segment is the Month, press the “+” until you get to the correct Month, then press NEXT. The following segment is the year, press the “+” until you get the correct Year, then press NEXT. The following in the hour and minutes, set them accordingly, press NEXT and remember YOU MUST SET THE CLOCK TO STANDARD TIME, DO NOT SET TO DAYLIGHT SAVINGS. You can then press EXIT two times.
Manual Moving of the Tracker If you need to manually move the tracker, follow these steps: Press the MAIN MENU button, then press ENTER. You will then have the option to move EAST/WEST or FORWARD/BACK. If you want to move it East or West, simply press the button under MOVE EAST or MOVE WEST. When you are done moving the tracker, press STOP. You can then repeat the steps, move to the FORWARD/BACK moves, or EXIT the screen. Changing the Start Time/Move Time/ Duration Time If you need to adjust the move times follow these instructions: From the home screen, press the MAIN MENU button, press the NEXT once until it reaches the EDIT MOVE PARAMETERS line, then press ENTER. Then decide if you need to change the West Moves, East Move, or Solstice Move. To change ALL West moves, Press ENTER, then change the duration in which the tracker moves for each WEST move. If you want to individually change each WEST move, press ENTER when the cursor is next to the WEST(INDIVIDUAL) line. When you are in the next screen, you can choose which move you want to change by pressing the NEXT button, then press the EDIT button. You can then change the time the move starts and also the duration of the move. To change the Solstice or East moves, follow the same steps as above. Turning Off a Move If you want to turn off a move(i.e. don’t want the tracker to move at 8:00 am, so you want the first move to start at 8:30 pm, etc) Push MAIN MENU button, then EDIT MOVE PARAMETERS, WEST(INDIVIDUAL). Choose the move you don’t want and then change the Duration time to 0:00. WARNING: If you power the tracker from another source, you must disconnect the controller wires from the motor. Failure to do this will result in damaging the controller. When you are done making any changes, you MUST make sure that the AUTO TRACKING IS ON on the home menu page.
Page 9
Limit can be adjusted by repositioning the
adjustment screw shown here with blue arrow.
Loosen the set screw that is holding the pin in
place, slide the pin left/right to make changes and
retighten the set screw. West Limit/North Limit is
shown with red arrow. The adjustment screw will
set the east limit/south limit, the threaded rod(red
piece) will set the west limit.
Set screw
West Limit Switch
North Limit Switch
Page 10 www.dhsolar.net
East Limit
South Limit
Adjustment screw
Motor stops when it hits the limit switch. This picture shows
the limit stop at the West Limit Switch/North Limit Switch.
Photo 8A
9.1 You will need to set the limits in both the solar tracking motor and the solstice motor . This task should be
performed after your controller is hooked up as the controller will be needed to adjust the limit switches in the motors.
To do this you will need to open each motor and make the adjustments by loosening the set screw and adjusting the
adjustment screw.
Solstice Motor You will need to first set the solstice motor limits. The solstice motor is the motor that is attached to the
gold colored actuator. You will need to add 23 degrees to your latitude to get your most forward position. It will vary by
your location(ie. Prairie du Chien, WI is located at about 43 deg latitude. We set the panels to approximately 66 deg.)
With an angle finder, on the panels, use the controller to manually move the tracker “forward” until you reach your
desired degree. Adjust the gold colored screw so it presses into the South limit switch and stops the motor. Double check
your angle to ensure you have it set correctly.
Once this is done, manually move the solstice adjustment “back” for a few seconds and then “forward” again to ensure
the limit is set to your desired angle. Tighten the set screw when you are finished adjusting the limits.
You need the tracker to be in its most forward position before we set the east and west limits so that you do not hit the
ground at your most easterly point (start of the day) and for setting the west limit which determines your end of day
movement. Make sure your panels are facing south when you are ready to do this.
Once in the correct approximate most forward position and the limit switch has stopped the motor, you are ready to set
the West/East Limits.
You will be moving the solar tracker left and right during this next process manually with a drill and the
controller. It is recommended that you have a thumb screw large enough to be used in the drill chuck that
can be inserted into where the motor is fastened.
Setting the Limits on the Motor for Azimuth travel. WARING: If an alternate DC device is used to move the tracker motor, YOU MUST Disconnect the wires on
the Motor that are connected to the Controller. Failure to disconnect these wires will result in the Controller
circuitry to fail!
Page 11
10a. You will need to put two additional bolts through the can & horizon mount, along
with tightening the first bolt you put through. To do this, use a large “C” clamp and
tighten the top on the can next to the holes. Tighten the first bolt that was there. Insert
the second bolt, tighten the plates with the clamp, then tighten to the bolt. Finally, insert
the third bolt, tighten the plates with the clamp and tighten the bolt.
2 additional bolts to insert and tighten.
Remember to tighten the bolt already
there first, while using the clamp. Then
insert the second bolt and repeat the
steps. You must use a “C” clamp or bessy
clamp next to the holes and clamp very
tight to ensure a very tight bolt. You must
do this with all 3 bolts.
9.2 Setting the West limit: Take the azimuth motor off of the tracker. Using a drill, drive the tracker to the
most westerly position you want to stop tracking for the day. Keeping in mind to make sure you have clearance
from the bottom of the panel to the ground. Depending on your location, you may want to keep it above the
ground a little more if you receive heavy snowfall in the winter. Now you will take the azimuth motor, while it
is off of the tracker, (which is already wired to the controller) and drive the motor using the controller to the
west watching the threaded rod until it clicks the limit. Stop the controller when you hit the limit.(Note: your
azimuth motor comes set at the West Limit, if you drive the motor West and it doesn’t move, it means that it is
still set on the West limit and you can proceed as well) Now put the motor back on the tracker mount. At this
point both the tracker/panels and the limit for west are set. (You may make adjustments later if you need).
9.3 Setting the East limit: To set the east limit, use the adjustment screw. Loosen the set screw that holds the
adjustment screw in place in photo 8A. With the cover off of the azimuth motor, and having the motor wired
to the controller, drive the motor, that is attached to the tracker’s gearbox, all the way over to the east (sun
rise position) by using the controller manual move on East, keeping in mind that you need to have clearance
from the ground to the panel. Also watch to make sure the framework doesn’t hit the pole. When at the most
easterly position stop the controller and set the limit. To set the east limit, simply adjust the adjustment screw
with a screwdriver to hit the limit and tighten the set screw.
9.4 Test the limits. Using the controller, run the tracker east and then west. Make sure your controller and
tracker unit stop in the positions you just set. Please see page 10 for “MANUAL MOVE” using the controller.
“C” Clamp used along with wrenches to
tighten all 3 nuts/bolts on the can.
GROUNDING OF YOUR SOLAR TRACKER
Page 12
All grounding requirements must be done to your state’s adaptation of the National Electrical Code (NEC). Below are some pictures of grounding on one of our tracking systems. We typically use Burndy lay in lugs # BGBL-4 with a stainless steel self tapping screw.
FINAL REMINDERS -It is very important during the first couple of years to check the chain periodically to ensure that it has not stretched. You may have to tighten the chain to snug it back if there is some slack in it. Never loosen the chain unless instructed to by DH Solar personnel. -Remember to lubricate the chain at least twice a year to prevent it from rusting and also to keep it working properly. -You will want to check the nuts on all of the bolts when you lubricate the chain and tighten them if they appear loose.