Power Curbers - Technical Supoprt Frequently Asked Questions

Frequently Asked Questions...

1. What are the advantages of slipforming curb over hand forming?

Slipformed curb is stronger: Low-slump concrete is stronger than the high-slump concrete used in hand pouring.

Slipformed curb is faster: You get more production with the same number or fewer people, resulting in lower price to the end user.

Traffic patterns are diverted for a shorter time due to the speed of completing the project; thus, the traveling public (the taxpayer) is happier.

Low-slump, air-entrained concrete is more resistant to salt and slag deterioration.

2. Why does my front crawler search back and forth when I'm pouring?

Several things may cause this. Here are a few simple procedures to help determine where the problem is originating. Do the following one at a time to determine the problem.

Do this:	To determine if the problem is this:
Swap your steering sensor with a sensor you know is good.	Defective Sensor
Swap the steering sensor curly cord with a cord you know is good.	Defective Curly Cord
Swap the steering amplifier with an amplifier you know is good.	Defective Amplifier
Swap the servovalve with one you know is good (steering servovalves on late model 5700s, 8700s, and 5700-Bs are different from the grade and slope servovalves).	Defective Servovalve
Check the feedback pot for proper operation and correct timing.	Defective or Improperly Timed Feedback Pot.

3. What is the recommended maintenance schedule?

Check and Clean Schedule			Interval
Ref. No.	Identification	Type of Service	Daily (10 Hrs.)	Weekly (5 Hrs.)	Monthly (250 Hrs.)
1	Engine Oil Level Check	Check	X	-	-
2	Engine Oil Level Check	Check	X	-	-
3	Engine Heat Exchanger Cooling Fins (Radiator) Clean	Clean	-	-	X
4	Engine Air Filter Check	Check	X	-	-
-	Engine Air Filter	Clean	-	X	-
5	Hydraulic Oil Level Check	Check	X	-	-
6	Hydraulic Oil Cooler Fins Check	Check	X	-	-
7	Fuel Level Check	Check	X	-	-
8	Conveyor Clean	Clean	X	-	-
9	Conveyor Drive Chain Tension Check	Check	-	-	X
10	Crawler Chain Tension Check	Check	-	X	-
11	Crawler Chain Tension Check	Check	-	-	X
12	Crawler Idler & Roller Bearings Check	Check	-	-	X
13	Trimmer Torque Hub Oil Level Check	Check	-	-	X
14	Pump Drive Oil Level Check	Check	-	-	X
15	Mold & Hopper Clean	Clean	X	-	-
16	Sensor Hubs & Wands Clean	Clean	X	-	-

Change Schedule			Interval
Ref. No.	Identification	Type of Service	50 Hrs.	250 Hrs.	500 Hrs.	2000 Hrs.
1	Servo System Hydraulic Filter Element	Change	1st Time	X	-	-
2	Hydraulic Tank Return Filter Element	Change	1st Time	X	-	-
3	Hydraulic Tank Breather Filter Element	Change	-	X	-	-
4	Engine Oil	Change	1st Time	X	-	-
5	Engine Oil Filter	Change	1st Time	X	-	-
6	Engine Coolant	Change	-	-	-	or 2 years
7	Air-Cleaner Element	Change	-	X	-	-
8	Fuel Filters	Change	-	-	X	-
9	Hydraulic Oil	Change	-	-	-	X
10	Hydraulic Tank Suction Screen Filters	Clean	-	-	-	X
11	Crawler Torque Hub Oil	Change	-	-	-	X
12	Trimmer Torque Oil	Change	-	-	-	X
13	Pump Drive Oil	Change	-	-	-	X

4. What are some of the Brand Name Equivalents for the hydraulic oil?

Hydraulic Oil Brand Name Equivalents

AMERICAN	Industrial Oil 46
CITGO	Pacemaker 46
EXXON	Nuto H46 & Terrestric 46
MOBIL	DTE 25
PHILLIPS	Mangus 46
SHELL	Tellus 46
SUN	Sunvis 46
TEXACO	Rando 46
UNION	Unax 46

5. Why does the post leak down when the engine isn't running?

There are 2 possible reasons for this occurrence:
Probable Cause:	Action:
Defective counter balance valve	Exchange the counter balance valve on the trouble post with a known good, pre-set valve. • If the post stops leaking down, replace the defective counter balance valve. • If the post contnues to leak, continue troubleshooting.
Excessively worn post cylinder	Visually check for hydraulic oil leakage at the rod end of the cylinder (oil will seep around the lower cylinder mount bolts on the underside of the inner post yoke, if there is external leakage). • If excessive external leakage is present, repair or replace hydraulic cylinder. • If no excessive leakage is present, the problem could be internal leakage. Remove the cylinder and disassemble, inspecting the cylinder bore and piston o-rings.

6. Why does my Change Filter light come on but then go off when my machine warms up?

Probable Cause	Action
Cold Hydraulic Oil	Warm up the machine to operating temperature before using.

7. Why does my post or front crawler drift when the amplifier is in Standby?

Probable Cause:	Action:
Servovalve NULL position	Adjust the NULL position on the servovalve (as discussed in Section 4, Page 4-15 of the 5700-B Maintenance Manual Revision 12-15-96) until the drifting stops. If drifting cannot be adjusted, replace or rebuild the defective servovalve.

8. What mix design or slump do you recommend?

Contents	Cubic Yard	Cubic Meter
Sand	1500#	891 kg
Cement	540#	321 kg
Coarse Aggregate	1600# (1/2" - 13mm)	951 kg
Water	39 gallons (320#)	193 liters
Air	4% - 6%	4% - 6%
1-1/2" - 2" Slump 3000 psi

For a typical barrier/parapet:
Contents	Cubic Yard	Cubic Meter
Sand	1400#	321 kg
Cement	700#	891 kg
Coarse Aggregate	1700# (1/2" - 19mm to 25mm)	1011 kg
Water	32 gallons (320#)	158 liters
Air	4% - 6%	4% - 6%
1" Slump 4000 psi

9. How do I order molds?

Fax Power Curbers or your dealer a sketch of the mold you want, including all dimensions. See Molds Page.

When you receive the "A" Size (8 ?" x 11") Print, look it over for mistakes, make the changes desired and fax the signed approval or changed "A" Size print back to Power Curbers or your dealer along with the completed approval form.

When the final signed print is received we will begin work on the mold.

Lead times vary from mold to mold. Please call or e-mail us for mold availability.

10. If I am hand forming, what is the break-even point on purchasing a curb machine?

If you can pour as much as 20,000 to 25,000 linear feet (6,100 to 7,625 m) of curb per year, you can justify the cost of a 5700-B, financing it over a 3- to 5-year period. To pay for the machine, you build $1 a foot into the curb cost. The machine will increase your production, cut your labor and allow you to bid more competitively.

11. Can I bypass the emergency stop?

Never bypass or disconnect the machine's Emergency Stop Circuit in ANY manner which will render it inoperative.

12. Troubleshooting the High Pressure Water Pump

Problem	Cause	Remedy
Pulsation	Valve stuck open.	Check all valves, remove foreign matter.
Low pressure	Worn nozzle.	Replace nozzle, use proper size.
	Air leak in inlet plumbing.	Disassemble, reseal and reassemble.
	Relief valve stuck, partially plugged or improperly valve seat worn.	Clean, adjust relief valve; check for worn and dirty valve seats. Kit available.
	Inlet suction strainer clogged or improperly sized.	Clean; use adequate size. Check more frequently.
	Worn packing. Abrasives in pumped fluid or severe cavitation. Inadequate water.	Install proper filter. Suction at inlet manifold must be limited to lifting less than 20 feet of water or -8.5 PSI vacuum.
	Fouled or dirty inlet or discharge valve.	Clean inlet and discharge valve assemblies.
	Worn inlet, discharge valve blocked or dirty.	Replace worn valves, valve seats and/or discharge hose.
	Leaky discharge hose.
Pump runs extremely rough, pressure very low	Inlet restrictions and/or air leaks. Stuck inlet or discharge valve.	Replace worn cup(s), clean out foreign material, replace worn valves.
	Restricted inlet or air entering the inlet plumbing.	Proper size inlet plumbing, check for air tight seal.
Water leakage from under manifold. Slight leakage	Worn packing.	Install new packing.
	Cracked plunger.	Replace plunger(s)
Oil leak between crankcase and pumping section.	Worn crankcase piston rod seals. O-Rings plunger retainer worn.	Replace crankcase piston rod seals. Replace O-Rings
Oil leaking in the area of the crankshaft	Worn crankshaft seal or improperly install oil seal O-Ring.	Remove oil seal retainer and replace damaged O-Ring and/or seals.
	Bad bearing.	Replace bearing and any spacer or cover damaged or cover damaged by heat.
Water in the crankcase	May be caused by humid air condensing into water inside the crankcase.	Change oil intervals. Use SAE 30 non-detergent oil.
	Worn packing and/or piston rod sleeve, O-Rings on plunger retainer worn.	Replace packing. Replace O-Rings.
	Cracked plunger.	Replace plunger(s)
Oil leaking from underside of crankcase	Worn crankcase piston rod seals.	Replace seals
	Scored piston rod.	Replace piston rod.
Oil leaking at the rear portion of the crankcase	Damaged crankcase, rear cover O-Ring, drain plug O-Ring, or sight glass O-Ring.	Replace cover O-Ring, drain plug O-Ring, or sight glass O-Ring.
Loud knocking noise in the pump.	Pulley loose on the crankshaft.	Check key and tighten setscrew.
	Broken or worn bearing or rod(s).	Replace bearing or rod(s).
	Valve stuck open or shut, or not opening enough.	Replace bad valve.
Frequent or premature failure of packing.	Scored, damaged or worn plunger.	Replace plungers.
	Over-Pressure to inlet manifold.	Reduce inlet pressure.
	Abrasive material in the fluid being pumped.	Install proper filtration on pump inlet plumbing.
	Excessive pressure and/or temperature of fluid being pumped.	Check pressures and fluid inlet temperature, be sure they are within specified range.
	Over-pressure of pump.	Reduce pressure.
	Running the pump dry.	Do not run the pump without water.
	Upstream chemical injection.	Use downstream chemical injection.

13. What can I expect in the way of profit, per day, with a curb machine?

Realizing that costs may vary, depending on your location, here is an estimate on 24-inch wide (61cm) curb and gutter, for your comparison:

Concrete:
$120/yd divided by 20 ft. yield per yd = $6 per linear foot

Labor:
5 men x$30/hr x 8 hours = $1,200
$1,200 divided by 2,000 linear feet per day = $.60/foot

Total Cost:
Direct cost (concrete + labor) = $6.60/foot
Overhead (estimate) = $1.65/linear foot
Total cost (estimate) = $8.25/linear foot

Daily Profit:
Bid price = $12/foot = $24,000
Less cost: $8.25 x 2,000 = $16,500
Daily profit (estimate) = $7,500