 of cold winter weather means a slowdown for many highway maintenance projects. Winter is the time for equipment maintenance and repair in preparation for the busy warmer months ahead, but not for the crack sealer. Just around the time the first frost hits the crack sealing crew is called into action. Crack sealing is a cold weather operation for two reasons. First the colder temperatures contract the pavement so cracks in the surface are at their widest. Second winter weather provides the ideal temperatures for the sealant to set up and cure quickly. Crack sealing extends the life of our roads. If left untreated these cracks would allow water to seep under the pavement where it could eventually do serious damage to the road. Because crack sealing is vital to maintaining our roads and because the crack sealing season is relatively short it's important that you learn how to maintain and use the crack sealer properly and safely. Here in part one of crack sealer operation we'll take a general look at the unit. We'll cover the major components first and then we'll look at the unit's valves and controls where they are and what they do. Part two will cover operation from lighting the burners in the morning to cleaning out the unit at the end of the day. Most of the information presented in the two programs can be found in the operator's manual. Take some time to read it and keep it handy until you become familiar with the machine. The crack sealer is a complex machine and it can be dangerous if it's not operated correctly. Okay let's take a look at the crack sealer, its major components and what they do. The largest component on the crack sealer is the sealant tank. It holds 200 to 250 gallons of sealant. The sealant comes in blocks of asphalt and rubber and is loaded through a hatch on the top of the tank. Inside the sealant tank is a horseshoe shaped interior tank that holds about 80 gallons of a special type of oil called heat transfer oil. Beneath the sealant tank are two propane gas burners. The burners are fueled by the propane cylinders mounted on the rear of the unit. These burners heat the heat transfer oil which in turn heats and melts the sealant in the sealant tank. An auger inside the sealant tank agitates the sealant. The rotation of the auger sort of stirs the sealant. The constant movement helps keep the asphalt and rubber from separating during the melting process. A hydraulic pump moves the liquid sealant through the system. The pump sends the sealant out through the applicator wand so it can be applied directly into the cracks. The pump can also be reversed to suck the sealant out of the lines and back into the tank. Both the pump and auger are powered by a gasoline engine. You can increase or decrease power to the pump and auger by adjusting the engine throttle. Finally there's the solvent and hydraulic oil storage tank. The tank is split in half solvent on one side and hydraulic oil on the other. The solvent usually number two diesel fuel is used to clean the lines after you use the crack sealer and the hydraulic oil is used to operate the pump and auger. Okay that takes care of the major components. Now let's look at the valves on a crack sealer. There are a lot of them. The recirculation valve on the front of the sealant tank allows you to adjust the flow of the sealant through the system. The tank valve at the bottom of the tank allows the sealant to move from the sealant tank to the pump. When both the recirculation valve and the tank valve are open the sealant recirculates through the pump up this two inch line and back into the tank. This constant movement helps heat the sealant evenly and prevents it from stiffening. When you're ready to start sealing cracks you open the applicator valve. It's right next to the recirculation valve. The applicator valve sends the sealant through the lines and to the applicator wand. The applicator wand has a valve too. Open the valve to apply the sealant and close the valve to stop the flow. To flush solvent through the system you open the clean out valve. The clean out valve allows solvent to enter the lines so it can be pumped through the system to clean out the lines. Finally there's the drain valve. It's at the bottom of the front of the sealant tank and you use it to drain the solvent from the system after clean out. Okay that's it for the valves. We'll take a closer look at them in part two. Now for the controls. The two controls you use most often are for the hydraulic pump and auger. The control on the right controls the rotation of the auger. You can rotate the auger clockwise or counterclockwise by moving the control up or down from the center neutral position. The control on the left operates the hydraulic pump. Push it down to pump material through the system and push it up to reverse the pump for suction. The burner control box at the rear of the unit has three controls. The two levers on the outside of the box are the burner controls. They have to be opened to light the burners. Inside the control box is the temperature control dial. You use the dial to set the temperature of the heat transfer oil. There are three temperature gauges on the crack sealer. One tells you the temperature of the heat transfer oil. One gives the temperature of the material in the sealant tank and the third one tells you the temperature of the sealant circulating through the two inch line. The gauge on the top of the sealant tank tells you how hot the material is inside the tank and the gauge on the two inch line reads the temperature of the sealant as it circulates through the system. These two gauges have to register the same temperature before you begin applying the sealant. By now you've probably gotten the idea. The crack sealer is not a simple machine. The purposes of all these controls will become a little clearer when we take a more detailed look at operating the unit in part two. In part one of this program on the crack sealer we covered the unit's major components and its valves and controls. Now in part two we'll look at operation. First we'll cover daily checks then lighting the burners, agitating the sealant, applying the sealant and finally cleaning out the unit at the end of the day. Okay let's get started with daily checks. Most of the checks you make can be done after you light the burners and start heating the sealant. That's because it takes a while up to an hour to heat the sealant enough to begin agitation. But there are four things you should check before you light the burners. First make sure you've got some sealant in the sealant tank. Never heat a dry tank. Next check the level of the heat transfer oil. The depth stick is on top of the sealant tank. Keep it near the full mark on the stick. If it's low be sure to add the right type of oil. It has to withstand temperatures in excess of 500 degrees and don't overfill the tank. The oil needs room to expand as it warms up. Then check the solvent and hydraulic oil levels. Remember they share this split tank solvent on one side and oil on the other. Both levels should be about three to five inches from the top of the tank. Okay at this point you're ready to light the burners but we'll cover that a little later. For now let's stick with the daily checks. After you light the burners take some time to look over the unit. Check the trailer tires for correct inflation, uneven tread wear or loose and broken lug nuts. Check the engine oil every day. Keep it near the full mark on the depth stick and note the condition of the oil. Extremely dirty or contaminated oil can ruin the engine so take a good look. Cold weather can really put a strain on the battery. Keeping it clean and maintaining the correct battery water level will help ensure easy starting on the coldest mornings. Next you should estimate how much propane you have in the cylinders. Here's an easy way to tell. When the cylinder is open frost forms at the level of the propane. This tank is almost empty and should be refilled or replaced. During your inspections you may notice a leak from the auger packing. A little leaking here several drops per minute is okay and necessary for lubrication. But if the leaking becomes excessive you'll have to tighten or repack the packing gland. Inspect the hitch and safety chains and hook up the electrical connector from the trailer to the truck. Then check the trailer's lights. If none work recheck the electrical connector and if only some work check for burned out bulbs. Finally make sure you have an approved fire extinguisher on board. Keep it fully charged and accessible. You'll work with flammable materials all day and you may not have time to look for an extinguisher if you need one in a hurry. Of course your daily checks shouldn't end when you leave the yard. In fact they should continue throughout the day. Basically you just have to be alert. Anytime you work with heat and flammable materials under pressure there's always a danger of someone getting hurt. Inspect the unit occasionally throughout the day. Pay attention to how well it's running and be prepared to correct or report operational problems. But we're getting a little ahead of ourselves so let's back up a bit and look at lighting the burners. Rule one never light the burners indoors. You need plenty of ventilation to light the burners safely. So if the crack sealer has been stored in the garage unplug the electric heating elements that kept the sealant warm overnight and move the unit outdoors. When you get it outside open the valve on one of the propane cylinders and set the pressure regulator to 18 psi. That sends propane gas from the cylinder to the burner pilots and the hand torch. Take the hand torch out of its bracket open the valve and light it. Then press down the two pilot buttons in the burner control box with one hand and hold the torch near the burner pilots with the other hand until you see the pilot's light. Release the pilot control buttons after about 30 seconds. Shut off the hand torch and open the two burner valves on the outside of the control box. The pilots should light the burners in about 30 seconds. Check the temperature control dial. It regulates the temperature of the heat transfer oil. Set it about 75 degrees higher than the recommended application temperature of the sealant you're using. For example the sealant we use most often has an application temperature of 350 degrees. So the temperature of the heat transfer oil should be set 75 degrees higher or at about 425 degrees but never set the oil temperature higher than 500 degrees. That's too close to the oil's flash point. It could cause a fire or an explosion. Okay let's review the procedure so far. First open the propane cylinder valve. Set the pressure at 18 psi. Press the pilot control buttons down and light the pilots with the torch. After 30 seconds release the pilot buttons. Turn off the hand torch. Open the burner valves and check the temperature setting for the heat transfer oil. Now on some of our newer crack sealers the procedure is a little different. The burners are completely automated. There are instructions for lighting the burners printed on the control box. Here's the procedure. To light the pilots you just have to open the burner valves and open the propane valve. Then open this line ball valve. The pilots will light in 5 to 10 seconds automatically. When the pilot's light set the temperature control dial at the recommended temperature. The burners will kick in in just a few seconds. Rule two never leave the unit unattended while the burners are on. So if you have to leave the crack sealer for any reason close the propane valve and when the burners flame out close the burner valves. Only then is it safe to leave the unit. Okay now let's take a look at agitation. Normally you can begin agitation within an hour after lighting the burners. Agitation accomplishes two things. First agitating the sealant speeds up the melting process. And second agitation helps keep the asphalt and rubber in the sealant from separating as it's heated. To begin agitation you have to start the crack sealer's engine. The engine powers the unit's hydraulic auger and pump. After you start the engine move the auger control up or down from the center neutral position. The auger rotates inside the sealant tank and stirs the sealant. Remember you can reverse the auger if it jams by moving the control in the opposite direction. Continue agitating the sealant until it is liquid throughout. You can add sealant blocks during this period but always stop the auger before you lift the tank lid. That lessens the chance of splashing yourself with hot sealant when you drop in a new block. And don't add too many blocks at once. That'll slow down the melting process. Two blocks every five minutes is about right. After you load the machine shut off the burners. Rule three never travel to or from the job site with the burners on. Now let's cover application getting the sealant out of the tank and into the cracks. When you get to the work area relight the burners and continue agitating the sealant. It'll take a few minutes to bring the sealant up to application temperature after the trip from the yard. But before you can begin applying the sealant the surface has to be prepared. All cracks should be blown clean and dry with compressed air to remove dust and moisture from the surface. The next step is to begin pumping the sealant through the system. Move the pump control lever down for pumping and open the recirculation valve. Next open the tank valve to let the sealant recirculate through the pump up the two inch line and back into the tank. Check the temperature gauge on the two inch line. It should match the temperature of the material in the sealant tank. Then place the applicator wand in the opening at the rear of the tank and open the wand valve. Now to get the sealant pumping through the wand open the applicator valve. When the applicator valve is open it diverts the sealant flowing through the two inch line and sends it to the applicator wand. You can control the flow of the sealant now by adjusting the recirculation valve. The tighter you close it the more sealant will move through the wand. Okay let's review. To pump sealant through the system move the pump control down open the recirculation valve then open the tank valve to allow the sealant to enter the pump and circulate through the two inch line. When the sealant in the two inch line reaches application temperature open the wand valve and place it in the rear tank opening. Then open the applicator valve to send the sealant to the wand and adjust the recirculation valve until you get the pressure you need. Now you're ready to start sealing cracks. Turn off the wand valve and remove the wand from the tank. Then open the wand valve and place it down low near the crack. That'll help you put the sealant right where you want it and prevent splashing the hot sealant on yourself or others. As you apply the sealant to the cracked surface another operator spreads it so the sealant covers the crack completely. The spreading should follow the application immediately so the sealant won't harden before it's spread and remember you can control the amount of sealant coming out of the wand by adjusting the recirculation valve until you get the flow you need. One important point here if you stop work for any reason place the wand in the rear tank opening with the wand valve open that will keep the sealant flowing through the wand until you're ready to begin work again. You probably have to add sealant to the tank during the day and when you do follow these precautions. Always stop the auger before you open the tank lid and if you don't have the loading ramp on your unit lower the block into the hatch carefully. Try to keep your face away from the tank and close the lid as much as possible before you drop the block into the tank. Try to keep the level of the melted material about a foot above the auger or just about at the level of the handrail on the side of the tank and remember the liquid sealant is hot and certain exposed parts of the machine can reach temperatures of some 500 degrees. Be alert and be careful. Wear protective clothing. Inspect the unit now and then throughout the day. Don't operate unsafe equipment. Now we'll cover cleaning out the unit at the end of the day. Clean out involves getting the sealant out of the pump and lines then flushing out the system with solvent. Because clean out is a complicated and crucial procedure I'll run through it once and then review. First close the propane valve and shut off the burners then reverse the pump to suck the sealant out of the lines and back into the tank. Next close the tank valve to shut the sealant out of the system. Now you've got to flush solvent through the pump and out of the wand. So close the recirculation valve all the way so the solvent won't be forced into the sealant tank. Move the pump control lever down for pumping and open the clean out valve to pump solvent through the lines. Hold the wand over a bucket with the wand valve open. When the solvent flows freely through the wand close the clean out valve and put the pump control lever back in neutral. Okay you flushed the sealant out of the system now you have to get the solvent out too. Place the bucket under the drain pipe and open the drain valve. Move the pump control up for suction. The pump will suck the solvent out of the system and into the bucket. When all of the solvent has been pumped out close the drain valve and shut off the engine and that's it. Sound complicated? Well it is. There are a lot of steps involved. Let's go over clean out one more time. First shut off the burners then reverse the pump to suck the sealant out of the wand. Keep the wand valve open. After a minute or so close the tank valve to shut the sealant out of the system. Close the recirculation valve so solvent can't get into the sealant tank. Move the pump control down for pumping and open the clean out valve. When the solvent flows freely through the wand close the clean out valve and stop the pump. Now to get the solvent out of the system open the drain valve and reverse the pump until all the solvent drains from the system. Then stop the pump close the drain valve and shut off the engine. Don't worry if you're a little confused you'll get a chance to practice later on. Just remember you have to do three things. First get the sealant out of the lines. Second flush solvent through the system and third drain the solvent from the system. After you shut down coil up the hose in the rear chamber and place the wand in its holder and when you get back to the yard plug in the electric heating elements to keep the remaining sealant in the tank warm overnight. Okay that's it for our programs on the crack sealer. As you've seen the crack sealer is a complex piece of equipment and the crack sealer operator has a lot to do. It's going to take some time and some practice to learn how to do it right.