After a winter of non-flying storage, your balloon system may be in need of some cleanup. Many pilots have stored the system after the last flight, not realizing they were putting it away for the winter. Several things can happen during this period of storage.
You should perform some unhurried checks before you go out to a launch site and find a problem that either keeps you on the ground on a beautiful flying day, or ruins your whole weekend.
Check your battery operated equipment, especially instruments and radios, and replace any weak batteries. This is also a good time to change smoke detector and propane detector batteries in your trailer and balloon storage area. Charge any rechargeable batteries, as in aircraft radios and aircraft night lights.
Small insects and spiders may have taken up residence in your fuel system. When weather permits, take the system outside, and remove the fuel cylinders and the burner. Inspect the fuel cylinders for dents or damage. Check any valve openings and relief valve openings for spider and insect nests. Remove them if you find any.
Check the pilot light tubes on the burners. Remove any insects or nests you find anywhere in the burner. If any hoses or fittings were stored uncovered, blow out any obstructions with compressed air. If you do not have a compressed air source, move the system to an open area with no ignition source and briefly clear the lines with a quick blast of propane. If you do not have enough caps and plugs to cover all your lines and fittings, obtain them and start using them. Contact your repair station for a source of fitting covers. You can buy plugs and caps for storage use from hardware or plumbing supply stores, or propane dealers. NOTE: Fittings for in-flight use must be supplied by a source approved by the balloon manufacturer, and must not be substituted.
Reassemble your system. Install the burner and fuel cylinders. Connect the fuel lines, and turn on the propane to apply pressure. Sniff for any leaks. Spray Windex on the fuel fittings and look for bubbles. Tighten any leaking joints, being careful not to over tighten the connections. If they continue to leak, bleed the lines and disconnect the fittings. Carefully clean the mating surfaces and check them for cracks or dents. If you cannot stop the leaks, take the system to your repair station for replacement of the damaged parts.
If you have no leaks, light the pilot lights. Check that the flames look and sound normal. Try to blow out the flames. If you can blow them out, they are not working properly. Take the burner to a repair station for cleaning or repair. Fire the main burner. See that it sounds normal, and shuts off cleanly with very little afterburn. Some afterburn is normal, caused by fuel remaining in the coils when the blast valve closes. Additional burning is a sign of a sticking blast valve plunger, or a weak spring. Spray some Windex around the blast valve stem and check for bubbles. If you see any, have the O ring replaced.
After you correct any problems, you can prevent them in the future. While inspecting balloon systems, we have opened a lot of fuel cylinders. We continue to open them at annual inspections because more often than not we find foreign material inside them. We almost always find some dirt in the bottom of the cylinders. We swab this out using a rag on a stick. We often find insect bodies or parts, especially dead flies inside the cylinders. The odorant in the fuel attracts the flies, and they crawl into the propane dealer's fuel fitting. The fuel then blows them into the fuel system. They usually stay in the bottom of the cylinder, but they sometimes get back into the fuel lines and burner.
Metal shavings are another common source of fuel system contamination. They most often come from improperly assembled new fuel cylinders, and refueling manifolds assembled at balloon rallies. The new fuel cylinders are cleaned out at the first annual inspection, but I would recommend that they be inspected before the system is first flown by the new owner. The manifolds at rallies are assembled on site, and are not always completely cleaned out. We had two balloons return from a rally with metal shavings in the cylinders. One suffered from a damaged blast valve plunger that would not allow the burner to shut off. The pilot flew it to a safe precautionary landing using a cylinder valve. The second balloon returned with a damaged pilot light pressure regulator. Its pilot had a lot of practice lighting the burner with a striker until he found a landing spot.
Both of these problems were preventable. The engineering department at The Balloon Works has recommended a fuel filter that can be added to the refueling adapter for any brand. This is NOT to be inserted into any part of the in-flight fuel system, as it is not approved for in-flight use in any balloon system. It does slightly restrict the fuel flow rate, but a slightly longer refueling time is a minor tradeoff for keeping junk out of your fuel system. This filter has 1/4 inch male pipe thread connections on both ends. Other fittings may be needed to insert this fitting into your refueling adapter. A 1/4 inch female coupling may be needed unless you are replacing a short section of 1/4 inch pipe with the filter. The filter is designed for fuel flow in one direction, marked with an arrow, so carefully follow the instructions supplied with the filter. The filter will trap particles larger than 440 microns in diameter. A torque wrench is required for proper assembly.
The following parts are required:
1 Nupro B-4TF2-LE Filter Assembly, Brass, 1/4 In. Male Pipe Thread
1 Nupro SS-4F-K4-440 Filter Element, 440 Micron Stainless Steel
The total cost is approximately $50.
The parts are available from Charlotte Valve and Fitting Co., 7433 North Tryon Street, Charlotte, NC 28262-9912. Telephone (704) 598-7040, FAX (704) 596-6620. VISA and MasterCard are accepted. Your local Swagelok distributor can also supply these parts.
You, your local repair station, or your propane dealer can install this filter in your refueling adapter. Be sure to leak check the assembly before using it.