Conwin has recommendations addressing common issues users may typically experience. 

Problem: Inflator is noisy when inflating balloons. There is a high-pitched sound coming from the nozzle.

Solution: An inflator become noisy when the balloon neck is being held incorrectly on the filling nozzle. The neck of the balloon should not be held with two hands, as this creates vibrations and loud noises. If the neck is not completely covering the nozzle, air/helium is slowly escaping. One hand should be used to hold the balloon neck between your thumb and index finger when inflating balloons.

Problem: Push valve sticks when inflating.

Solution: When inflating a balloon with Hi-Float, it is recommended to rotate the valve downwards so the helium does not drip into the outlet. When pumping Hi-Float into an uninflated latex balloon, make sure to pull the balloon down a bit so that the Hi-Float does not get into the neck. If Hi-Float gets into the push valve and it begins to stick, unfortunately, the outlet needs to be replaced. If Hi-Float did not get into the valve but it was exposed to moisture, spray silicone lubricant into the outlet (make sure it is not attached to the cylinder). Do not use an oil-based spray like WD-40. Push the valve up and down to allow the valve to lubricate and then attach the outlet to the tank and place a cloth over the valve. Press down to blow out the remaining lubricant. If the valve is still sticking, the outlet needs to be replaced. 

How to Position Nozzles Being Used with Hi-Float (1:30 mark)

Problem: The inflator is leaking.

Solution: If there is a hissing noise while using the inflator, the helium cylinder or inflator possibly may have a leak. Try the inflator on another cylinder. If the leak stops, the cylinder is faulty and needs to be serviced. If the leak continues, conduct a leak-check test by spraying a bottle with soapy water around the area of the inflator where the suspected leak is located. There may be a leak if large bubbles appear in one area. Clean the inflator immediately after testing to prevent water damage. If the leak has been located at the cylinder connection, close the cylinder valve. If the inflator leaks at the cylinder connection, close the cylinder valve, bleed the pressure out of the inflator, and then firmly tighten the cylinder connection. Repeat the leak-check test. The O-Ring may also need to be replaced which is really easy to do. See the link below. If the leak location still cannot be located, bring the helium cylinder and inflator back to where it was purchased to have it serviced. 

How to Replace O Ring 

Performing a Leak-Check Test (2:40 mark) This example is used on a draft beer dispense system but it is the same process.

Problem: Faulty pressure gauge.

Solution: If the pressure gauge moves up and down during inflation, this suggests that the cylinder valve is not fully open. If the pressure reading is incorrect, it cannot be fixed and has to be replaced. This could have happened by dropping it so take caution when handling the equipment.

Problem: Foil and Bubble Balloons are inflating too slow.

Solution: Foil balloons are meant to inflate slowly when using Conwin's Auto-Fill Foil Outlet in order to avoid damaging the valve. If balloons are inflating slower than usual, make sure that the nozzle and balloon are pointed downwards during inflation and make sure the balloon's valve is not folded over. If an electric inflator with an auto-fill foil outlet is being used, the nozzle cannot be re-positioned. Call the store where the unit was purchased to ask if they can service it. If it is a Bubble Balloon that is inflating slowly, check that the brass bubble button is being held and that the valve inside is not twisted or damaged.