UNDERSTANDING THE "MAGIC" THAT MAKES BIG GUN POSSIBLE
The regulator is designed to take high-pressure CO2 from a CA cylinder and deliver it to the guns at a lower, safer pressure. The regulator is comprised of a specially designed internal valve encased in a brass housing. This valve commands the flow of CO2 between high- and low-pressure (gun-pressure) CO2 chambers in the unit.
High-pressure CO2 from the cylinder passes through the regulator and is reduced to 100-140 psi above the ambient pressure (14.7 psi at sea level). Since the regulator must be maintained at any ambient pressure, the regulator is designed to adjust for decreasing tank pressure and, at the same time, compensate for changes in ambient pressure (we don't really have to be concerned with changes in ambient pressure since our ships do not fire underwater).
The regulator is engineered using a piston valve assembly that can be classified as "balanced" or "unbalanced", with Big Gun regulators falling into the classification of unbalanced piston.
PISTON REGULATORS
The piston regulator (Figure 1) operates by utilizing the opposing air pressure forces of the gun-pressure chamber and the main balance spring. These forces move a hollow piston. CO2 flows through the hole in the piston to the guns. Here's how it works:
When the guns fire, pressure inside the gun-pressure chamber drops, which allows the spring to push the piston. This movement opens the valve. High-pressure CO2 flows from the cylinder into the seat chamber and is funneled between the seat and the tip of the piston. As CO2 enters the piston orifice, its velocity increases and it expands, resulting in a decrease in pressure. The CO2 continues to flow through the piston into the gun-pressure chamber until the gun stops firing.
When the gun stops firing, pressure in the gun-pressure chamber increases until it equals the force exerted by the main balance spring and ambient pressure. When equilibrium occurs, the piston seats and the airflow from the tank ceases.
Piston regulators sense changes in ambient pressure with a specialized chamber. External water or air enters this chamber (that's what the hole in the side of your regulator is for), allowing water or air at ambient pressure to be applied directly to the piston assembly. Since the piston is exposed to water, two vital O-rings inside the regulator are required to prevent water from entering the air chamber. These O-rings are subject to malfunction if damaged by sand, salt, pond scum, or small pieces of balsa wood, so care must be taken to thoroughly rinse the regulator to remove impurities.
UNBALANCED REGULATORS
In the unbalanced regulator, the valve seat is located on the high-pressure side of the valve. During firing, the valve opens and delivers CO2 to the guns. When the valve closes, pressure in the gun-pressure chamber returns to a preset level.
Tank pressure effects the valves' operation. High pressure CO2 from the tank is used to force this valve open. As a result, the valve orifice must be small to prevent too much air from flowing into the gun-pressure chamber. But as the tank pressure drops, less CO2 will be forced through the small valve opening, resulting in slower filling of the guns accumulator tank.
SPRINGS
Regulators are available with either a 100, 125 or 140 pound interchangeable spring. If you wish to change the spring, shut off the tank, de-pressurize the regulator and unscrew the upper half of the regulator. The spring may then be changed and the cap replaced. Springs come in three ratings: 140 psi springs are red, 125 psi springs are silver, 100 psi springs are lavender.
MAINTENANCE
Your 1/4 inch ball bearings are bouncing off of the enemy's hull. Or worse yet, one of your accumulator tanks has just ruptured. One possible source of your problem may be your main regulator putting out the incorrect air pressure. First check the output pressure of your regulator with a pressure gage. If your regulator is putting out too little air pressure, your O-rings need to be checked. Too much pressure is most likely caused by dirt inside the cap housing and a lack of lubrication.
Luckily, the unbalanced piston regulator designs are easy to service with few moving parts. Most likely your regulator just needs a good cleaning. To clean your regulator, just unscrew the cap and remove all of the components as seen in FIGURE 2. When disassembling your regulator for cleaning, first clean all the parts with a clean rag. If the parts can be run under water, use plain hot water (hot soapy water is optional but not needed). Dry parts thoroughly after rinsing.
Inspect the two O-Rings found on the piston. A cracked or torn O-Ring will need to be replaced or a loss of air pressure will occur. Apply a small amount of lubricant (Lightly lubricate O-Rings with DOW III lubricant, or equivalent.) to the parts, one at a time. When lubricating parts, it is best to put the regulator together as you go, so the parts don't get dirty from lying on the rags.
LUBRICANTS