Ball Valve Maintenance and Troubleshooting

The maintenance steps for Batu Valve ball valves are compiled from the API ball valve installation, operation and maintenance manual.

Maintenance is not carried out without the valve drawing and instructions. The steps below show the general sequence; the instructions for the specific product take precedence.

Maintenance intervals

Routine inspection: At least every two years from delivery

Underground valves: Preventive maintenance and inspection once a year

After service: Next maintenance date not more than 12 months ahead

Corrective maintenance: Not scheduled; carried out on failure

Items to check on site

Paint integrity
Dust deposits
Rust and external corrosion
Condition of vent and drain fittings
Lubrication of threads and bearings
Internal and external leakage

Inspection and maintenance intervals

Condition	Interval
Routine maintenance inspection	At least every two years from the date of delivery
Underground valves	Routine maintenance cannot be carried out; preventive maintenance and inspection once a year
After service or maintenance	The next maintenance date entered on the tag does not exceed 12 months
Corrective maintenance	Not scheduled; it is the intervention carried out when the valve fails to operate

The stem is lubricated periodically according to ambient conditions. Natural gas ball valves have no fixed periodic maintenance interval; if stem sealing decreases after long service, the stem nut is tightened slightly.

Before maintenance

The valve is depressurised.
The temperature is checked at the vent and drain.
Electrical connections are isolated.
The valve is cleaned.

In preparation, site safety (flammable, pressurised or toxic environment), torque equipment, lubricant and cleaner, and the gearbox and actuator manuals where applicable, are made ready.

Body gasket replacement

The line is isolated.
The body and closure flange are marked on the right and left so that they can be reassembled in the same position.
The studs are removed and the old gasket is discarded.
The contact surface is inspected and cleaned (surface roughness Ra 1.6 – 3.2).
The new gasket is fitted without the use of sealing compound.
The closure is assembled with the ball open and tightened in accordance with the torque table.

Dismantling, reassembly and final adjustment

Parts are marked and numbered so that their orientation is clear.
Any corrosion or deformation is photographed and recorded.
Parts are cleaned without damage; a part to be replaced is compared with its spare.
After reassembly the open-close direction markings are checked.
The opening and closing torque is measured and recorded.
A full open-close cycle and a leak check are carried out.

Emergency sealant injection

Split body API valves have injection fittings on both sides of the body. If the seat or ball surface is damaged and the valve leaks, cleaner is injected first, followed by a sealant compatible with the medium. The operation is carried out slowly, with the valve fully closed and from the high pressure side.

This is a temporary measure; the permanent solution is repair of the valve.

Vent and drain

With the valve closed, the body cavity is under pressure. The vent or drain plug is not removed until the pressure has been fully released. The medium may be toxic, corrosive or flammable; protective equipment is used and the operation is carried out by experienced personnel.

Safety and spare parts

Safety rules

The body bolts of a valve under pressure are not touched. Trapped pressure may remain in the body of a closed valve, between the ball and the seats.
Before dismantling, the line is isolated, the pressure is released, and lock-out and tag-out are applied.
On a hot line, work waits until the body has cooled.
With toxic or flammable media, discharge is made to a closed system.
On an actuated valve, the power supply is isolated.

Spare parts holding

Recommended spare parts: body flange gasket, stem packing set, seat rings and body stud and nut set. Parts are ordered by valve serial number, size and pressure rating. Seats and packing that have been removed are not reused.

Troubleshooting

Symptom	Possible cause	Action
Line passes with the valve closed	Valve left partly open; PTFE seats damaged	Operate fully open or fully closed; service for seat replacement
Line passes with the valve closed	Solid particle trapped between seat and ball; surface scored	Strainer on the line; sealant injection as a temporary measure; repair as the permanent solution
Leakage at the body-closure joint	Gasket damage; contact surface dirty or damaged; closure not reassembled in its original position	Gasket replacement: dismantling with marking, surface cleaning, torque table
Leakage at the flange connection	Misalignment; bolts not tightened crosswise; old or deformed gasket	Alignment, crosswise tightening to torque, new gasket
Valve stiff to operate, high torque	Aged lubricant and foreign matter in the sealing area	Cleaner and lubrication; stem lubrication
Lever passes the stop pin, or pin damaged	Lever forced after resting against the pin	Check of pin and lever
Erosion inside the valve	Medium with solid particles, high velocity	Strainer; review of material and type selection
Stem sealing decreasing (natural gas, steel)	Tightness in the stuffing box decreases over time	The stem nut is tightened slightly
No seal can be achieved	Ball and O-ring damage	The valve is removed from the line
Rust after long storage	Unpainted surfaces not oiled in storage exceeding six months	Corrosion-inhibiting oil; indoor, dry storage

Removal from the line and disposal

The valve is removed from the line and cleaned with high pressure steam before being dismantled. Metal parts are recycled; plastic and elastomer parts are disposed of in accordance with the regulations.

Frequently asked questions

How often does a ball valve require maintenance?Why does a ball valve pass when closed?What is done when a ball valve is stiff to operate?Is sealant injection a permanent solution?

A routine maintenance inspection is carried out at least every two years from the date of delivery. Underground valves require preventive maintenance and inspection once a year. After maintenance, the next maintenance date entered on the tag does not exceed 12 months.

Damage to the PTFE seats caused by leaving the valve partly open, and a solid particle in the line becoming trapped between the seat and the ball and scoring the surface.

Aged lubricant and foreign matter may have accumulated in the sealing area; cleaner and lubrication are applied and the stem is lubricated. The lever is not forced by extending it with a pipe.

No. Injection stops the leak temporarily; the permanent solution is repair of the valve.