FAQs Archive - Page 2 of 2 - HVA

Q: Q: What happens to the gate when air pressure is lost?

A: If the valve is in the open position then it depends on the orientation of the valve. If the valve is horizontal or vertical actuator down then the gate will remain open. If the valve is vertical actuator up then the gate will pull down. If the valve is in the closed position it depends on the size of valve and whether or not a HVA solenoid was installed. If the valve was purchased without a solenoid then it is adjusted to lock-over-center which means that the internal linkage mechanism will keep it closed. If the valve was purchased with a HVA solenoid and is 6″ ID and smaller than it is also adjusted to lock-over-center. If the valve is 8″ ID and larger there is a brass check valve in the solenoid that will maintain pressure to keep it closed only if there are no leaks in the air line and air fittings.

Q: Q: What happens to the gate when power is lost?

A: If the valve was provided with a solenoid from HVA then it is adjusted to close. If the valve was not provided with the solenoid then it depends on the system and the way it was plumbed by the OEM.

Q: Q: What causes a valve to leak?

A: There could be a number of reasons why a valve might leak. The most common is a dirty or damaged gate O-ring. The second most common reason could be that the Viton or copper bonnet gasket is also dirty or damaged. Another cause is a leak in the bellows which can be detected with a leak detector on the actuator.

Q: What happens to the gate when air pressure is lost?

Q: What happens to the gate when power is lost?

Q: What causes a valve to leak?

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