Glossary “check relay” Definition:
Term often used for check-valve relay or vacuum-check relay.

Glossary “check valve” Definition:
1). Valve that permits the passage of a gas or fluid in one direction but not in the other. 2). Device located in the liquid line or inlet to the drier of some systems to prevent refrigerant flow in the opposite direction when the unit is turned off. 3). Device that allow vacuum to be maintained in a brake booster after the engine has been shut off.

Glossary “check valve relay” Definition:
Electrical switch to control a solenoid-operated check valve.

Glossary “check ball” Definition:
1). Device that maintains air or fuel pressure at a predetermined level. 2). Device that permits the flow of fluid or vapor in one direction only. 3). Type of hydraulic valve, consisting of a ball, that seals an orifice or passage to prevent flow in one direction.