Check Valve
Remove check valve from system. Blow through valve in direction of air pump air flow. It should flow freely. Turn valve around and blow through opposite side. No air should go through. If valve acts in any other way, replace it.
Remove check valve from system. Blow through valve in direction of air pump air flow. It should flow freely. Turn valve around and blow through opposite side. No air should go through. If valve acts in any other way, replace it.