On occasion, a foam concentrate proportioning pump can become stuck – the system powers on but won’t pump concentrate. Why?
This often happens when the system is not operated or exercised regularly.
It might be broken or it might be stuck. Before tearing it apart (costly), 1st see if it is stuck (not costly).
Foam concentrate contains water to aid in keeping it fluid. It is detergent. If the pump system sits for a while and isn’t operated regularly (see manufacturer’s recommendations) the detergent can dry out and solidify. The pump cannot pump solid detergent. As a simple experiment, pour a little dish detergent in a small dish or bowl and let it sit out for a long while. See what becomes of the detergent.
So, what is the solution (pardon the pun) if this happens? Generally, rehydrate the concentrate. Many concentrate pumps are equipped with an “Auxiliary Pick Up” or inlet (generally ¾” ght). All pumps have a “BYPASS” (auxiliary) outlet. Connect a pressurized garden hose to the auxiliary inlet. Make sure the pump outlet valve is turned to the “BYPASS“ position. Make sure the pump inlet valve is turned to the “Auxiliary Pick Up” position. (See Photo below). Place the “BYPASS” outlet tube into a bucket to avoid bubbles all over the ground. Turn on the garden hose, place the system in manual mode and wait.
Depending on how solid the concentrate is, determines on how long it will take to eventually flush out the dried concentrate from the pump. Try to re-hydrate the dish detergent experiment discussed above to see the results. (The above dried detergent was rehydrated and still effective to wash the dishes).
The water pressure and the pump pressure combined will usually pop open the valves, and clean out the dried detergent.
Once it is cleaned, turn the “Auxiliary Pick Up” valve back to the concentrate “Tank” position, get a clean bucket and then run the pump in simulated mode (see manufacturer’s instructions) to re-prime the pump with new concentrate. Once the pump is primed, change the pump “BYPASS” valve back to the inject position, ready to fight fire.
And remember, just like running the fire pump and warming up the compressor, be sure to periodically exercise the foam concentrate proportioner system to ensure it is always ready to fight fire.
If by chance, this doesn’t solve the problem, the pump my be broken. In this case it is best to consult your EVT Foam certified mechanic.
For questions – ASK CAF.
