The 4-way valve used in the Invacare LX Series and Platinum Series Concentrators does have an acceptable tolerance of leakage.
By nature of the valve design it is possible for the valve to experience small leaks, and still operate without affecting the overall performance of the unit. The valve is assembled together using several parts, meaning the components that make up the valve itself lock together. The only screws in the valve are for securing the valve to the manifold assembly.
According to research there is an acceptable leak specification of 60 cc per minute at 20 psi on each valve. Valves that have leaks within this specification will function properly without any adverse effects to the performance of the concentrator. A leak in the amount of 60 cc or less would be indicative of the type of small leak you would notice where the end caps connect to the main body or where the three pieces of the main body connect together. A 60 cc leak would not be noticeable when examining the system pressure swings.
Leaks greater than 60 cc are indicative of cracks in the end caps, or a blown seal where the end cap connects to the main body of the valve. These leaks are detected by either reading the system swing pressures, noticing two consecutive swings not being equal or by hearing an audible leak every other cycle. Leaks of this extreme nature indicate the valve needs to be replaced.
Valves should only need to be replaced when the following conditions exist:
- A visible crack is noted on either of the end caps or main body, regardless of the amount of leak.
- A large leak is present on the valve that causes an imbalance in the sieve bed swing pressures. Example: Sieve Bed 1 pressure swings from 14 psi to 21 psi, within 7-20 seconds and Sieve Bed 2 pressure swings from 13 psi to 21 psi slowly, and may take as long as 25-30 seconds before shifting (times over 30 second will shut down automatically).
- Valve won’t shift and the pilot valve solenoid and circuit board are working properly.
NOTE: The concentrator’s P.C.B. should exhibit an error code for High Pressure Failure (1 Red/2 Green)