cmcardle75
LIFE MEMBER
I'm just building a new Movano PVC. I specced up a Shurflo 2.1 bar pump and a Fiamma A20 accumulator from the start. However, on first test (only the wash basin taps available yet), there was extremely rapid (i.e twice per second) cycling from the pump, even at full flow. Even after turning the tap off, there would be a couple more cycles as it built up pressure.
After a bit more testing (i.e. just using a free flow hose as the only output), it became clear that with the accumulator removed, the pump would only cycle below a certain flow rate, controlled by sticking a finger on the end of the hose. However, with the A20 installed, it would ALWAYS rapid cycle, even with the hose unrestricted. After finding this, I bypassed the A20 in the system and the basin tap now works without cycling, provided you open it at least halfway. The pump now also turns off immediately the tap is closed, rather than having another 3 or 4 bursts.
Is the A20 faulty? I'd like to have the benefit of an accumulator to allow taps to be partially open. It's almost like it is acting like a big air bubble, causing rapid changes in pressure, rather than as an accumulator, absorbing changes. I tried changing orientation to release any trapped air, but there was no effect. The preload pressure was checked and a few different pressures attempted.
After a bit more testing (i.e. just using a free flow hose as the only output), it became clear that with the accumulator removed, the pump would only cycle below a certain flow rate, controlled by sticking a finger on the end of the hose. However, with the A20 installed, it would ALWAYS rapid cycle, even with the hose unrestricted. After finding this, I bypassed the A20 in the system and the basin tap now works without cycling, provided you open it at least halfway. The pump now also turns off immediately the tap is closed, rather than having another 3 or 4 bursts.
Is the A20 faulty? I'd like to have the benefit of an accumulator to allow taps to be partially open. It's almost like it is acting like a big air bubble, causing rapid changes in pressure, rather than as an accumulator, absorbing changes. I tried changing orientation to release any trapped air, but there was no effect. The preload pressure was checked and a few different pressures attempted.
