I wonder if anyone can shed any light on this?
I have a digital variflo controller, controlling a Vyair 5 lpm pump. The pump draws from a 400 litre tank, and then pushes the water through an 11 litre DI vessel, and then on to the hose reel (100m of microbore). What I'm finding is that the flow rate fluctuates during the day: it can start off a little weak, pick up and be fine, then tail off, then pick up etc. The battery (85 a/h) is charged.
I have measured the flow rate at various stages in the system today:
1. From the end of the microbore hose, it takes 35 seconds to fill a one litre bottle.
2. From the end of the DI-to-reel hose, it takes 20 seconds to fill the one litre bottle.
3. Direct from the pump (not passing through the DI) takes 20 seconds to fill one litre.
4. With the microbore pulled right out, 35 seconds.
5. Connected from the DI to a standard Hozelock 1/2" bore garden hose, 35 seconds.
I have recalibrated the variflo.
It appears to me that the problem lies with the hose or reel. It appears undamaged, but is a couple of years old now. Could it have ruptured inside and be partially blocked? It has had a few vehicles over it in its time! Would I be better to switch to a minibore hose? Of course, maybe the pump is getting on and can't push the water out through 100m of pipe. The system has worked fine in the past, and it is only in recent months that it has started becoming a little erratic.
Any constructive suggestions appreciated.