what benifits do you get from having a varistream or similar systems fitted to wfp systems , can a systems work ok not having one fitted
Tolwoods,
I think you have four options:
1. No flow control.
2. A varistream.
3. A flow restrictor (such as is shown in P & F's picture above).
4. A flow restrictor with a pump bypass.
Using no flow control will mean that you will pump water out at a huge rate of knots. My 60 psi shurflo will emit 7 litres per minute, when I think 2 litres is enough for me. If I had a 650 litre van-mounted system, then this wouldn't be a problem.
A varistream, from the posts I've read here, seems to be the best option. I haven't a clue how to fit one though.
A flow restrictor will reduce your water output, but it may also damage your pump, since your pump is attempting to take more water in, than what it's pushing out. When I attempted to restrict my pump with a ball valve I found it 'cycled' (it pulsed and didn't sound very healthy and my water jetted on and off; like a heart beat).
A flow restrictor with a pump by pass works, if you can do it. I've seen a comercially produced one (Peter Fogwills) and that worked fine. My poor attempt was useless; but if you're good at DIY stuff, this may be a good option; especially if you're on a budget.
E-Mail Matt (that's his user name) and he'll show you how to do this.
I hope this helps.