Hi
We have 2 digital varistreams on the van controlling 2 Shurflo pumps. As Vadim says, the 8000-946-138 delivers 5.2 l/min so we have our flow set at 3 on the varistream. This will give us around 1.5 l/m at the pump outlet and is fine for our brushes with 2mm jets and 100m of minibore hose.
The other Shurflo pump is a 8000-441-138 and delivers 3.8 l/m so we have this varistream set at 5. We have both the Varisteams pressure settings at 8 as this works well for us as the pressure is fine for 2 storey work and not high enough to keep blowing the Hozelok fittings off the van to hose reel coupling hose.
We can set the flow up a couple of points if needed but very really do, even on new cleans. You may find that if your hoses are a different length and size to ours your setting will probably be a little different. Flow rate is a personal thing. If you have too higher flow rate you waste water and you will waste time with too lower flow rate, especially when rinsing. As you gain WFP experience you will get quicker and will probably increase you flow rate with time anyway.
We try not to take on one off cleans if we can help it. On a first clean, we usually give the frames and windows a good clean and then give them time to drip down and dry off. We usually tie this is with our regular work, so do the first clean in the morning and then come back to it later in the day and do it again if necessary - find it works fine with domestics this way. We find most normal UPVC windows are fine, the only problems these days come from the windows that have 2 openers above a main glass panel below. We initially wash the whole window, paying special attention to the frames above these quarter windows and rinse very well. When we come back we will just do the bottom window again if the quarter windows are fine. On subsequent cleans we clean the top quarter window frame, but not above it and once every third visit will wipe the top frame above the quarter windows with a damp cloth.
Your priority is to gain experience and keep waste water to a minimium as you have a limited water supply with a trolley.
Take your time, do the job properly with your first clean and the future cleans will be a piece of cake.
Spruce