I thought this may deserve a new post.
Mick (UHPS) cornered me in another thread to contact Williamson's Pumps and find out if the warranty was valid for their back pack for use as a water-fed pole 'power pack' (ie pump, batter and water container).
I didn't think it was because it's primary design is for crop spraying. I assumed that since we adapt it for a purpose other than it's original purpose the warranty would be invalid.
Anyway, after a conversation with Martin Burrows (Williamson Pumps) I found it actually IS valid.
Martin said the following:
Only those bought with a CE mark will be covered. So those back packs purchased from E-Bay USA wouldn't. I think he did mention something along the lines of someone in the UK has bulk purchased a load from the US and is selling them on; these wouldn't be covered either.
They know what window cleaners use the Shurflo for and are quite happy to honour the warranty (purchased from the correct place).
They will adapt the back pack for window cleaners for an extra £18; and have done quite a few already. He didn't seem overly keen on doing this though. He said once they'd made the adjustment, it's impossible (or difficult) to return it to a crop sprayer (but I don't think there's too many crop-spraying window cleaners about).
I paid £217.38 in total (VAT and postage included) for mine.
It's a cracking bit of kit and I'm well impressed it's covered by a warranty still.
If anyone is interested:
The phone number of Williamson Pumps is 0845 2263638 (Martin Burrows).