I've been getting the sprayer ready for this weekend but once again I'm being bitten by incompetent designers, engineers, product managers, purchasers or whoever makes/made the decisions at FIMCO. The fancy chart in the Delavan pump manual shows pump output at various rpm, and at 450 rpm it's 8.0 gallons per minute (gpm). Running the tractor at 2,200 rpm turns the pto at about 450 rpm and in M range I have a top speed of about 6.5 mph. All is good .... NOT!!!
The sprayer manual specifically states that the nozzles need to operate at 20~30psi for best performance, but even with the pressure adjustment valve backed out all the way, and pto running at 450rpm, the pressure is 80psi. That's way above the optimal pressure of 20~30 psi, and at 80 psi the sprayer is putting out 1.81 gpm. I measured this by collecting water from one nozzle for one minute and weighing it. At 25 psi the sprayer should be putting out 0.9 gpm. This is messed up!
I called FIMCO this morning and admittedly the second person I spoke with was very knowledgeable and helpful. He listened to my explanation of what I was seeing, and then asked me the size of the return hose from the valve body to the tank. I told him that it's 3/8" to which he told me "there's your problem, and we don't know why we use such a small return hose". He suggested increasing the hose and fittings to 1/2" or maybe 5/8". The pump is circulating water at a rate of 8.0 gpm, the nozzles are supposed to be putting out 0.9 gpm at 25 psi, so around 7.1 gpm needs to get back to the tank, and that 3/8" hose is too restrictive so the pressure increases. So FIMCO makes and sells a sprayer that in its current form won't work at the pressures they say it should be set to. It never ends!
I removed the blower and snow blade last weekend (I think) but yesterday it was like being inside one of those snow globes! It snowed on and off most of the day.
I did manage to make some progress and upgrade some fittings on the pump and the valve body and run new inlet and outlet hoses. I "upgraded" the pressure gauge too but ideally want to use a fluid filled gauge. After pouring over the pump manual, the manufacturer is against the idea of rigidly mounting the pump to the tractor due to alignment issues. It would put too much stress on the input shaft and bearings so it's back to using the chain to prevent the pump body from rotating.