"KurtG" wrote in message ...
Pszemol wrote:
I have noticed relatively cheap fuel pumps on eBay...
So recently new BOSCH pump for $50 which can deliver 80PSI.
I was thinking if such pump could be used for boosting
tap water pressure before RO/DI filter...

I bought my pump on ebay for $80. It included a solenoid and pressure
switch to turn the pump off when the back pressure hits 40psi. I think
you'd need these to turn the pump on and off when needed.

I tried one pump of this kind but it was constantly cycling
between on/off states so is was very noisy driving me nuts :-)
The switch aparently was turning the pump on for about 1/4 second,
then the pressure build up turned of the switch and after about
another 1/2 second the pressure was down (water was "consumed"
by the RO filter) and the cycle repeated over and over again...

What pump have you got ? Manufacturer ? Model number ?
What RO system do you use it with ? Is RO filter 60gph or 100gph?

I've also heard that fuel pumps use the fuel as a lubricant/coolant.
I'd venture a guess that they wouldn't stand up to water due to corrosion.

You are probably correct. I did not think of corrosion :-)