Unneeded Solenoid?

[Rudy]

Can anyone tell me why my car wash was built with a Normally Open solenoid located between a weep check valve on the high pressure pump output, and the main weep feed line.

This solenoid IS NOT the main, normally open valve which the WeepMiser cycles on and off.

The solenoid I am referring to is wired to the motor starter of my Cat 623's for the self serves, and the Cat 3535's of my automatics. This valve close whenever the pump comes on.

Why would a solenoid be needed? A paraplate check valve prevents the pump back feeding the weep line.

It seems to me to be unnecessary and redundant....yes?

Anybody have a set up like this?

 

[2Biz]

My Mark VII has the same valves, one for each weep line. I believe it shuts the weep off to keep from diluting and contaminating LP functions...Spotfree rinse and presoak...

 

[Earl Weiss]

When the pump is running the Solenoid is energized and closed. No need to be running weep thru that line if the pump is running. My foam brushes have the same thing.

 

[Rudy]

Thanks for the reply, but I still don't understand. This valve CLOSES, when the HP pump runs which isolates the weep line from the HP pump. This weep line, however, should already be isolated due to a check valve.

Also, LP functions are isolated by their own respective check valves (which are closer to the bays).

There's no way to have ANY LP function touch this solenoid unless there was a check valve failure (for me, it's on the roof in a trough just above each bay), then the LP would have to backfeed to the equipment room, and then ALSO backfeed a failed weep check valve.

The only thing I can figure....is that it serves as a back up to prevent a weep line from breaking (due to overpressure from an HP pump) IF the check valve fails to do it's job????

 

[car washing systems inc]

It sounds like a trickle sol that will close when a low pressure function is used if your weep water is at a higher pressure it could dead head. Ginsan and D/H use this set up. What make are your pump stands?

 

[cantbreak80]

Check to see if the solenoid is energized when low pressure product is selected. If so, it's to prevent weep water from over-powering the low pressure delivery system.

And btw...a closed solenoid valve will be forced open if the outlet pressure exceeds the inlet pressure. So, your thought about it serving as a check-valve back-up would be incorrect.

Also, you'd want your weep supply lines to break if the weep check valve fails...otherwise high pressure water/soap/wax can be forced backwards into your water softener, boiler, ro system,... and even the city main (if you're not equipped with a really good backflow prevention device).

 

[MEP001]

I've seen a lot of washes set up like that. Usually there is no check valve on the soap and wax lines and the weep goes into the pump at the same point and not on the outlet of the pump. If the weep does go to the pump outlet, you're correct that it's completely unnecessary. If it goes to the inlet, it needs the solenoid to keep the weep from diluting the soap and wax.

 

[Rudy]

My pump stands were made by Pro Equipment twenty years ago.

My original LP functions were set up with a Myers style pump with air bladders plumbed onto the outputs.

Ten years ago, they were replaced with ARO diaphragm pumps for everything except my Self Serve Presoak system.....which uses a FloJet pump.

My weep pressure is in the 45psi range....and the LP pumps are running well above that.....which supports my belief that these "pump located weep solenoids"....are unneeded.

FWIW, I will check to see if they are wired so that LP functions will activate them. That would be another clue.

 

[MEP001]

FWIW, I will check to see if they are wired so that LP functions will activate them.

If they're wired through the motor starter, they probably don't activate with the LP functions. Older D/H equipment has a box that it's wired through with all the LP functions tied into it so any of those will close the weep solenoid.

 

[Rudy]

I just checked, and yes, the solenoid activates (closes) with LP functions.

Would you agree, that, since my system uses LP functions at a pressure higher than the weep pressure....these solenoids are not necessary?

One of the reasons I am asking, apart from obtaining an understanding, rests with needing to replace one. I found one whose inner workings is basically shot. I don't feel like buying a replacement solenoid if it's not needed.

 

[MEP001]

I'm running about a 15 PSI difference between the weep and the LP functions and there's no issue with the weep diluting the tire cleaner or presoak. So yes, I think you can safely delete them. You can always add a regulator on the weep and lower the pressure more if you need to.