If valve won't flow until I unscrew the solenoid, which part has failed?

[Pman6]

I have some Toro valves installed in 1992. They are one-piece and can't be taken apart. The only thing user replaceable is the solenoid.

It does not use the universal solenoid you can find at big box.

one valve will not open unless I unscrew the solenoid. It will just dribble water otherwise.

I swapped the solenoid with one on another working valve, and the valve still won't open.
I even swapped the wires to another working station and the valve won't open.


But as soon as I loosen the solenoid, the valve flows full blast.

I even removed the solenoid and let the water spray out everywhere to clean it out.

I'm out of ideas.

 

[WorthFlorida]

Without pictures or model number of valve, it seems that it is time to replace the valves. Either debris is jamb in the valve or the diaphragm is dried out. I'm suspecting the diaphragm is the problem. You can try to clean out the bleed valve port if there is one and the solenoid dump port. Use a very small drill bit and push it in the hole for the solenoid. It might clean something out.

 

[Sponsor]

 

[Terry H]

Check voltage to make sure you are getting voltage to solenoid. If you are then your solenoid has failed and isn’t opening. If it’s not you have a control problem.

 

[Pman6]

I swapped the working solenoid+wire from the other valve over to the bad valve, and it still didn't open.

so i think that eliminates the solenoid and control.

tested voltage at 26V

 

[Terry H]

Ohhh I’m sorry I’m not sure how I missed that.

This is strange. The only thing I can think of is that there is trash inside of the body.

 

[Pman6]

yeah well, the diaphragm isn't accessible.

so looks like I'm gonna have to swap in a rainbird.

 

[WorthFlorida]

Those are valves are with an anti siphon device. You need to change the entire top unit. Since they are mounted like that it be nothing to change them out with new ones. The only problem might be spacing. The 1" rain bird unit is center of inlet to center of outlet: 3.84".

https://store.rainbird.com/dasasvf1...RoCqkgQAvD_BwE#product_tabs_additional_tabbed