Return to the Irrigation Forum | Post a Follow-Up

Irritrol RD900 Solenoid Chatter

Posted by fullerlee CA (My Page) on
Thu, Jul 12, 07 at 13:28


I am trying to diagnose a problem with my sprinkler setup, controlled by a Irritrol RD900.

When a particular valve is set to ON, the valve solenoid chatters (i.e. they fluctuate between on and off), this causes inconsistent water flow, and a fair bit of water hammer.

I've brought the Solenoids up to the control box and wired them directly to the terminals and they still exhibit chatter .

Measuring the voltage coming out of the terminals, it wavers around the 20vac mark, occasionally dropping to 0.

I've tried plugging the Controller into a different outlet to no avail.

Any ideas please?



Follow-Up Postings:

RE: Irritrol RD900 Solenoid Chatter

fullerlee, it is unclear whether the chatter is associated with a particular solenoid or all of them. If it is with one only, then substituting another will tell you if it is a 'solenoid' problem or a current supply problem. If it happens to all of the solenoids, then it is a problem with current from the clock. If it happens on one valve only, regardless of the solenoid, then the problem may be narrowed down if you wire the zone to a spare terminal in the clock (if one is available). If a spare is not available, wire the zone to an existing terminal and see if the problem goes away. If it does not, the problem most likely exists in the zone wire itself.

RE: Irritrol RD900 Solenoid Chatter

Hi Lee
I just went through the same nightmare ....
In my case it was the very expensive Rd 900 that is fried
I checked both the solenoid and the other parts of the valve. This Rd 900 is about 8 yrs old but has had a very easy life. Sadly I had a feeling something was a bit off. When I would change the zones with that crappy dial, the LCD would display other zone times and it couldn't seem find its proper place. I am really kind of bummed as this controller runs around 180+ dollars. I am sure this is your problem because I was getting the same clicking on all the valves. I hope this link below will help you
Kind regards

Here is a link that might be useful: Troubleshooting irrigation valves

RE: Irritrol RD1200 Solenoid Chatter

I also have solenoid chatter. Started a month ago. It's on all circuits. When I check the controller module, I find the gate signal going to the triacs to be faulty. Instead of this being pulled low (to turn on a circuit) it jumps around (measures .5-1.75 volts) causing the triacs to go on and off (causing the chatter). I'd like to put a scope on it to see exactly what's happening but don't have one. Does anyone have any idea what might be wrong? I have not been able to find the details on this cpu (S3C7C48E70-QWR8) so I don't know what is driving the output pin(s).

RE: Irritrol RD900 Solenoid Chatter

I had the chatter issue on my RD900 after about 10 years. The voltage from the transformer was 25v but the output to the solenoids was 12-14v pulsing about twice per second. I called Irritrol (Toro) and they quoted me a maximum of $65 to repair it. I sent in the module and circuit board and got a call in two days saying it was done. Unfortunately, the service department said it was a flat rate of $85.

The tech there said that a marginal solenoid could cause the triac to blow and told me that they should be tested yearly. He said to run a solenoid for about 10 minutes to bring it up to temperature, then when it goes off, test the resistance at the controller terminals. Should be between 15-50 ohms to be in spec. If not, replace the solenoid.

RE: Irritrol RD900 Solenoid Chatter

I just had a second RD1200 fail with chattering solenoids (all circuits). I took the unit apart (carefully) and checked voltages. I found 25vac on the + side of capacitor C5 (220uf) instead of plain DC. Replaced this with a new one ($1.5 at Radio Shack) and it is working fine now. Thought I would let people know...

RE: Irritrol RD900 Solenoid Chatter

I have an RD1200 controller it has been working for about 7 years. All of sudden all solenoid valves started to chatter. But timer indicator seems normal, clock running normal. Replaced 9 vac battery any way and no change. I put system into manual control testing one output at a time. I put an AC voltmeter measuring an output terminal to common wire. On one terminal I got 13 volts and I expected around 24. I checked transformer input it was at 26 vac. I had another circuit where sprinklers were pulsing with a period of about 1 second between pulses of water and that terminal voltage would cycle every second between 9 vac and 0.5 vac. I removed digital electronic portion fromm unit detaching ribbon cable. So I am operating sprinklers by applying 24 ac directly to each solenoid with clip leads and all solenoids work
fine no chatter and sprinklers turn on.
The digital controller keeps time perfectly, it cycles through program as defined. I think the output Triacs switching the 24 ac are not functioning.
Does anyone have a circuit diagram for the output board?

RE: Irritrol RD900 Solenoid Chatter FIX!!!!

Just fixed my Rain Dial RD900 With the chattering solenoid problem with the capacitor fix from ccalkins << THANKS FOR THAT FIX. Its a $1.67, 220uf, 35 volt Axial capacitor at Radio Shack as stated and you need to solder it in. That's all those repair shops are doing for $35.00 to $85 Dollars!!! You need to open the unit by pressing in on the clips (3 on each side) while prying the unit apart at grove around the middle (1 clip at a time). 2 screws to get the board off. It's Marked C5. Solder in the new one. Watch polarity! When putting the board back in, make sure you line up the slide switchs on the board with the slide "covers" in the front panel (the ABC and Run/Off switch). Snap the back on again, DONE!!!!

This post was edited by Rickinphoenixaz on Sun, Apr 27, 14 at 19:35

RE: Irritrol RD900 Solenoid Chatter

I just fixed my RD-900 for $13.00 and one hour of time all my problems are now gone from chatter to display issues and in some cases the sprinklers not coming on. I followed ccalkins post from Fri, Jun 14, 13 at 11:12

I just had a second RD1200 fail with chattering solenoids (all circuits). I took the unit apart (carefully) and checked voltages. I found 25vac on the + side of capacitor C5 (220uf) instead of plain DC. Replaced this with a new one ($1.5 at Radio Shack) and it is working fine now. Thought I would let people know...

It cost me $13 because I had to purchase a soldering iron as well.

 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!

Return to the Irrigation Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Please review our Rules of Play before posting.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.

Learn more about in-text links on this page here