CVA24-T Actuator Details

[JoyfulNoise]

Does anyone know if the 24VAC power to the CVA needs to be balanced across the three wires -

L1 - 12VAC
COM - 0V
L2 - -12VAC

or does it just have to be 24VAC across the two “hot” leads? I ask because I have some old defunct CVA’s that I’d like to bench test and I have a 3-wire 24VAC plug in power supply that has two hot leads and a ground (not a common). Unfortunately the AC isn’t balanced with respect to ground terminal.

 

[JamesW]

You should get 24 VAC between one of the switched legs and common.

The switched legs are connected to one side of the transformer output by a single pole double throw switch so that only one leg is powered at a time.

If you apply power to one switched leg and common, the actuator will rotate in one direction.

If you apply 24 VAC between the other switched leg and common, the actuator rotates the opposite way.

 

[sevans01]

1 leg of the 24VAC would go to common the other leg is switched between the "hot" leads to control direction. ie- applied to 1 lead goes clockwise, the other lead would go counterclockwise

 

[JoyfulNoise]

So if I connect one wire from the power supply I have to the center common and the second wire to one leg, can I run a small jumper wire over to the other leg so that there’s power to both sides? That should work, no?

 

[Jimrahbe]

Matt,

Here is a schematic of a possible test jig if that helps..

img080-1.jpg

• Jimrahbe
• Nov 19, 2020

Thanks,

Jim R.

 

[JamesW]

So if I connect one wire from the power supply I have to the center common and the second wire to one leg, can I run a small jumper wire over to the other leg so that there’s power to both sides? That should work, no?

No, you only power the common and one of the switched legs at a time.

 

[JamesW]

As shown in the diagram, black gets one leg of the transformer output and the other leg of the transformer output is connected to either the red or the white wire depending on which direction you want the actuator to turn.

 

[JamesW]

The actuator will turn until it trips the microswitch.

To reverse the direction of the actuator, you can change which switched leg gets power or you can use the small toggle switch on the actuator to change the direction of the rotation.

 

[JoyfulNoise]

So what does the Easytouch panel output to the three wires?

 

[JamesW]

The Easytouch is continuously sending 24 volts AC to the actuator.

From the Easytouch transformer, one leg is always connected to the black wire.

The other leg of the transformer is connected to the red or the white wire.

The switched leg is switched by a single pole double throw switch in the Easytouch.

 

[Jimrahbe]

Matt,

The EasyTouch has some small low voltage relays that drive the actuators.. The relay switches one side of the 24 VAC between the Red wire and the White wire. When the Red wire is hot the valve move one way and when the White wire is hot the valve moves the other way. The Black wire is always hot.

Thanks,

Jim R.

 

[JoyfulNoise]

Thank you all!!

My brain had the wrong wiring diagram in its imagination. I forgot to consider both the manual switch and the relay board. Two is one too many degrees of freedom for me

They should just use gremlins to do the switching next time ...

 

[JoyfulNoise]

Moly sulfide grease in the gear box or should I use white lithium grease

 

[Jimrahbe]

Matt,

Really??? I suspect you are the only one here that even knows the difference between the two..

I know for sure that I don't..

Jim R.

 

[JoyfulNoise]

Matt,

Really??? I suspect you are the only one here that even knows the difference between the two..

I know for sure that I don't..

Jim R.

If the gears are metal, I’ll go with MoS2 grease because .... I happen to have some and the AZ sun is hot enough that having the high temperature rating couldn’t hurt .... if I see any plastic gears I’ll go with lithium grease.

Next question - anyone know the rating on the capacitor ?? I’m measuring it out to be ~ 36uF and the series leakage resistance is about 1MOhm ... I would have expected the series resistance to be higher. It’s probably fine but I wanted to know if the capacitance was within the expected value. The marking on the capacitor are “cryptic” at best ...

 

[JoyfulNoise]

Nevermind, figured it out.

A 336K capacitor is 33,000,000pF +/-10%. That’s 33uF. I’m measuring 32.9uF (not sure where I got 36uF from .. ). Well within spec. Cap is good.

 

[JamesW]

What is the value in yoctofarads?

*First use (and probably last use) ever of the word yoctofarad.

 

[JoyfulNoise]

What is the value in yoctofarads?

*First use (and probably last use) ever of the word yoctofarad.

My abacus can’t display that many zeros ...

 

[JoyfulNoise]

So my motivation behind all of these questions is this -

Because Pentair is heavily pushing their IntelliValves, which are anything but intelligent, you can no longer find CVA actuators for less than $200. A few years ago, you could easily get a CVA for around $120 or so. Not cheap, but not a wallet-buster either. Well, try finding a new CVA for anything less than $200 .... you won’t.

So I have gathered a few old CVAs and intend to build up a spare to keep on hand. If I can find some internal rebuild kits on eBay, I’ll grab what I can. There’s simply no good reason to switch to IntelliValves when they offer no advantage for my EasyTouch automation system. Someday I may upgrade to an IntelliStation but that’s many years away at best.

 

[JamesW]

I bet we can find a manufacturer that can make these for a reasonable price.

Sell at a reasonable discount and make a fortune.