Taco EBV zone valve?

[Bricks]

I am using the EBV valve for boiler temperature control. It needs the dry contact points with power to find it`s proper operating position. Since I don`t need the dry contact how can I fool it so it can find it`s proper position?

Thank You

 

[Gooserider]

It would probably be worth sending a note to Taco tech support - I looked at the wiring diagrams quickly and didn't see anything that really said. I also didn't see anything about actually needing to have the dry contacts powered to find it's "home" position - as I interpreted the instruction sheet it appears that finding "home" is a function of the position sensors inside the controller electronics. There was a mention that you could get a "false alarm" contact closure as the valve determined it's home position on initial power up after installation.

Just guessing here, but if it DOES need to have power on the end switch contacts, I would suspect that you could just jumper the hot side of the transformer to one or the other of the end switch terminals, and possibly then go through a big resistor on the other terminal to the other power terminal... (Make sure you put some kind of resistance there or you will short out the power supply!)

BTW, Are you sure the EBV valve is the right thing for the application? Zone valves are generally on/off flow control with a significant time lag on the open and close steps. Most of the layouts I've seen use a mixing valve or other similar item that gives a gradual flow control so that you mix in just enough hot water at the return to keep the boiler temps right... I like the EBV valve concept, but only in places where it's use is appropriate.

Gooserider

 

[radarblip]

I am using the EBV valve for boiler temperature control. It needs the dry contact points with power to find it`s proper operating position. Since I don`t need the dry contact how can I fool it so it can find it`s proper position?

Thank You

Bricks:

I've installed these in my heating system for 4 years now and had a failure of the actuator. I replaced it with a new actuator and, being the inquisitive type opened the old unit up. How the ball valve finds its state of closure is with a photoeye that is blocked when the ball valve is closed. the dry contact end switch merely indicates closure of the valve. You can't "modulate" this valve. Applying 24vac to the power terminals will operate the valve to either its full open or closed position, depending upon which valve model you have, either normally open valve model or normally closed model. Deenergizing the power contacts allows the valve to return its original state. I used normally open valves so in the event of a power outage all valve open and uses all my radiators in my home as a heat dump zone. Hope this helps.

Bob

 

[Bricks]

Radarblip wrote
" How the ball valve finds its state of closure is with a photoeye that is blocked when the ball valve is closed. the dry contact end switch merely indicates closure of the valve."

According to directions on intial energizing it needs the dry contact switch to find it`s home postition. After that it seems good to go.

I am using a zone valve to modulate my return tenp to my Echo 40. My underground run is longer then I want and from reading about mixing valves some feel they create extra head pressure.

 

[Gooserider]

Radarblip wrote
" How the ball valve finds its state of closure is with a photoeye that is blocked when the ball valve is closed. the dry contact end switch merely indicates closure of the valve."

According to directions on intial energizing it needs the dry contact switch to find it`s home postition. After that it seems good to go.

I am using a zone valve to modulate my return tenp to my Echo 40. My underground run is longer then I want and from reading about mixing valves some feel they create extra head pressure.

I think you are misreading the directions.. Even though the ball valve will have two equivalent open and close positions, the actuator will want to only use one. Depending on just where in it's rotation the valve shaft is, the actuator may need to turn the shaft more than 90* to find it's preferred home position. If so, you can get a momentary closure of the end switch as the actuator is finding the home position. The valve does NOT need or use this closure for anything, it is a side effect of the actual mechanism inside the actuator doing it's thing... However, IF you have the boiler or other stuff hooked to the end switch, then the momentary closure can cause the boiler to short cycle... The instructions mention this possibility only to indicate that it's a normal part of the switch operation, and not a problem... (So that the installer doesn't try to troubleshoot a non-existent failure)

As to the mixing valve causing extra pressure problems, that shouldn't be an issue if one uses the right valve and plumbing setup... OTOH, I don't see how the "bang-bang" nature of a zone valve will really help with the return protection, which normally would want a more gradual control... Post a diagram of your layout, and we will see if we can come up with a better solution.

Gooserider