2 functions operating one solenoid. 24v question?

[hoyeman]

I am switching over to a tankless system and will have my wax and rinse setting open one solenoid valve for cold water. How to I make sure my solenoid that allows wax to be drawn in doesn't open when the selector is set on rinse? I am picturing the current going to the cold water solenoid and sending a current to the wax system which will open the wax solenoid. How do I isolate that solenoid?

Thanks

 

[MEP001]

Use a SPDT relay. You'll input the voltage for one function to the NC on the relay, the other function to the coil and looped to the NO, then the output to your cold water solenoid. Whenever either function is selected the solenoid will get power with no cross-current between them.

 

[hoyeman]

Thanks MEP,
Is there a brand that you prefer?

 

[lag]

he is refering to a single pole double throw relay. any brand will do. look in the grainger cat. and you will find what you need. Good luck

 

[MEP001]

I got some Omron from mouser.com that were only about $6 each. There's no real load on it so it will last almost forever.

You might have trouble finding SPDT from Grainger. You'll end up getting DPDT and paying more.

 

[MEP001]

I've used these two types:

http://www.mouser.com/ProductDetail...=sGAEpiMZZMtSzCF3XBhmW15747hehDm9nQ54aFPVwsY=

http://www.mouser.com/ProductDetail...=sGAEpiMZZMtSzCF3XBhmW4v1FonduN8Df4mJm7nByRo=

The main difference is connecting them. The first one has to be soldered which is pretty easy to do. The second either needs a base to plug into or spade terminals crimped onto the wires.

 

[2Biz]

Use a SPDT relay. You'll input the voltage for one function to the NC on the relay, the other function to the coil and looped to the NO, then the output to your cold water solenoid. Whenever either function is selected the solenoid will get power with no cross-current between them.

I stumbled across this post. It took me a few minutes to understand after mapping it out, but this is the cats A$$ for isolating a solenoid with (2) inputs. Thanks! I was planning on using (2) relays to do the same thing...

 

[MEP001]

It should be the same basic thing as using a SPDT relay to switch on a cold water solenoid when the soap is NOT energized, as in this diagram I posted before:

 

[2Biz]

Similar..Except I'll be switching between Rinse and Wax to the cold solenoid. Rinse will be NC, Wax will be NO tied to the coil, output goes to the cold water solenoid....In your diagram, the coil is not tied to the NO leg of the relay....

Thanks again for the post, I've never looked at it that way before.