Selector Switch NC Block causes RTD issues

[cod3ck]

So I’m building a control panel ideally focused around a single EZBoil.

I have two RTD’s for measuring temps. One in the BK, the other in the RIMS tube.

If I wire line #3 of each RTD through a separate NO selector block on a 3 selector switch, the temperatures for each probe look fine.

If I try and wire one through an NC block though so I can trigger connection when the selector switch is set In the middle, the temperature on the EZBoil goes haywire.

Is this a known issue w/ NC Selector switch blocks? What am I missing?

 

[schematix]

provide pictures or diagram please.

sounds like classic RTD wiring error.

 

[cod3ck]

Expected test temp w/ NO selector block

Unexpected test temp w/ NC selector block

 

[schematix]

picture of the wiring....

 

[schematix]

actually re-reading your post..... your error is simple. you need to switch all 3 RTD wires.

 

[cod3ck]

actually re-reading your post..... your error is simple. you need to switch all 3 RTD wires.

Nice!

I thought about this, but it didn’t make sense to me that the NO connection appeared to work successfully with just the last wire on the switch (instead of having to switch all 3 on their own separate blocks)...?

I’ll give this a shot — thanks!

 

[cod3ck]

No luck...

I set all three “center” wires onto their own individual NC selector blocks and I’m still seeing the same result.

The only other outlier I can see is the NO block still only sets wire #3 for the “left” wires...

That said, I’ve pretty much maxed out my depth in an 8” box. So that solution isn’t an option...

Anyone thoughts?

 

[schematix]

It needs to be wired like this. Sorry MSPAINT the best i can do at the moment.

So when your switch is in say the left position, the 3 NO blocks are open, and the 3 NC blocks are closed, giving you RTD 2. When you move the switch the other side the NO blocks close while the NC blocks open. That gives you RTD1.

 

[cod3ck]

Bummer [emoji13]

I was hoping to avoid this due to the depth the blocks take up... Looks like I need to take another route.

Thanks @schematix!

 

[schematix]

you could do 2 plugs/sockets and manually switch as well.

 

[TexasWine]

So it ended up not working?

The little switch I sent you a link for works great, and I just use lights to tell me which probe the controller is lined up to.

Here it is in action. Hard to see, but it's flipped over to the right, which is the HLT/BK.

 

[cod3ck]

I was originally trying to hook into the selector switch already available. This appears to definitely be a much better option... thanks for the reminder @TexasWine!