Boiler Wiring

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Dexie123

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I don't have alot of boiler wiring experience but doing one from my cousin...

Question(s):

Doing a low water cut off for the boiler. It needs to be incorporated with the gas burner. (Using a common 24 Volt power supply)



Right now the way it is wired is that the boiler's control box has two wires going from it's B1 and B2 terminals to the gas burner's TW and TR.

In the image uploaded (I hope) it shows to incorporate the low water cutoff by attaching my burner wires to the low water cutoff's control box and attaching to 2 and P2.

My question is this: It's not abundantly clear to me if I pull the wires off of the boilers B1 and B2 terminals and reroute them to low water cutoff control box and then attach them to 2 and P2 or do I just break one leg of TW or TR and reroute like a switch into the low water cutoff control panel? The former seems to be the way it's wired to me but would sort of make more sense that it should be controled by the boiler control box directly.

Also the burner circuit is showing me that 2 needs to be hooked up to the burner circuit's common although I am unsure if the TW or TR is considered the common?

(I can't seem to be able to figure out how to insert an image so any help with that would be appreciated)
 
The easiest way is to scroll down to the "Additional Options" window in the "Reply to thread" screen, and upload the image to the website as an attachment. Click here to see the window I'm referring to.

Note that it has to be one of the accepted types of file:
.bmp .doc .gif .jpe .jpeg .jpg .pdf .png .psd .txt .zip

A picture would help in this case. :)
 
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Most of the gas furnaces I do have a transformer built right in for all the electronic controls, so I just break R on the transformer, I use a low voltage low water cut off also, if your using a high voltage low water control then just break B1 in the control box... I would recommend just breaking L1 but the problem is the low water cut off is only rated at 5 amps, and I have no idea what your load is going to be...
 
georgestolz said:
The easiest way is to scroll down to the "Additional Options" window in the "Reply to thread" screen, and upload the image to the website as an attachment. Click here to see the window I'm referring to.
Click to expand...

At the risk of looking completely incompetant I must admit I do not see this part of the message board. I see "Post Reply" at the very top but not "Reply to thread". When I see "Post Reply" and I click on it it doesnt direct me to any "Additional Options".
 
stickboy1375 said:
http://www.mcdonnellmiller.com/pdf/lit/RBC3.PDF wiring diagram for you...
They make a factory harness now also so no need to cut and splice...
Click to expand...

Thanks stickyboy (If that is your real name)

It appears from that diagram on page 2 with the 24 diagram that the "other limits" would require to break the hot leg (or in Low voltage the 24v not the common leg) and put the switch in series.

This leads me to question 2. Which part of the burner, the TW or the TR, is the common?

My kingdom to learn how to put my diagrams online!!!
 
check it out Your WHITE,RED and GREEN is your 24Volt power in and your yellows are your controls remove or cut wire between B1 and TR and use one yellow to B1 and the other to TR. all you are doing is breaking circuit.
 
Dexie123 said:
At the risk of looking completely incompetant I must admit I do not see this part of the message board. I see "Post Reply" at the very top but not "Reply to thread". When I see "Post Reply" and I click on it it doesnt direct me to any "Additional Options".
Click to expand...
If you click on
reply.gif
at the bottom of the replies of the screen you're looking at now, it will send you to a new screen, where you type in your reply.

The heading of the window that you type into is called "Reply to Thread". Scroll down, below where you type, below the smilies, below the "submit reply" button that creates a post from what you typed.

Immediately below this window, there is another window just like the "Reply to thread" window. This is the "Additional Options" window. Your screen won't look completely identical to mine, because the picture I took (with the red arrow on it) was taken on a Macintosh machine.

Immediately below this window is a recap of the last 10 posts to the thread, called "Topic Review". If you're looking at posts, you've gone a little too far, scroll back up.

Edit: In this picture you can see where you type immediately above the "Attachments" button.

If that window does not exist in your screen, perhaps you have selected the super-basic text editor in your profile? You want to have the Standard or Advanced "WYSIWYG" (What you see is what you get) option selected in your preferences. Click here to see your forum viewing options, and go all the way down to the bottom. If you have the "Basic" editor, you might not be seeing the window on account of that.
 
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Thanks George... I'm so stupid!

Anyway here are the diagrams..


The 1st one shows just the basic what the switch is supposed to do. Simple enough

The 2nd one looks to me to show that the water limit switch needs 24 volts to make it operational and the other two legs in series with a broken TR leg according to oscarmal?

Sound about right? Sorry for the technical deficits!
 
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