21V51U-843 - Neutral terminals location

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Old 08-04-17, 12:22 PM
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21V51U-843 - Neutral terminals location

I'm replacing the control board of a Trane XV-80 by an OEM universal control board, 21V51U-843.

The NEUTRALS terminals are not identified in the board neither in the documentation. They are just labeled as E21, E20, E17, E18 and E19 in this sequence from the top to the botton.

Their horrible installation manual just says:
- CIRC N................spade terminal...circulator blower NEUTRAL side
- LINE N................spade terminal...input voltage (120 VAC) NEUTRAL side
- XFMR N...............spade terminal...24 VAC transformer line voltage NEUTRAL side
- HUM N (optional)..spade terminal...humidifier NEUTRAL side
- EAC N (optional)...spade terminal...electronic air cleaner NEUTRAL side

Can somebody help me identifying the correct terminals?

Thanks!
 
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Old 08-04-17, 02:15 PM
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Welcome to the forums.

The link below is the installation manual. Page 6 has the terminals identified.
At the bottom of the wiring diagram is a detailed plug view.

emerson climate/Documents/White-Rodgers/instruction_sheets/0037-7115.pdf

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The neutrals are all tied together. You can use any terminal for any neutral use.
 
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Old 08-04-17, 02:46 PM
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Thanks Pjmax for your response.

The diagram at the bottom of the page 5 have the descriptions of the 5-pin and 12-pin connectors. The problem is with the 5 spade terminals. In the board they are numbered as E21, E20, E17, E18 and E19 and the description on page 5 and 6 doesn't associate them with spade terminal numbers.

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Old 08-04-17, 02:49 PM
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Sorry. I didn't see this part before:

"The neutrals are all tied together. You can use any terminal for any neutral use."

Thanks a lot for your help.
 
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Old 08-04-17, 03:30 PM
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No problem. Post back if you have any other questions.
 
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