Wiring line voltage thermostat for FCU.


  #1  
Old 06-25-22, 05:07 AM
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Wiring line voltage thermostat for FCU.

Hi,

I'm moving from an old Honeywell T6575D1009 to a new Emerson Sensi thermostat. I think I've figured out some wires on my own, but would appreciate some validation and help with the ones I'm not so sure about.

I'm attaching pictures of the old wires and the new Sensi system.

From what I understand, Sensi does not support 3 speeds, so I'll need to choose a speed and then ignore the other two fan speeds.

Ty for any help.




 

Last edited by PJmax; 06-25-22 at 01:32 PM. Reason: enhanced pic
  #2  
Old 06-25-22, 06:42 AM
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Sorry.... the Sensi will not replace that thermostat.
The T6575D is a 120vAC fan coil thermostat.
The Sensi is strictly 24vAC.
 
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Old 06-25-22, 07:21 AM
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Thank you Pjmax.

Can anyone recommend good replacements for this older unit? Looking for something newer looking and about the same size. Having a hard time even finding 120v thermostats to buy ...
 

Last edited by Lyphe 416; 06-25-22 at 07:59 AM.
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Old 06-25-22, 08:08 AM
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Follow up.
Is there any reason this would not act as a viable replacement?

https://www.mbtek.com/products/wifi-fan-coil-thermostat
 
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Old 06-25-22, 11:18 AM
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I'd need to look up the exact wiring but it looks like a viable replacement.
 
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Old 06-25-22, 12:21 PM
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Thanks Pete!
 
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Old 06-25-22, 01:55 PM
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1 ------> black --------> L1 (hot) ----------------> L
2 ------> white --------> L2 neutral -------------> N
3 ------> orange ------> heat valve ------------> HV
4 ------> yellow -------> cool valve -------------> CV
5 ------> gray ---------> Sw O/P - damper ----> ?
6 ------> violet --------> fan common -----------> cap off
7 ------> red -----------> fan/low -----------------> LO
8 ------> blue ---------> fan/medium ------------> MED
9 ------> brown -------> fan/high ----------------> HI

You would need to confirm that there is 120vAC between the purple wire and the white wire.
The fan common is used to keep the blower from running before the coil is hot or cold.
You will lose that. On a demand for heat or cool... the blower will start immediately.
I don't know if you have a damper. The wire may not be used.
 
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Old 07-05-22, 01:26 PM
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Do I need the extra 2 wires shown inside?

Hello all,

I'm installing a new 120v smart thermo ( MC6 FD1 ) to replace my old thermo ( Honeywell T6575D1009 ).

I've been able to deduce where to move most wires, but I'm left with 2 extras that I'm unsure of what to do with. The attached pictures show the old wires + new thermo + new thermo wiring chart.

The wires I don't have a home for from the old thermo are the grey #5 and purple #6 wires. I'm curious if I can just cap and ignore those when I hook up the new thermo.

Other wires seem to be self-explanatory. I see Live, neutral, heat, cool, fan1, fan2, fan3 on both units. But nothing for the grey or purple.

Any help appreciated and thank you!

P.




 
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Old 07-05-22, 03:54 PM
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I combined the two similar threads. I changed the title to better reflect the topic.
We pretty much went thru the wiring but you didn't answer the question I posted.
 
 

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