Honeywell IAQ wiring question


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Old 11-30-11, 08:24 AM
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Lightbulb Honeywell IAQ wiring question

Hi,

I purchased the
Honeywell YTHX9421R5010 Prestige IAQ Thermostat Kit (which includes the THX9421R5005 Thermostat, TM5421R1005 Equipment Interface Module, REM5000R1001 Portable Comfort Control and C7089R1013 Wireless Outdoor Sensor) and I have a few questions.

Note that I consider myself handy, but I never touched the wiring of a furnace. A local plumber is charging $300 to have this setup, so I am attempting to DYI.

I understand having the furnace and old thermostat information handy, but bear with me for a second since I won't be back at the house until Saturday. If I look 'in general' to the IAQ wiring guide, a few items are obvious:
- R/C will go to the new Honeywell Thermostat
- The furnace R/C will got to the IAQ R/C

My question is what to do with W/Y/G: do I simply run a new set of wires from my furnace W/Y/G to the IAQ W/Y/G connectors and leave all other cables in tact? The manual has them listed if I read correctly:
Furnace W/Y/G to IAQ W/Y/G AND Furnace C (Transformer). Is this correct or should this be hooked like this differently?

I have one furnace that I would like to control with this thermostat. Thank you so much for your initial input - I will provide more details when I have them. Just trying to get an idea of how complex this is.

Thank you.
 
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Old 11-30-11, 04:58 PM
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The EIM mounts on or near the furnace and you run new wires from the furnace connection board to the EIM according the the needed functions.

The EIM and the room thermostat are connected by either a two-wire or a four-wire cable ( I don't off hand remember which) and most often the original thermostat cable is used for this purpose. There are NO wires between the furnace and the room thermostat.
 
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Old 11-30-11, 05:32 PM
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Thanks for your answer! I have no problems at this point with the thermostat connection: I just want to know how the furnace connects to the IAQ: is it just connecting the extra W/Y/G wires from the furnace to the IAQ (next to the existing wires) or do I need to reroute any wires?
 
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Old 11-30-11, 06:54 PM
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The wires that originally went from the furnace connection panel to the thermostat are completely removed from the furnace.

New wires from the furnace are run to the EIM. These would include the R (red=power) the W (call for heat) and the C (common power return) for a heating only system. Add the G (green) wire for manual blower operation and the Y (yellow) for cooling. If you have multi-stage heating or cooling then you will have additional wires.

Any wires/cables going to an outside condensing unit (for cooling) will be left connected to the furnace connection panel.

I can't make it any simpler than this. I do suggest that you carefully read all the manuals that came with the system.
 
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Old 12-01-11, 06:39 AM
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Thanks again. I will investigate the wires and model numbers on Saturday and post any further questions. Seems pretty simple!
 
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Old 12-01-11, 09:30 AM
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If you have a simple 1-stage heat and 1-stage cool system this is fairly easy.

The EIM top R/C go the Prestige thermostat. This provides power to the thermostat.
The EIM lower R/C go to the furnace R/C. This provides power to the EIM.
The EIM W/Y/G go to the furnace Y/W/G.
To furnace R/C/Y goes to the AC condenser R/C/Y.

Make sure you have extra fuses for the furnace control board on hand before you start.

Programming the Prestige IAQ is so easy even a cave man could do it.
 
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Old 12-01-11, 10:35 AM
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Originally Posted by garya505 View Post
If you have a simple 1-stage heat and 1-stage cool system this is fairly easy.

The EIM top R/C go the Prestige thermostat. This provides power to the thermostat.
The EIM lower R/C go to the furnace R/C. This provides power to the EIM.
The EIM W/Y/G go to the furnace Y/W/G.
To furnace R/C/Y goes to the AC condenser R/C/Y.

Make sure you have extra fuses for the furnace control board on hand before you start.

Programming the Prestige IAQ is so easy even a cave man could do it.
Actually, I just have a steam heat furnace, so connectivity would be:

Disconnect the current thermostat.

The EIM top R/C go the Prestige thermostat. This provides power to the thermostat.
The EIM lower R/C go to the furnace R/C. This provides power to the EIM.
The EIM W/Y/G go to the furnace Y/W/G.

Correct?
 
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Old 12-01-11, 07:04 PM
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Originally Posted by realexm View Post
Actually, I just have a steam heat furnace, so connectivity would be:

Disconnect the current thermostat.

The EIM top R/C go the Prestige thermostat. This provides power to the thermostat.
The EIM lower R/C go to the furnace R/C. This provides power to the EIM.
The EIM W/Y/G go to the furnace Y/W/G.

Correct?
Steam Heat Furnace?

You have a steam heat boiler that supplies heat to the air handler for A/C??
 
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Old 12-02-11, 05:32 AM
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Originally Posted by Jay11J View Post
Steam Heat Furnace?

You have a steam heat boiler that supplies heat to the air handler for A/C??
I don't have air conditioning, no... Just a steam heat boiler
 
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Old 12-02-11, 08:36 AM
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Originally Posted by realexm View Post
I don't have air conditioning, no... Just a steam heat boiler
With no AC, you can leave Y totally disconnected. Y is the signal for cooling on a 1-stage cooling system and low cool on a 2-stage cooling system.

I had a house in Santa Fe like that a while ago, but it was hot water baseboard heat. Just a small bolier, no ducts at all.
 
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Old 12-02-11, 07:48 PM
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May I ask why you are going with such a high end t-stat for a basic steam heat?
 
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Old 12-02-11, 09:42 PM
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Originally Posted by Jay11J View Post
May I ask why you are going with such a high end t-stat for a basic steam heat?
You mean, why pay for a $200 stat when one for $30 to $40 would probably work fine on that system? I was just wondering that myself.
 
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Old 12-03-11, 04:30 AM
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Originally Posted by garya505 View Post
You mean, why pay for a $200 stat when one for $30 to $40 would probably work fine on that system? I was just wondering that myself.
Yeah, you could say that. ;-)

You'd need 3 wires between the EIM and boiler

R
W
C

The R can go onto any of the R's on the EIM since it has a jumper between all of them.
 
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Old 12-03-11, 07:44 AM
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Originally Posted by garya505 View Post
You mean, why pay for a $200 stat when one for $30 to $40 would probably work fine on that system? I was just wondering that myself.
Thanks all for your help. I will be at the house today. To answer your questions:
1. I actually also have second and third heating (baseboard heat) zones, which are (conveniently?) controlled by their own thermostats. We might want to consolidate all 3 thermostats into one.
2. We are considering getting CAC
3. The remote controlled heat (think: bedroom) is an awesome feature
4. The thermostat itself (touch screen) looks high end
5. The outside thermometer is also a nice bonus

So yes, I replaced the 'old' thermostats in the other two zones with $30 Honeywell's, but I wanted something feature proof for the main zone. And the remote control heat is hard to beat. We purchased this house 2 months ago and we're about ready to move in!
 

Last edited by realexm; 12-03-11 at 08:39 AM.
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Old 12-03-11, 05:53 PM
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I advise you not to combined all the t-stat into one.. Leave it on it's own zone for best comfort for that area the t-stat is in.


having it's on zone add comfort say you want it cooler in the bedroom, while it's warm in the living room, then at night, warm up the bedroom, and turn down the living room.

If you want digital t-stat on a zone, I'd go with FocusPro.
 
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Old 12-04-11, 06:59 AM
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Thanks again for the help. My furnace is a burnham sin5lnc-le2. The thermostat has 2to wires: red and white. In the control box these go to red and white. The other colors I see are yellow and blue. Any thoughts? I know red=power and white=heat, but I am trying to confirm what the common power return and manual blower cables are. Thanks again!
 
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Old 12-04-11, 07:09 AM
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If you have more than one stat, the wires may be going to the zone valve, then it goes to the boiler control.



I am guessing these wires are at the zone valve?

There is no blower, so you don't wire anything to G
 
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Old 12-04-11, 07:27 AM
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Originally Posted by Jay11J View Post
If you have more than one stat, the wires may be going to the zone valve, then it goes to the boiler control.



I am guessing these wires are at the zone valve?

There is no blower, so you don't wire anything to G
This furnace is wired for just one zone. So I guess my question which cable to use for C - Common power? Would that be the yellow or blue cable?

These cables are in a box where the thermostat is connected to the other cables. Not sure if that's called the zone valve. What color cable should C be?
 
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Old 12-04-11, 09:24 AM
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Looks like this might be a (class 2) transforrmer:
pri 120v 60hz wht blck
sec 24vac blue yellow

Then there is white and red (going to the old thermostat): an thoughts?
 
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Old 12-04-11, 08:46 PM
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I am confused, you said you have 2 other thermostat. Where is this going to?

just FYI, you do not have a furnace, it's a boiler. A furnace is a forced air system, boiler is a hot water or steam heating system.

Looking at the wire diagram, the yellow wire at the boiler is common.
 
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Old 12-05-11, 10:34 AM
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I am confused, you said you have 2 other thermostat. Where is this going to?
-> Steam heat for the main zone/house (t1)
-> Hot water baseboard heat for attic (t2) and den (t3)

With this in mind:
- pri 120v 60hz wht blck
- sec 24vac blue yellow

Current Setup:
To Thermostat: R and W
Near boiler: R, W, Y, Blue

New Setup:
To Thermostat: R, C (from IAQ)
To IAQ: R, W, Y (assuming Y is Common Ground)

Would that makes sense?
 
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Old 12-05-11, 08:03 PM
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Originally Posted by realexm View Post
-> Steam heat for the main zone/house (t1)
-> Hot water baseboard heat for attic (t2) and den (t3)
So you have two boilers?

Current Setup:
To Thermostat: R and W
Near boiler: R, W, Y, Blue
The old old R and W goes to R and W on the EIM. You are just adding another wire from C on the EIM to Yellow on the boiler.


Y (assuming Y is Common Ground)
No. Y is for A/C.
 
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Old 12-06-11, 06:32 AM
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Originally Posted by Jay11J View Post
So you have two boilers?


The old old R and W goes to R and W on the EIM. You are just adding another wire from C on the EIM to Yellow on the boiler.



No. Y is for A/C.
Correct, two boilers.

To clarify, this should be the setup correct?

Disconnect:
Boiler -> Old Thermostat
R -> R
W -> W

Remove old thermostat, install new thermostat and EIM

Connect
EIM (Thermostat Terminal) -> Thermostat
R -> R
C -> C

Boiler -> EIM :
R -> R
Y -> C
W -> W

Sorry for all the questions, but I want to make sure to do it right. I appreciate all the help.

On a side note, it looks like my setup can utilize the THM6000R1002 Honeywell Internet Interface Module "Gateway" which looks really cool. It will allow you to control the thermostat through the internet or cell phone. Does anyone has any experience with this?
 
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Old 12-06-11, 09:25 AM
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You got it.. I've never used the gateway, so i couldn't give you any feedback on it.
 
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Old 12-07-11, 03:38 PM
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Thanks all for your help. I installed everything today and it works well.... BUT... the EIM (and thus the thermostat) is resetting itself every 5 minutes or so (literally the power gets cut off). Any thoughts? The thermostat, remote control and outdoor sensor are all working properly.

I also checked double checked the wiring to make sure no cables are making contact. Any thoughts or could it be faulty EIM?
 
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Old 12-07-11, 08:31 PM
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Do you have a meter? Take a reading on R and C to see if you are losing power on it.
 
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Old 12-07-11, 10:06 PM
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Originally Posted by Jay11J View Post
Do you have a meter? Take a reading on R and C to see if you are losing power on it.
I consider myself handy - setting this up sounds simple but it's not as simple if you're not a professional but I don't have meter. Let's say for argument's sake that I did have meter and was losing power; what would that mean? From an amateur perspective with a technical background my guess would be either a EIM or Thermostat failure, but if you suspect something else... Please let me know!

By the way... You guys on this forum are great!
 
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Old 12-08-11, 03:11 PM
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We need to know if you are having steady power.. if we are, then you may have a bad stat or EIM.

If we are losing power, then we need to look else where.
 
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Old 12-08-11, 05:08 PM
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Originally Posted by Jay11J View Post
We need to know if you are having steady power.. if we are, thien you may have a bad stat or EIM.

If we are losing power, then we need to look else where.

I appreciate the feedback. I will be receiving a second EIM and a meter shortly. Living in NY winter is approaching. If steady power is an issue, then it will be a furnace and/or transformer issue right? What would be my options then?
 
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Old 12-08-11, 06:19 PM
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It could be the transformer issue on the boiler.

But we won't know till you do some testing.
 
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Old 12-08-11, 06:51 PM
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Originally Posted by Jay11J View Post
We need to know if you are having steady power.. if we are, then you may have a bad stat or EIM.

If we are losing power, then we need to look else where.

What would be the remedy?
 
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Old 12-08-11, 09:58 PM
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Originally Posted by realexm View Post
What would be the remedy?
I have been doing some more research. The whole system actually looks easy, with the 2 24VAC cables going to the EIM, which powers the thermostat. The white calls for heat and the thermostat communicates to the EIM wireless.

So there's not that much that can go wrong, besides a bad thermostat or EIM or a transformer issue (assuming all wires are correct). It also seems that transformers are really inexpensive if I have to replace them and I don't think the procedure itself looks like a big deal. A few transformer questions:
- If there is an issue with the transformer, does it only affect the thermostat? The old ther mostat was ancient; the boiler is from 1999. Not sure how old the transformer is
- Can I buy 'any' 120->24 VAC transformer to power the EIM or do I need to use/replace the boiler transformer?
- Any other 'transformer' thoughts or ideas where this issue might come from? I really want to keep the Prestige Set if possible...

I might be a DIY heating noob, but I'm trying to be a fast learner! Having an IT background helps
 
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Old 12-09-11, 05:27 AM
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The transformer may be a bit week, and can cause it to power to drop like we are seeing.

So take a reading between R and C at the EIM's system side when you see the stat go blank. If you are reading steady power there, then take a readying on the t-stat's side of the EIM.

Make sure the transformer has a higher VA rating.
 
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Old 12-09-11, 08:36 AM
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Originally Posted by Jay11J View Post
The transformer may be a bit week, and can cause it to power to drop like we are seeing.

So take a reading between R and C at the EIM's system side when you see the stat go blank. If you are reading steady power there, then take a readying on the t-stat's side of the EIM.

Make sure the transformer has a higher VA rating.
I will post the transformer information as soon as I have it. Would this be a tool that can do the reading?

http://www.amazon.com/gp/product/B000EVYGZA
 
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Old 12-09-11, 09:19 AM
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Originally Posted by realexm View Post
I will post the transformer information as soon as I have it. Would this be a tool that can do the reading?

Amazon.com: Equus 3320 Auto-Ranging Digital Multimeter: Automotive
You can use any multimeter that can measure AC voltage (most of them can). If the voltage looks OK, that I would also check the current draw, but that's a little tricky without blowing the fuse on the meter (trust me, I've done that at least once).
 
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Old 12-09-11, 04:12 PM
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Any meter can be used as long you can see the voltage reading on it.
 
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Old 12-18-11, 02:23 PM
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Hi All... Just a quick update that the new EIM fixed the issue. All set now - and I'm enjoying the remote control heat
 
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Old 12-18-11, 06:52 PM
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Glad to hear it's working!

Thanks for the update.
 
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Old 10-19-13, 05:22 PM
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Honeywell Prestige IAQ with EIM

I have recently installed a new heating system, and now I would like to add this Honeywell Prestige IAQ with EIM tstat's to my system. The system consists of a high efficient hot water boiler that serves radiant heat. The zones (2) are controlled by a Taco zone relay box. When the t stat calls for heat the relay activates a circulator pump and also sends signal to boiler to fire. I have used the 24 v output from the relay transformer to power EIM as well as the prestige stat. What terminals in the EIM do I land the r& rw from Taco relay box to activate circ. pump and start boiler?
 
 

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