When my AC went out the tech told me it was the relay, however he didnt have the right model on the truck. I looked it up and saw it was $10 online, so rather than have him back out I told him I'd rather just install it myself. How hard could it be? Harder than I expected once I realized his "diagram" of how it was bypassed doesn't really line up with what is up there.

Here is the diagram he left:
[IMG][/IMG]

And here is what I see up there:

[IMG][/IMG]


Now, I'm familiar with electronics and wiring, but not AC's. It appears very easy to plug the relay in, but then presumably I need to hook the blower wire and the "yellow" wire to relay in order to allow it to turn the blower on and off.

The diagram shows a yellow wire with a cap, however as you can see in the picture, there does not appear to be a capped yellow wire. Thyen the diagram shows three wires capped, one labeled "blower", but its' not clear where this is either, as the only capped wire is a blue & red one.

So either the wires are elsewhere (like.. really far elsewhere, because I didn't see them in the area) or this diagram is wrong.

And second, once I locate these wires, where do they hook to the relay? All the contact appear to plug into the unit. On the other end it does appear that there is a place to hook two wires, but it is unclear how it would be done properly.

If I can provide anything else to help with this issue (more pictures of the whole work area, etc) then please let me know. I really don't want to have to pay $150 for a guy to stick a $10 relay in just because he did a weird bypass last time he was here and then didn't document it very well.

Thank you.

edit:
I have 2 AC Units and looked at the other one for hints and noticed that while the relay isn't the exact same type, it had no wires going to it. So maybe wires don't hook to the relay? But if thats the case, then they have to hook elsewhere, and I haven't figured that out yet....

 

None of your diagrams came through, so we have no idea what you're needing help with. See http://www.doityourself.com/forum/ai...st-photos.html for information on how to post photos and try posting the diagrams again.

 

Welcome to the forums.

A "91" style relay is two poles and both double throw which leaves you with eight terminals.

I'm not sure what you mean by plugging in the relay. Do you mean connecting the wires to the relay ?
That type of relay usually has slide connections.

I have a feeling we're going to need the make and model of your air handler to help you.
(along with the pictures)

 

Bob14525 - The pictures are showing up just fine for me? I am quite familiar with posting pics to forums as I an mod of several forums myself. Maybe the host I chose for my files is blocked on your computer?

PJmax - When I say it appears to plug in very easily, I mean that if you look at the picture of my unit/wiring you can see a blank spot with 8 slots that line up with the 8 terminals on the relay.... so I assumed I just plugged the 8 terminals into the 8 slots to install it. I wasn't real sure where the wires themselves hook up to though.

I'll take more pictures of the entire unit tomorrow and post them. Can you not see the 2 pics on this post either?

If not, I don't understand why they appear for me (even after leaving the site and returning in a new tab which means they aren't cached).

Thanks to both of you for your replies.

 

There is something in the file name the board doesn't like. They are now on my photobucket site. I could get to your storage site but could not get the board to load them.

Anyway... here are the pics. Left me look at them and comment.

On edit.... your tech is none to helpful and the splices are under the relay socket. Remove that relay cover from the 4" box.

 

There should be no wires directly connected to the relay. All your wires SHOULD be connected to the backside of the relay plug (inside the junction box). You simply need to plug the relay in. If it's not the same relay type, then you will have to confirm proper wiring orientation before restoring power.

 

Bob.... his tech bypassed the relay so that the blower was working.... probably for heat only. The splices behind the relay will have to be remade.

 

Anthony, I can now see the pictures (PJmax, thanks for "fixing" the pictures). I think I understand now what the relay is doing. It's taking the 24VAC from the thermostat (when the stat calls for heat/cooling) as the control signal and energizing the blower motor. I don't know what your wiring looks like (as PJmax stated, it's hidden), however I can think of a simple way to connect it up to the thermostat wiring using a couple of diodes. It appears that there is a socket for the relay, so the wiring would be connected to the socket (behind the mounting plate), again as PJmax mentioned.

 

PJmax - I really appreciate you fixing the pictures.

Also - the blower runs at all times, for heat or for cooling. Essentially it is always blowing room temp air, but if the AC kicks on it starts blowing cool air and when the furnace kicks on it blows hot air.

Bob - The relay does look like it would directly plug in, o that part is easy. As you have both figured out, the issue is with the wires that were bypassed.

I will remove the cover, take a picture and get it posted as soon as I get home. I didn't realize the wires he had messed with were behind there, but that would explain why I couldn't locate the wires he had marked on the diagram.

Thank you both again.

 

Ok, I used photobucket this time... hopefully it works better

Here is the unit type


Opening the panel I notice this yellow wire not connected to anything and just sort of stuffed in there:


Here is the wiring to the back of the relay plug:


And here is an overall view of all the wires. I tried to split it apart enough to allow all of the wires to be viewed:


As you can see, the relay plug is lacking wires at terminal 3 and 5. The yellow wire that is not connected to anything is possibly the yellow wire referenced on the sheet of paper the tech left with me?

Let me know if I need to take more pics of the wires. I notice some of hem towards the back are still difficult to see properly (or at least to follow where they are going in these pictures).

 

I couldn't find any wiring information on that specific Armstrong model, however I did find some info on a couple of similar but different models. Both had the same wiring diagram. Here's what I found. It may or may not be similar to your model.

http://i1288.photobucket.com/albums/...psaxutlzg0.jpg

 

Anthony,
There should be a wiring diagram glued to the inside of the door on the blower compartment.
If that is the same fan/limit control Armstrong used on thier oil fired furnaces, those two yellow wires apply a current to the fan/limit on a call for heat. The purpose is to bring the fan on sooner than it would normally come on due to heat from the flame. Since you run your fan all the time, it's a moot point. You can leave them disconnected.

 

Ahh yes, thank you. I should probably learn how to read

 

I will look for the wiring diagram and post a picture when I find it. However I'll have to locate the blower to do this.

In regards to the second point, I don't want to run my fan all of the time. That's the entire point of installing this relay and hooking the wires back up the way they were before my tech bypassed the relay.

That fan has been blowing nonstop for months and apart from the waste of energy, it is loud and somewhat obnoxious. A tech did this last august I believe. He did it for the summer months, so while I keep hearing the mention of heat, I know that this was done to fix the AC. He bypassed the relay because the house was over 100 degrees and the cool air wasn't blowing into the home. So by bypassing the relay, the blower came on and started cooling the home down. So this is most definitely not just for heat.

So leaving the wire disconnected doesn't seem like a great idea if I want to get things back to the way they used to be...?

 

No problem.

With that relay.... there are two things happening. When it is not energized it allows the fan/limit control in that gray box to control the fan, based on heat, for the furnace only.

A/C or FAN ON mode activates the relay which turns the blower on, usually on high, and disables the fan/limit switch.

This is done so that the fan/limit speed setting, which is usually medium, can't be activated the same time as the high speed A/C mode.

We'll get your wiring straightened out... I'm looking now.

 

I think when I opened the box I killed the blower. It is no longer running, so when I got home today the house had heated up quite fast. That errant yellow wire was likely hooked to something before, and was likely just barely hooked in.

Or, if that wasn't it, then something else came loose. Just like when the relay died, I can hear the system running and the condenser is on full blast, but no air is coming through the vents.

 

On your air handler..... there should be a service door. On the back of that service door is the wiring diagram.

 

Where do those 2 yellow wires originate from? What is the model # on that Honeywell fan control?
terminals 1-2 N/C. 4-6 N/O on the relay, the 2 blue wires from the relay base are the coil feed controlled by the Tstat.
Geo

 

I believe those two yellow wires are from the limit part of the fan/limit switch.

I've been looking at the wiring. It looks the heavy orange wire is connected to the black wires with a red wire nut. Remove that orange wire from that connection and reconnect it to the black wire with the yellow wire nut.

 

The bottom pic shows both yellow wires connected to fan center,when was it removed,or put on there?
Geo