Indoor and outdoor unit not coming on.

OK so i have a very old unit outside and in (outdoor)rahe-030jas and (indoor furnace) rgde-06elaes. I am an HVAC newbie so bare with me on some of the technical terms.

I'll tell you what happened before i tell you what i've tried to do.

I got home late one night and my girlfriend woke up and told me the ac wasn't working, she said it was working fine and all of the sudden it shut itself off and turns itself on about 5 times within a minute or two and then stopped working.

Now when i turn thermostat to cool i hear the thermostat click like its trying to kick on the unit but nothing happens, which makes me think its not the thermostat. The t-stat Doesn't work on Heat/Cool or Auto/On on either setting.

Tested methods

1. I've looked at my float switch and it doesn't have any moisture in the switch itself, but it almost looks like there is dirt kind of close to where the tube comes out of the furnace, but the drain and switch itself look clear.

2. I've gone out to the back and flipped my breakers with no luck.

3.i replaced the capacitor on my blower motor about 2-3 months ago so i wouldn't think its that, plus my fan doesn't even sound like its trying to come on. (Same with outdoor unit)

4.Checked for ice on any of the lines outside.

5.I couldn't find any kind of reset switch on my outdoor unit i'm assuming because its so old.

6. I also have taken a multimeter to the thermostat and circuit board (on the furnace) and get NO READING which is where i'm thinking the problem lies, I just have no idea were to go next from here. I have a few things hooked up to this breaker that DO work so i'm a bit baffled.

Could a faulty float switch cause me to get no power to the circuit board?

 

With the thermostat set to OFF, take your multimeter and measure the voltage between the R and Y terminals. Ideally, you should measure 24VAC. If you read 0V, you've likely lost your 24VAC which comes from a transformer usually located in or near your furnace. You may have a fuse in the 24VAC line coming from the transformer. If you find a fuse, check it and see if it's open.

You might want to take some pictures of your furnace, particularly if you don't have 24VAC and you can't find the transformer that supplies the voltage.

 

I used the multi meter and went from the red wire to the green, yellow, and white wires to see if any of them put out any voltage and neither did on either setting Heat/Auto, Heat/On, Cool/Auto, Cool/On, and off . I did the same for the circuit board on each setting.here are some pictures of my furnace. its a little hard to see the circuit board through the rats nest in there, but i took the best pictures i could, if theres something you want to see specifically im sure i can get a pic...

 

Check for primary and secondary voltage.
When was the last time the heat exchanger was checked on that thing? I see lots of rust.

 

In your last picture, it appears that the 24V transformer is on the left side, above the circuit board, and to the left of the Robert Shaw ignition control. While I can't say for sure (hard to see in the pictures) it appears that the transformer primary (input) is on the right side (yellow & blue wires) in the picture. The secondary (24VAC) would be on the left side (assuming I'm correctly interpreting the picture).

There should be 120VAC on the primary of the transformer, and 24VAC on the secondary (output). Very carefully check for voltage at the primary and secondary of the transformer. Typically, the secondary wires from the transformer will go to the R terminal of the thermostat and the other wire is usually connected to the furnace chassis.

 

@Bob14525 could you edit my picture and put a circle on what your talking about...im not quite understanding what your talking about.

 

@roughneck77 i moved in last year so i haven't really done any maintenance to it, this is my first house and my first time dealing with any of this stuff, so im pretty oblivious. i can follow instructions and have done a few things around the house that...when getting into it i thought i was over my head, but after a bit of research found out it wasnt that bad...i replaced my blower motor on my hvac about 2 months ago with no issues, so im not super scared to get into this lol.

 

I've circled the transformer.

 

Sorry Bob i was busy doing other things, but i took the transformer off just to see what i could see. From the angle it was on there i couldn't see any exposed wires to test it with my multi meter but here is the information i can give you.
The transformer has a plastic film over the wires (where they would be exposed) on each side. There are 3 wires on the left. (white, red, and orange)
The white wire is joined to a black wire with a wire nut, that goes to N5 on the circuit board.
The orange and red wires aren't connected to anything, they just have a wire nut on the ends.

The wires on the right side are blue and yellow. The yellow wire is joined to a wire nut to another yellow wire that goes to X on the circuit board.
The blue wire is joined to a different yellow wire with a wire nut that goes to C on the circuit board.

Both yellow wires are connected right next to each other on the circuit board.

Sorry i know the grammar is all messed up but I would have taken pictures if the wires weren't such a mess, i just figured laying it out that way would be a little bit easier to read....but maybe a bit more frustrating if your a grammar **** lol.

Im also going to provide pictures with the wires drawn out so its a bit easier to understand. The gray line is the black wire. A Black line was hard to see on the picture.

Green O's are were wire nuts connect something, Purple X's are were they lead to nothing.

 

That may not be the 24VAC transformer since it has 3 wires on one side, two of which are unused. I was able to find a wiring diagram doing a Google search on your furnace model number (link below). Is your furnace a Rheem brand? The wiring diagram (if it truly is for your model) shows a slow blow fuse in the 24VAC line.

https://resource.gemaire.com/is/cont...wd.pdf?fmt=pdf

 

think thats a bit off, but i do have the diagram right here, it was on the other side of the circuit board cover

 

Thanks for posting the wiring diagram. The diagram does show a fuse. It's in the primary circuit of the transformer. The fuse is near the top of the diagram near the right side.

 

I'm sorry but i have no idea what i'm looking at here...ive looked all over the circuit board for a fuse, and all over the furnace. I've even gone up into the attic to see if i could find some sort of fuse box, but cant find anything up there.
It also shows a fuse in the bottom left of the diagram...is that the same fuse?

 

It may have been removed at some time.
Start with testing the power feed and the primary side of the transformer. Then if all is well move onto the secondary side.
Your furnace looks in need of some tlc. I’d be very curious of the condition of the heat exchanger given that everything visible is very rusty.
Based on visuals alone your likely looking at a new furnace in the near future.

 

well is the black thing the transformer? ill take a picture of the top of it and send it to you guys to confirm, but if it is where do i put my probes? theres a red orange and white wire coming from the left side, two of which are unused (orange and red) the white wire connects to a black wire into the circuit board, the right side has a yellow and a blue wire, the blue wire connects to a yellow wire with a wire nut and the yellow wire connects to another yellow wire into the circuit board.

 

OK figured it out, apparently there was a black wire that i didn't see coming out of the left side of the transformer.I found that out quickly after disconnecting all the wires i could see and trying to take it out of the control panel... I tested that wire with the white wire and get a 120v in but i don't get the 24v out the right side (blue and yellow). So i'm going to go ahead and replace the transformer and check out the contactor and see if that also needs to be replaced. From a lot of the videos I've been watching a problem with the contactor is most likely what shorted it out in the first place. Anywhere else i should look for a short? I don't want to buy both of those parts if it ends up being something else that may have shorted it out and have it short out all over again.

 

Buy a transformer with internal protection.

 

OK GUYS IM MAKING PROGRESS!!!! I got the blower and the condenser to come on after replacing the transformer and the contactor. Now the only way i can get it to come on is if i hold the Temp down button on the thermostat. Sound like i need a new thermostat?

 

Yup definitely the thermostat, i hooked up all the AC wires going to the thermostat and it kicked right on and has been running for about 10 minutes now. Bout to run to lowes and pick a new one up right now, THANK YOU SO MUCH BOB AND ROUGHNECK!!!!!!!!!!!!!!!!

 

well the new thermostat is trash, put batteries in couldn't get a display, then connected the wires thinking maybe it was just missing that....nope, gotta go to lowes again tomorrow and swap this one out for another.... >.>
i atleast have cool air at the moment because i connected my ac wires.