A/C Pros in Highlands Ranch area?

Well . . . my AC suddenly died today. Has been working fine up to now. It's the original unit that came with the house (built around 1996). Ruud model # UAKA-048JAZ. I am starting to run through the basics that I can think of, but may need a pro to come take a look at it. Neither the unit not the fan is running when I mess with the thermostat. Same goes for the heat . . . I can turn thermostat to heat or cool and turn the fan on to manual and nothing happens.

- Main panel fuse was not tripped . . . tried tripping and turning back on and no luck
- Capacitor doesn't look blown . . .top isn't popped from what I can tell, but I am no electrical guy.
- May run up to the big box and try replacing the shutoff fuses??? Gues it's not that if the furnace doesn't run.
- Will also try cleaning off the fins on the unit. They are pretty clogged. Does not look iced up though.

Any thoughts . . . or know of anyone who speacializes in this who is in the area?

Check the fuse at the ssu

Look thru the sight glass on the furnace and see if it blinks a code.

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Originally Posted by Wulf202

Check the fuse at the ssu

Look thru the sight glass on the furnace and see if it blinks a code.

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IS that the round screw-in fuse next to the light switch on the furnace? It looks good to me, but I was going to run up and get a new one and try it just in case.

I don't see anything that flashes a code. It's an old furnace . . . like mid 90's. RUUD UGDG-12EARJR . . . so probably doesn't have the modern bells & whistles to show one??

Yes. That's the screw in fuse.

To be clear your furnace fan doesn't come on? I am referring to the furnace. Not the condenser.

The sight glass should be on the non louvered panel of the furnace. Otherwise pull this panel and hold or block the door switch and look at the main board for a few minutes while you've got it set to run. That panel should have a trouble code diagram on the back of it.

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Originally Posted by Wulf202

Yes. That's the screw in fuse.

To be clear your furnace fan doesn't come on? I am referring to the furnace. Not the condenser.

The sight glass should be on the non louvered panel of the furnace. Otherwise pull this panel and hold or block the door switch and look at the main board for a few minutes while you've got it set to run. That panel should have a trouble code diagram on the back of it.

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Correct . . . fan does not come on at all. If I set the termostat to heat or cool and if I set the fan to auto or on. None of that triggers anythign to happen and no air blows through the house vents (and nothiing happens at the furnace). Thermostat clicks and then nada. AC unit outside also does nothing.

I'll check again once I get off these conference calls. My only saving grace is that I have a portable AC in my office . . . so there's at least one cool room.

most likely causes at this point are a power faulire, board failure or a transformer failure.

Do you have a multimeter?

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Originally Posted by Wulf202

most likely causes at this point are a power faulire, board failure or a transformer failure.

Do you have a multimeter?

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I have a multimeter . . . but am totally remedial at using it. Willing to give anything a try though.

Furnace controls look like this. Not seeing anything that shows a code or lights or anything.

https://i.imgur.com/yF1ZkCa.jpg

1 verify power to the door switch on both sides when pushed. If no power move up to the SSU

2 verify power to the transformer. (black banded white square thingy with the yellow wires coming out top centerleft of pic) Hold door switch down

3 verify power output of transformer (yellow wires, voltages will be on the label) Hold door switch down.

4. look for indications of a trouble light, Small plastic window in the panel, LED present on the board, back of the panel has a troubleshooting code listing for number of blinks. Put the thermostat in heat mode and crank it up till it clicks to call for heating. Hold the door switch, if you have power to both sides of the door switch and the transformer AND have indications there should be a light and there is no light. Probably a bad board.

OK . . . I'll try to figure all those out. Appreciate the suggestions!

I have someone coming out on Fri if I can't figure this out before then. FIgured I better get on someone's schedule ASAP and I can always cancel if I get lucky. I replaced that fuse, btw . . . no change.

Well . . . I verified power from the panel to the switch with the fuse. And I have power to the door switch and power from the door switch to the board. I'll try the transformer check a little later--although not sure I know what to do for that exactly. Will try to follow your instructions with the wire identification.

Edit: Anything beyond what I checked to this point is probably well beyond my abilities to fix anyway, unfortunately.

Just thinking ahead to the worst case sceanrio . . . if this ends up being a costly repair, it might be worth our while to just punt on the 1990's furnace and upgrade? What are the Tier 1 furnaces and AC units these days (about 3200 sq foot house)?

Hoping it's not going to come down to that, but preparing for my typical luck.

OK . . . latest update. I pulled the 2 wires (black and white) from the bottom of the board that run up to the transformer and tested the "tabs" on the board. I have 120v there. I then put those back on and pulled the 2 yellow wires that run from the transformer back to the top area of the board and tested the connectors on the wires. I have zilch on those. That's assuming I did everything correctly--think I did but I am a total noob at using a multimeter. So . . . bad transformer at the minimum???

I did find the lights on the board. There are 2 green lights on the right hand side of the board sort of behind the big clump of wires coming on from the top. They don't light up at all when I turn on the heat and hold down the door switch.

Yes if you have 120v going to the transformer on the black and white you should have 24v on the yellow wires coming from the transformer You can also put the door back on and turn the furnace on. Pull the thermostat from the base plate and measure between the r and g terminal or the r and c terminal if a wire is hooked up to the c terminal and see what you have. I’m waiting for a -40 degree freezer to come down to temp so I’ll be on this for a while to help if need be. And just a good FYI he transformers they sell at Home Depot 90% of the time don’t have enough va to work

Also check to see if your control board has a fuse. It will be the kind your car has most likely. If you need a new transformer spend the extra to get a circuit breaker or put an inline fuse in with it, you’ll be happy when something shorts again and smokes the transformer. And if you do have a bad transformer that is possibly just the effect not the cause. In my experience something normally shorts out and toasts the transformer. Looking at a wire rubbing through or a contractor etc. in my opinion no matter what it is it’s not worth changing the system aside from maybe a compressor.

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Originally Posted by fitterjohn

Also check to see if your control board has a fuse. It will be the kind your car has most likely. If you need a new transformer spend the extra to get a circuit breaker or put an inline fuse in with it, you’ll be happy when something shorts again and smokes the transformer. And if you do have a bad transformer that is possibly just the effect not the cause. In my experience something normally shorts out and toasts the transformer. Looking at a wire rubbing through or a contractor etc. in my opinion no matter what it is it’s not worth changing the system aside from maybe a compressor.

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I'll look again, but I didn't see a fuse for the board when I was looking around earlier.

Definitely hoping it's just a component fix or two. The compressor has always run really strong and so has the furnace . . . so we'll see.

Sounds like a bad transformer. There's an ACE in aurora that stocks alot of hvac parts. As fitterjohn said, the HD ones are for doorbells and not suited for this application.

Sometimes transformers fry because of a short. check the wires in the brown sheathing to make sure they aren't cut. Also check by the condenser in case someone stepped on them or hit it with a weedeater etc

If you do change the transformer yourself. Set the thermostat to system off fan auto. Turn power on then change the fan to on. Then if it stays running turn the system to cool, if it stays running your good(unless you check heat operation, good techs always do��). If it goes off when you switch too cool then it’s most likely in your 2 wire going to the condensing unit or the contractor, in that case hopefully you put the inline fuse in or else it’s a second transformer. But fear not your compressor should be fine, compressors don’t take out transformers. Or at least I haven’t seen it yet.

Thanks again, guys . . . really appreciate the advice and walking me through some checks. I'll try to check the wires again for any apparent issues--didn't see anything that jumped out on initial look. With work the next couple days, I'm probably stuck til the tech comes out on Fri. I'll see if I can get away and maybe pick up a transformer but odds are low I can get away or that I can get one to me before Fri anyway. Not sure I even know how to take that thing out of there but will try to get a closer look.

At least I have a general idea at what might be wrong now. Sounds like it's a good idea to keep a spare transformer around like a spare hot surface ignitor?

Not a bad idea. I keep a transformer igniter, flame sensor, and a cap on hand for mine. But I also do it for a living for it’s just a walk to the van. If you lived near me I drop one off to you on the way home, but your a little out of the way. If you tackle it yourself it’s probably a 5/16 or 1/4 screws holding it in and it’s that simple If they tell you it’s going to be thousands consult on here

So, here’s the update. Had a guy come out who has done some work for us in the past (new water heater, some plumbing work) that we’ve been happy with. Ran through what I had found based on the advice here. He smiled and nodded his head and said “nice . . . that helps to know and probably saves some time.”

Transformer was for sure fried, so he said he likes to go with simple and works his way up from there. He grabbed a new transformer with an inline fuse . . . and it killed 2 fuses in a row. So . . . there’s a short “somewhere”. He narrowed it down to a short someplace on the wiring from the thermostat on the main floor down to the furnace. Problem is, we have a finished basement so a lot of that wiring is hidden god-knows-where. That thermostat has been in place for 10+ years, but he said the short wasn’t where he could see it and it could be pretty much anywhere. Said that wiring is not often very carefully put in place and it can rub on metal/pipes/etc and eventually short. The house is 20+ years old so it could have just hit that point on whatever weak spot it had.

He suspects it may have been a wire for a humidifier we don’t use. His concern was whether or not there were enough good wires to still use the old thermostat and have it work. If not, then he said it would be down to either trying to use a thermostat that ran on fewer wires, or if still shorting then run a new wire down (not fun) or just switch to a wireless thermostat—which the only one he had was $$$ and he said he’d rather not go there just yet unless he ran out of options. He ended up getting it wired back up and working with the old thermostat!!! At least for now, LOL. He said he had no way of guaranteeing that there wasn’t another short in the remaining wires that could go anytime—but said that, if it were him, he’d just let it run and call him if there’s another problem and worry about it then.

He told me the control board I had was notoriously bulletproof and that pretty much the only ones he’s ever replaced were from being submerged. So I guess that’s good to hear.
$260 all in to get up and running again. I may look for a good wireless thermostat just to keep on hand in case of emergency down the road to hedge my bets.

FWIW I'm in the process of installing a heat pump; it's arrived, still looking for a contractor to do the install. Part of that involved upgrading our thermostat to eek out the most performance. Lot's of hype in that market! Nest, Ecobee, blah, blah, blah. Wasted a lot of time sorting all that out.

Ended up going with a Honeywell Prestige IAQ system with Redlink and internet. What might interest you is it only requires 2 wires for the thermostat, all the rest is in a box by the HVAC. Plus all the reviews are pretty much stellar.

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Originally Posted by Ramsker

So, here’s the update. Had a guy come out who has done some work for us in the past (new water heater, some plumbing work) that we’ve been happy with. Ran through what I had found based on the advice here. He smiled and nodded his head and said “nice . . . that helps to know and probably saves some time.”

Transformer was for sure fried, so he said he likes to go with simple and works his way up from there. He grabbed a new transformer with an inline fuse . . . and it killed 2 fuses in a row. So . . . there’s a short “somewhere”. He narrowed it down to a short someplace on the wiring from the thermostat on the main floor down to the furnace. Problem is, we have a finished basement so a lot of that wiring is hidden god-knows-where. That thermostat has been in place for 10+ years, but he said the short wasn’t where he could see it and it could be pretty much anywhere. Said that wiring is not often very carefully put in place and it can rub on metal/pipes/etc and eventually short. The house is 20+ years old so it could have just hit that point on whatever weak spot it had.

He suspects it may have been a wire for a humidifier we don’t use. His concern was whether or not there were enough good wires to still use the old thermostat and have it work. If not, then he said it would be down to either trying to use a thermostat that ran on fewer wires, or if still shorting then run a new wire down (not fun) or just switch to a wireless thermostat—which the only one he had was $$$ and he said he’d rather not go there just yet unless he ran out of options. He ended up getting it wired back up and working with the old thermostat!!! At least for now, LOL. He said he had no way of guaranteeing that there wasn’t another short in the remaining wires that could go anytime—but said that, if it were him, he’d just let it run and call him if there’s another problem and worry about it then.

He told me the control board I had was notoriously bulletproof and that pretty much the only ones he’s ever replaced were from being submerged. So I guess that’s good to hear.
$260 all in to get up and running again. I may look for a good wireless thermostat just to keep on hand in case of emergency down the road to hedge my bets.

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I've dealt with many many shorts in low voltage.. I've never been able to NOT find them and/or isolate them and KNOW which wire is shorted either. Does your buddy have a multi-meter? Does he truly know electrical or just enough to get dangerous?

The only reason I ask is because in 14 years I've only had maybe 3-4 shorts in thermostat wiring going up through the walls to the thermostat. Not saying it doesn't happen, and you may have that issue but it's not exactly common.

I have however, had lots and lots of bad contactors cause this exact issue. He needs to either find the short with his meter to ground and/or isolate the AC low voltage circuit from the furnace low voltage.

Let me know what he finds.. Its kinda rare to have a true short in that wiring.

Ive seen a fair amount of shorts in the stat wire, but I work in the commercial field and people are always moving wiring around. Most common place for the short is right where the brown shielding it, people strip it off with strippers and cut through all the wires without realizing it causing a short between the wires.(hack install there is a right way and wrong way). But I agree never been able not to tell which wires are shorted, just a basic meter use. As far as thermostats my opinion is only Honeywell of a good quality, everything else is a gimmick. Maybe a Jci both are proven control makers, just no one stocks Jci thermostats.

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Originally Posted by bryjcom

I've dealt with many many shorts in low voltage.. I've never been able to NOT find them and/or isolate them and KNOW which wire is shorted either. Does your buddy have a multi-meter? Does he truly know electrical or just enough to get dangerous?

The only reason I ask is because in 14 years I've only had maybe 3-4 shorts in thermostat wiring going up through the walls to the thermostat. Not saying it doesn't happen, and you may have that issue but it's not exactly common.

I have however, had lots and lots of bad contactors cause this exact issue. He needs to either find the short with his meter to ground and/or isolate the AC low voltage circuit from the furnace low voltage.

Let me know what he finds.. Its kinda rare to have a true short in that wiring.

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He had a multi-meter. He's the owner of the company and they've been around awhile and seem to have a good rep . . . so I assume he knows what he's doing. It could be that my description of everything is more the problem in my word choice or order and since I'm not great at electrical and don't know that side or HVAC all that well. "Suspects" was maybe a poor word choice on my part. The short that was frying the transformer was in the wire he eliminated from what he was saying and when that was taken out of the equation everything was then working and not blowing the fuse. What he was saying was that he couldn't see or be sure where that short occurred in the line because it wasn't where it was visible . . . and that if there was a spot that somehow rubbed through to short that wire, that it could rub through another of the wires somewhere down the road and short there instead (or it may never happen or it could have been a nicked wire to begin with that finally made contact, etc). I'm assuming he checked other things while he was down there to see if there were any other obvious sources of a short but I wasn't watching him and probably wouldn't really know what I was looking at anyway.

I mean . . . I can only go on what I know (which is not much, but trying to learn) and what he's telling me and advising on what he'd do if it were his house.

When you say "bad contactors"--what would examples of that be? Is that just connectors on the board? I'm pretty remedial with electric and HVAC so I'm trying to get a better understanding of it all.

What he found is completely possible, I would just want to know exactly which wire in the bundle is doing it, but I’m pretty demanding if the people that work under me. And in a house it’s almost impossible to pull a new wire so a wireless is about the only option. THte contactor I’m referring to is on the condensing unit. It is kind of like a relay. It uses 24v on that one for the coil and pulls the contacts in to start the compressor and fan

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Originally Posted by fitterjohn

What he found is completely possible, I would just want to know exactly which wire in the bundle is doing it, but I’m pretty demanding if the people that work under me. And in a house it’s almost impossible to pull a new wire so a wireless is about the only option. THte contactor I’m referring to is on the condensing unit. It is kind of like a relay. It uses 24v on that one for the coil and pulls the contacts in to start the compressor and fan

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He actually said that it's fairly common (or maybe even most common?) for a shorting issue to be outside, so that matches with some other stuff he mentioned. He took a look out there and it seemed to all check out.

I really appreciate all the help and feedback here from everyone. I'm not the world's most handy guy, but I try to DIY stuff where I can and to learn along with way with repairs and home improvement . . . so it helps to put some additional pieces together along the way.

Here's a question on pulling a new wire.
The basement is finished, but it has a wood floor and a crawlspace underneath. The thermostat is pretty much above/near a little utility room in the basement (access panel for sump pump and crawlspace and a water softener). The furnace is on the other side of the basement, but the crawlspace is good sized and runs all the way over there. Could new thermostat wiring be run down under that floor and across/up to the furnace? Or does it need to be in/across the ceiling?

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Originally Posted by Ramsker

He actually said that it's fairly common (or maybe even most common?) for a shorting issue to be outside, so that matches with some other stuff he mentioned. He took a look out there and it seemed to all check out.

I really appreciate all the help and feedback here from everyone. I'm not the world's most handy guy, but I try to DIY stuff where I can and to learn along with way with repairs and home improvement . . . so it helps to put some additional pieces together along the way.

Here's a question on pulling a new wire.
The basement is finished, but it has a wood floor and a crawlspace underneath. The thermostat is pretty much above/near a little utility room in the basement (access panel for sump pump and crawlspace and a water softener). The furnace is on the other side of the basement, but the crawlspace is good sized and runs all the way over there. Could new thermostat wiring be run down under that floor and across/up to the furnace? Or does it need to be in/across the ceiling?

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Tape new wire to old and pull...............

I do what kazoo said but some a-hole always puts a staple in to hold it and keep that from happening. You can run a new wire any way you can get get it from a to b.

You can run the new wire around without much issue.

With finished basements you have the original tract installer and likely a different lowest bidder doing the basement finish. No telling where the wire is shorted. I've run several Stat runs because of suspected sheet rock screw hits years after the fact.

The reason there's such kickback about the diagnosis is that it's pretty easy to find out which wires are shorting though. Like less than 5 minutes with a multimeter would tell you which pairs or more have continuity.

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Originally Posted by Ramsker

Just thinking ahead to the worst case sceanrio . . . if this ends up being a costly repair, it might be worth our while to just punt on the 1990's furnace and upgrade? What are the Tier 1 furnaces and AC units these days (about 3200 sq foot house)?

Hoping it's not going to come down to that, but preparing for my typical luck.

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Contractors grade of Rheem 150K BTU Furnace 80% Efc and a 5 Ton Cond & Coil 13 seer w/ touch screen t-stat Installed to Code for $3500 +or - $100

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Originally Posted by Stu_Padaso

Contractors grade of Rheem 150K BTU Furnace 80% Efc and a 5 Ton Cond & Coil 13 seer w/ touch screen t-stat Installed to Code for $3500 +or - $100

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I would jump at that price if I needed one. Way cheaper than people are doing it in Fort Collins it seems like. Lol or maybe I just don’t want to do it so I tell people such a high price no one will take me up on it.

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Originally Posted by Stu_Padaso

Contractors grade of Rheem 150K BTU Furnace 80% Efc and a 5 Ton Cond & Coil 13 seer w/ touch screen t-stat Installed to Code for $3500 +or - $100

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Thats insanely low. In fact I question any person willing to do it for that Price. Especially 5 ton equipment and 150k btu furnace.

Very rarely are those size units ever used

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Originally Posted by Stu_Padaso

Contractors grade of Rheem 150K BTU Furnace 80% Efc and a 5 Ton Cond & Coil 13 seer w/ touch screen t-stat Installed to Code for $3500 +or - $100

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In fact if your willing to do it for that price then I will sub out all my work to you.

Please keep in mind that i have hardly no over head , and that is swap out meaning all work sheet metal , gas , electrical done to code but no permit , permits for new install or remodel is a must
for swap out stupid IMO , revenue gen for city that's it. Bryjcom i would welcome any and all sub work i will p/m you

Been away for the last several days so haven't been keeping up with my own thread. Appreciate all the continued responses and info!!!!!

Things are running like a top at the moment, so hopefully they continue to do so.