My heat and AC seem to be confused.


I have a Rheem AC and furnace, the AC worked great this summer, and my heat was working until today. I turned the heater on, and the AC unit outside came on and the air was freezing cold. I turned it off and back on and nothing comes on. I turned the t-stat to cool and set a temp to the displayed tem on the T-stat, and the heater comes on. Switched the t-stat to off, and took almost 20 minutes before anything turned off. Tried the same steps again, and only AC comes on in either heat or cool setting. I have no clue about electronics, or hvac technology, so I do not know anything more than what the t-stat says.
I really appreciate any advice that can be given. Thanks much.

Is your heat electric or gas? Model number of furnace and thermostat would help

The furnace is Rheem Criterion2, AC unit is Rheem classic RAMB 030JAZ, thermostat is a white one with no numbers on it, it has programmable feature, and I can open the door and pull off the panel that has the display and buttons. I know nothing about these things, sorry for my ignorance.

Sorry, it is a gas furnace

Yeah, sorry, I can't really put my finger on what's causing it.

A good informative source I use is this handyman site, which has a section on AC units, where you'll find a text-link ad that gives up to four free estimates prepared fast by local AC contractors in your area (scroll down to the middle somewhat to see the text-link towards the middle of the page):

Central Air Conditioners ~ Your Handyman Zone :: Hammer it Out in the Zone ~ Home Improvement Zone...Cooling and Ventilation Systems Category (http://yourhandymanzone.com/Your_Handyman_Zone_How_To_Pages_Home_Improvement_Z one_Cooling_Ventilation_Systems_Central_Air_Condit ioning.htm)

Click on the "Find A/C Contractors. Get Up to 4 Quotes Now...Free" text link. Since really everyone is clueless on here, and you can't go without heat, much less get a new AC unit, your best bet is to get an AC contractor out there to service your unit, and the best way to avoid getting ripped off is to get concrete estimates.

Good luck!

Yes, it does sound confusing.

Thermostats do have what's called "anti-short cycling delays". What this means is, that the outside unit cannot come on unless it has been off for a certain amount of time. That delay is between 2 and 5 minutes.

Isolating the faulty component will be tough.

Well what I meant is that when I turn it off, it takes almost 20 minutes before the AC unit outside actually stops making noise and blowing air in the house, the AC comes on right away when I turn on the heat or air. Also it is hard for me to find a model number for my furnace, as it is in my crawlspace in my ceiling. I am going up there again tomorrow, where would I find status lights if this unit has them?

Another question, I have noticed that when I turn on the heat, the AC unit outside kicks on, this did not used to happen.

It's almost like its acting as a heat pump or dual fuel system.

It would be interesting to know what terminal designations the thermostat has. i.e. Does it have an O or B? ---> Heat pump

What could be happening is that a relay is sticking somewhere.

The one that seems likely is the one outside. Pull the disconnect outside. This usually means opening the box on the wall and turning the pull out switch upside down. If that's not there, then kill the breaker for just the outside unit. You'll likely have heat.

At this point, I THINK the problem is outside.

First time the ac came on when I turned on the heat I immediately turned the AC off at the breaker, nothing came on, stopped messing with it, and the air started blowing, but not hot or cold, just felt like it was pushing room temperature air through the house. I tired again about 45 minutes later with the breaker back on, and the only consistance is that no matter if I have the thermostat on heat, cool, or auto, the AC comes on.

Sounds like a really wacky thermostat, or damaged control wire, most likely somewhere between the furnace and thermostat. Trace the visible/exposed section of the wire looking for pinches, breaks, or melted areas.

Yellow, white and red look burnt on the tstat end, where they screw in.

But the green in the middle is not burnt at all

You said gas, so it should not have O or B terminals.

R -
W - Heat
Y - Cool
G - Fan

Mark the tstat wires, take them off completely, and make the connections with power off and try the following:


R to G; Only the fan should come on
R to Y; Only the outside unit should come on
R to W; the fan and heater should come on

(C) if present, is optional (tape up)

The terminals should not be burnt. If it passes the above tests, then the tstat is bad.

DO you have any additional terminals besides R,G,Y,W, optional C.

R can be R&Rc or Rc/Rh

If you haven't figured it out, R (Red), W (White), Y (Yellow), G (Green)

C - often blue

There are spots for rc/rh but no wires. The tstat face comes off and the wires unscrew from speaker-like connectors, they are burnt on the bare wire there also, I have not tested your above post yet, but the AC outside comes on no matter heat/cool.fan setting. I will try what you have posted now.

http://www.kodinfo.com/mith/tstat.jpg

Here is what I mean, because I don't think I explained it well

They do look burned... has this house been ablaze before? Perhaps the wire is melted somewhere. Try pulling the wire out of the hole in the wall.

No, this house has never been on fire. And a little further back, about 3/4 inch at most the wire is in a casing, kind of like a phone wire, or a cat-5 cable. The only damage to the wire is in the picture, fine at the AC outside, and fine at the furnace in the ceiling.

I'm wondering if the black could be leftover adhesive from electrical tape used in pulling the wires.

There are the same terminals on the other side of the picture above, can these be used instead? I will go get a picture because I think they may be labeled slightly different

http://www.kodinfo.com/mith/tstat2

Other terminals

http://www.kodinfo.com/mith/tstat3

Whole tstat

http://www.kodinfo.com/mith/tstat2.jpg

Other side

http://www.kodinfo.com/mith/tstat3.jpg

Whole thing

And yeah you are right, it is some gummy adhesive leftover residue, if I scratch the wire with my fingernail, it comes clean.

You said gas, so it should not have O or B terminals.

R -
W - Heat
Y - Cool
G - Fan

Mark the tstat wires, take them off completely, and make the connections with power off and try the following:


R to G; Only the fan should come on
R to Y; Only the outside unit should come on
R to W; the fan and heater should come on

(C) if present, is optional (tape up)

The terminals should not be burnt. If it passes the above tests, then the tstat is bad.

DO you have any additional terminals besides R,G,Y,W, optional C.

R can be R&Rc or Rc/Rh

If you haven't figured it out, R (Red), W (White), Y (Yellow), G (Green)

C - often blue

Done exactly as you posted, everything came on properly, and normally, so now I just need to replace the tstat?

Does it matter what kind of tstat I buy?

No. It looks like you have a common wire the so you can install just about any kind you like.

I fixed the above post, so it makes sense.

Furnace Filters, Air Conditioner Filters, Air Quality - iaqsource (http://www.IAQsource.com) has a nicely arranged website.

You need a thermostat that will support a 1 stage heat/1 stage cool conventional system. Some stats are configurable, some are not.

Honeywell's Focus Pro series is "homeowner friendly"
The "Vision Pro" has lots of options and is contractor friendly.

Stay away from the Hunter brand.

I'd take a look at some of the instructions to figure out which might be best.

Now is the time to get a programmable stat. One option that I find that I'm using a lot is the override for a certain length of time and, of course, programmability. My system "burps" in the winter just to get the temperature up, so it's easier to get out of bed.

You want a stat that uses batteries for backup purposes only.

White Rodgers and Honeywell are solid brands.

The only issue you should run into is the addition of Rc/Rh. More than 1 stage stats can usually be reduced to 1 by programming.