Question about Ruud UBHC Air Conditioner

1 Answer

Thermostats being replaced often

One customer has had 5 new stats on 2 different systems. What should I look for? Transformer or house voltage issues or grounding issues?

Posted by on

1 Answer

I have repaired A/C commercial and in dustrial for 40+ years. ( ot of ten times replacing one item as a t-stat 5 times pretty much proves it is not the thermostat. The VA rating on your transformer has to ne able to carry the total load of your circritry.

Yes, I have als seen cases wher a intermitent short occurs in the thermostat cable that has up to 6 different wires in it.

Also "Heat anticipators" in all t-stats (Unless they are automatically controlled) need to be set properly.

You need a AMP reading meter with a Volatage and Resdistence Meter.

I suggest calling a professional. ONE WHO IS LICENSED TO WORK ON THE MODEL OF AIR HANDLER AND CONDENSER YOU HAVE. THE T-STAT MUST BE WIRED CORRECTLY TO THAT SYSTEM. TRANE, CARRIER, RUUD, GOODMAN, ALL ARE DIFFERENT IN COLOR CODES FOR WIRING.

I had one job wher a painter had nailed through the t-stat wire inside the wall and caused a short between the Red (Hot wire) and the ground wire ( in this case it was the blue wire) Depending on the t-stat ... There ar up to eight terminals that need to be i9dentified and then properly wired.

Heat pumps use at least 5-6.

5 t-stats failing is gettin close to $500 of repairs if not more.

Posted on Feb 09, 2008

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

1 Answer

My unit is not putting out power to the thermostat. It's a heat pump with aux heater. Voltage tested between R and AUX/W2 posts show no Amps. What could cause this?


You have to go to your indoor unit its called a airhandler check high voltage going to unit should be 240volts .if you have 240volts look to see if there is a fuse either on the board or in line it will look like a car fuse 3amp or 5 amp check if fuse is blown but before checking make sure you pull disconnect so you dont have any high voltage going to unit. If fuse is blown get same exact fuse auto parts store will have them replsce put stab back in diconnect unit should run .if there is no fuse in airhandler keep high voltage on go to transformer and check for low voltage comeing out of transformer .NO 24 volts comeing out .replace transformer.if you have 24 volts comeing out of transformer check low voltage wireing thermostat wireing one goes to thermostat and other goes to out door heatpump usealy Brown in color and will have 8 small different colors wires inside brown jacket. Check for 24volts between red wire and common should be blue color if it is color coded. If no voltage there is a break in red or common wire.or sometimes just wirenuts need to be retightin.also when checking for low voltage one leed must be on common and other lead goes to red.also with high voltage off take face off thermostat carefully make sure all connections are TIGHTEN. This will also so you witchcolor wire is common it will be connected to C terminal hope this helps.note must have 24volts red and common or t-stat will not light up.hope this helps

Feb 26, 2015 | Air Conditioners

1 Answer

Where is the low voltage 24 vac transformer located?


The transformer is located in the furnace. You might want to check to make sure the furnace door is on correctly brcause theres a swich that will open for safety . Also some have a fuse on the solid state board.

May 26, 2014 | Rheem RASL024JEC-RHPNHM2421JC 2 Ton 18.50...

1 Answer

I replaced an old mercury T-stat (York with model number 2TH11704024) installed a new T-stat (RTH6350). The wires that I I have are O (orange), G (green), Y (yellow), T (gray but not used in new T-stat),...


Did you shut the power off to the air handler/furnace...... before you installed the new thermostat??? You may have shorted out the transformer or blown the transformer fuse...... If you try to put the Fan switch on the stat to Fan ON does the fan come on ..... if it does the transformer is OK.. On the new thermostat did you program it to tell it that you had a heat pump system ???? Looks like you had it wired right. Here is a pdf manual for a RTH6350 http://customer.honeywell.com/techlit/pdf/PackedLit/69-2416ES.pdf

Its on page 13 Advance setup for tell the new stat that you have a heat pump....There is also a Honey well Hot line on page 2 Hope this helps.

May 01, 2011 | Air Conditioners

1 Answer

I have no voltage to my thermostat


Hi, I am not positive the control voltage to your thermostat will be on a RV a/c, most homes are 24 volts. I know yours would be less. If you have a 2-wire stat and this a/c is not working, take the two thermostat wires a touch and hold them together. Don't worry as this is safe and will not shock you. If the unit comes on and runs, you do have voltage there but the meter may be set wrong. If nothing happens, then you need to find the breaker for this unit to see if it as tripped. Reset it anyway. If still no power, you will need to find the transformer for this unit and check for power to it which will be high voltage/primary and power out which is the secondary low voltage which controls all low voltage controls such as the stat. If you have a wiring diagram on the condenser up top or most RV have a large book that tells you about your coache. If you have a diagram look for the thermostat as it will be labeled in the legend as a T with a circle around it or it may say stat. Follow to see where it gos from there, to the transformer or what and let me know. If the unit does fire when you jump out the stat wires, you will have to replace the stat. Please keep me posted on this. You may have a blown fuse up top cutting off power to the transformer also. You can ohm them out also. Keep me posted so we can solve this.
Sincerely,
Shastalaker7

May 11, 2010 | Dometic Rooftop RV Air Conditioner

1 Answer

Thermostat wires dead


If you have a split system (an air handler that blows air into your house and an outdoor unit that has the compressor and condenser coil/fan), then you should look in the electrical compartment of your indoor unit and see if you can locate a low voltage fuse. This is usually located on the control board or between the transformer and "R". Make sure you shut off the power to your indoor unit first as they will still be 240volts available there. If the fuse is blown, replace it and reinstall your thermostat. Turn the power back on. If the thermostat is wired properly with no damaged wires in the process, the system should work fine.
If there is NO fuse, then check the low voltage side of your transformer using a Voltmeter. You will have to have the power on to perform this test. Be very careful. On one side of the transformer, you will read 240volts. The other side should read 24 volts. If there is no voltage on the 24volt side, you blew the transformer and will need to replace it.
Check these items first. If you need further assistance, let us know and we will dig a lil' deeper. :-)
24%20v%20transformer.jpgpicture of a typical transformer.

The low voltage fuse could be a glass cartridge fuse (systems typically older than 15 - 20 years old). Newer systems use the same style fuses that are used in your truck or car (ATC type).

Apr 08, 2010 | Hunter 30124 Air Conditioner

1 Answer

Have a Ruud AC unit the problem I have after installing a new condenser fan motor when I throw the circuit breaker the unit will not turn on but when I push the contacts on the contactor in manualy the fan...


The contactor engages from low voltage power from the thermostat as does the outside condensing unit. You may have blown the low voltage transformer or have a loose thermostat wire. Check line voltage(220 volts) to the transformer. Check load voltage(24 volts) from the transformer. If no voltage out,replace the transformer. If you have voltage out(24) check the thermostat wires and the thermostat. If you have a digital thermostat there is a 5 minute delay in the thermostat after power is restored before it activates.

Oct 08, 2009 | Ruud Central System Air Conditioner

1 Answer

Have Amana furnace model GUIB070A30 condenser model RCA24A2A. Replaced a battery and since then neither the air conditioner or furnace will come on. Any ideas? Is there a reset button? Where is it to try?


sounds like you shorted out the t-stat or transformer, low voltage is real sensitive on this type of unit and the only reset button would be on the tstat depending on which type and model thermostat look in owners manual on tstat reset if you cant find take stat off wall and twist red , green, and yellow wires together and if the whole system comes on replace stat if it doesnt the transformer in a/h went bad

Sep 28, 2009 | Air Conditioners

2 Answers

No voltage to thermostat.none to condenser vltage.main voltage to con.ison.


Check for proper voltage to the unit , (generally 110VAC) check the transformer secondary for approx 24 volts. Verify the door switch is operating properly and that the door switch engages when the cover is put back on. if all of this proves good then check the wirtes going to the thermosta and the condenser

Jul 12, 2009 | Air Conditioners

1 Answer

Carrier heat pump


fuse is usually a small resetable breaker on the side of the transformer, or a traditional screwin fuse with a plastic cap on one end that is a specialty fuse and is available at most motor shops or elec supply houses. or its a auto type plug in fuse on the circuit board usually 5 amps or three amps. first turn the fan switch on the stat from auto to on. does fan run? if it does you have high and low voltage and your wired wrong. if it is in the stat you are usually looking at red connects to red . yellow to yellow, green to green , orange to orange, white usually to white, that leaves a common power wire to operate the stat, usually connected to the common term on the new stat . this can be any color and is necessary for the new stat to think and work, if it has batteries it will have a display but it needs a red and a common to think and work. this wire can be any color and if your old stat had no common which a lot didnt then youll have to add one. carrier also has a emergency heat strip wire sometimes labeled x2 etc. you can usually jump white over to x2 to perform function if needed. good luck.

Oct 22, 2008 | Air Conditioners

Not finding what you are looking for?
Ruud UBHC Air Conditioner Logo

110 people viewed this question

Ask a Question

Usually answered in minutes!

Top Ruud Air Conditioners Experts

Lawrence Oravetz

Level 3 Expert

7686 Answers

Stephen

Level 2 Expert

188 Answers

MightyMikeJr

Level 3 Expert

347 Answers

Are you a Ruud Air Conditioner Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...