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I'm not getting any low voltage at the t-stat.

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Make sure that the transformer has power on the primary side then check the secondary side for low voltage. If you have power on the primary and none on the secondary then replace the transformer.

Posted on Sep 05, 2010


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1 Answer

Have two Broan exhaust fans that I want to wire to a programable hvac themostat.I'm told that I need a relay and not sure how they are wired. The fans draw 1.23 amps each and looks like they have

are you sure that your not looking at motor capacitor attached to each motor??? To use programable stat you would have to find line voltage stat with rating to handle fan amp . other option is to use low voltage stat and transformer and fan switching relay with fan motor wired through n/o contacts and relay 24v coil energized by low voltage stat.

Nov 25, 2012 | Heating & Cooling

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My carrier AC(model: Optima D plus) is displaying a error "E3". Can someone suggest a solution to it.

An E3 error on your thermostat (T-Stat) has the following description from your manual:

"Brownout condition or too low of voltage to thermostat. Double check wiring and check for
24 vac between R and C. E2 will clear 15 sec after proper voltage is restored."

If you are unsure how to check the low voltage to your t-stat, then please call a professional in your area to check the t-stat wiring and the transformer in your furnace.

Jun 13, 2011 | Heating & Cooling

1 Answer

How do u wire athermostat to the furnance and ac unit on model e3eb-015h nordyne

You need to get low voltage wire known as 5 wire. run wires thru wall to stat and furnace Red wire goes to R terminal white to W terminal Green to G terminal Yellow to Y terminal on both the stat and furnace circuit board. Now you need a wire called 2 wire low voltage wire run that from furnace circuit board to outside A/C. At furnace hook red wire to Y terminal and white to C terminal doesnt matter which ones you hook up at outside unit. Do it just like i told you this will work properly.
If this helps please rate me.

May 20, 2011 | Heating & Cooling

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.

May 11, 2010 | Dometic Rooftop RV Air Conditioner

1 Answer

It won't power on although we know it's getting electricity.

Hi you say it is getting power? These units have 2 power sources to them, high voltage to run the motors and compressor, and 24 volts to the thermostat to control all of the low voltage componants that turn on the high voltage componants. If you are saying you have high voltage, you need to determine if you have 24 volts at the thermostat. Your stat may be faulty, even if the fan comes on when you put it to manual. I don't know what kind of unit you have, but if you turn off all power, go to the stat and remove the cover. There are 3 sections to this, cover, stat and last,sub-base. The stat will have small slotted screws here and there on it. Lossen all of them up and it should pull off. Now you will see the wiring. Find a small piece of electrical wire stripped at both ends. Do this test if the fan runs, and if it don't. Touch and hold the end of wire to the R terminal, and to the yellow terminal. The a/c should come on. If it does, the thermostat is the faulty part. If nothing comes on there most likely is no low voltage to the stat. It will be in the heat section at the transformer, or a small 3 to 5 amp fuse on the circuit board if this heater is a fairly newer one. Do the things I have asked and get back to me so we can go from there.

Apr 14, 2010 | Heating & Cooling

1 Answer

I have a 5 ton air conditioner made by international comfort corporation, it bears the model number PAB036N1LA and I need to know what the diagram is to hook up the thermostat. its a commercial rooftop...

on the unit it should have low voltage termanals labled R Y G H H2 the R termanal goes to the t-stat on the r termanal and the y to y on the t stat ang g to the g on the t stat and H termanal goes to h on the t stat etc if thers no termanal block find the low voltage wires and get back with me on the collors

Apr 04, 2010 | Heating & Cooling

1 Answer

No low voltage to t-stat. already changed transformer & float swtch. and replaced t-stat?????

did you have line voltage to the transformer? Did you have 24volts on
the secondary side of the transformer?

Feb 04, 2010 | Amana Heating & Cooling

1 Answer

No power going to my heating/cooling unit. Tried to replace the t-stat and it is not getting any power. Checked the breaker and wiring at unit and t-stat to make sure they are wired correctly. Any help?

Sounds like a low voltage transformer is bad.

Possible bad relay.

One side of the low volt trans will have 115 volts.The other side should have 24 volts.Going to the heater.The t stat completes this circut when calling for heat.

Some units have a reset on them or a small control fuse.Near the low volt trans.

Jan 05, 2010 | Heating & Cooling

1 Answer

Heat pump will not come on when cooling call for by t'stat. Indoor fan runs and heat pump runs when contacts manually closed but not from t'stat signal.

There are several possibilities the first thing to check is to make sure you are getting low voltage to the control board,if there is no voltage then is a problem with the wire coming from the t-stat,or the t-stat itself, if there is low voltage (at least 24) then you have a faulty control board.

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Honeywell digital thermostat stopped working

Sounds to me like you have a low voltage short. If the stat had no display until you installed the battery means there was no voltage for the stat to work. Putting the battery in proves the stat works, no motors turning on probably leads to a blown low voltage fuse generally a blade fuse on circuit board in indoor unit. Good Luck

Jun 11, 2009 | Honeywell Programmable Thermostat Heater

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