Question about Heating & Cooling
I have 2 exact ac & electric heat units. Transformer went out on one had a ac company???? come out he changed the transformer and when he left the heat came on when the air should and etc everything wrong. I looked at my other unit how it was wired and changed the wiring they done back to how my other uit was wired and everything works fine now except outside compressor does not come on when stat calls for it. New compressor connector new transformer.
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Posted on Jan 02, 2017
Do you have gas or electric heat. If you have gas then you do not have a heat pump. You should in most cases have a red,yellow, white, and green wires coming to the thermostat. R should go to rc/rh G should go to green Y should go to Y and w should go to W. Also the switches on back should be switched to non heat pump and gas rather than electric. Hope this helps.
Posted on Feb 16, 2009
SOURCE: burning up transformers
YOUR the first person that has gave enough information to help in a WHILE THANK YOU SO MUCH!!
Start all over from first
I'm betting that you need a fuse in both sides of the transformer until you find the real reason they burn up.
A solenoid valve that sticks can cause the transformer to blow but so can a lot of other things, namely anything in the control circuit that uses the 24V power. A relay or contactor that doesn't pull in or a defective defrost control, a shorted wire from the thermostat.
I'm wondering if you have what we call a package heat pump meaning the both the indoor blower and out door compressor & fan are in the same section out side? OR is your a split system with an indoor section and an outdoor section?
I'm betting on the split section. In some miss-matched systems (like a Lennox indoor and a GMC out door for example) Some of the origonal Lennox heat pumps had an out door and an indoor transformer. If these trans formers were not "phased" together it could cause a problem like your having. Now you just have it in the heatign mode if I read between the lines correctly. So it makes snece that it's something with the heat. The out door unit can opperate withits own 24v but if you have back up heat inside (gas or electric Im thinking you have electric) the indoor section will come on atfter a few more degrees of heat loss (2-4'F). This is where the transformer inside will buck the one outside and somethjing has to give. The weakest point.
From what ive been told by some of the old hands I've been around if the high volt side burns out look for a low volt problem if the low volt burns out look for a line volt problem.
If this has 2 transformers like I suspect try the fuse on both sides but remember the one is hot and will remain hot all time on 220V or 1 leg of it or it might remind you. To phase these transfoprmers I believe you swtich the main lines L1 & L2 at either of the transformers. Now 1 more thing the indoor section may be using ground on the low volt side as a path for 1 side of the transformer. I believe you will ahve to do same for the other transformer too.
Hope this helps Id really like to know what you find and do.
Please ask more and you give such detail I can follow you with little trouble. Please rate me as high as you can and good luck.
Posted on Mar 30, 2009
Look at the contactor on the condensing unit, remove the low voltage wires to the contactor and turn on the system. If the low voltage fuse doesn't blow, replace the contactor.
Posted on Jul 07, 2009
Hi, you do have a dead short in the control side of the system. Good that you bought a transformer with the breaker. Most people don't and will smoke several of them. Anyway, it is a split system. If it was iced up, it must be a heat-pump, not gas fired. The problem will be in either the stat wiring from stat to indoor unit, to outdoor unit, and if a wire is not grounded in the stat wires, one of the 24volt controls have a dead short as the breaker trips instantly. Here is what you will need to do. You will need to do a process of elimination on all of the 24volt controls. I would start at the outdoor unit as you engaged the contactor by finger to check for power. If you see no stat wiring outside touching, the coil on the contactor is 24 volts and may be the shorted control. Coil could be bad. Pull a wire off the coil,there will be 2 wires at the sides. I am sure you know which are the low voltage controls if you can replace a transformer, this is great. You can find this pretty easy. If you pull a wire off one side and reset the unit and the breaker does not trip, then you know the low voltage coil is compromised. If it trips, go to the next low voltage control as the 24 volt coil on the rsv ( reversing valve ) and unplug it. If you have the schematic handy, it will show you all of the componants on the low voltage side/secondary side of unit that you will need to check until the breaker stops tripping. This is the best way to find the culprit!! I have done this for 33 years as a contractor and I am sure you will find this short very soon by doing this. Here is a tip for you also. Sometimes on the transformers that have these tiny resets on them, will wear out pretty fast. What you can do is take a 3 to 5 amp automotive type fuse and on the 24 volt side of the transformer you just cut the red/ hot wire/24v. and crimp a female stak-on to each end of the wire you cut. Then plug each end onto the fuse.Use some electrical tape around it so any bare metal that may be showing will not touch and blow fuse. This is a good way to protect all transformers that have no breaker if you end up with a short. Cheaper to replace a fuse then to keep replacing transformers every time! The fuse will just blow and you can start looking for the short. Now on your unit you can go to the indoor section where the transformer is that you put in. You can eliminate the thermostat and control wiring to the indoor unit and outdoor unit real fast so you know where or which section the short is in. Just kill main power, now where your stat wiring terminates you will disconnect from the control board. Since you have a heat pump you will have more control wires to work with, so either draw a diagram or use the one on your panel to reattach. Remove the wires from the board that take off to the stat first and supply power back to it. If the breaker holds, you will know the short is either the stat wiring from the indoor unit are touching somewhere/grounded or at the stat.You will then know that's where the short is as you have narrowed your search way down. If it trips, you will do the same to the control wires that go to the outdoor unit. If you disconnect it at the board and it holds, you will know it is from the wiring there to the outdoor unit! So, you either have wires grounded from there out or a low voltage control part has burned out. If you remove all of the control/thermostat wires at the board to the indoor and outdoor unit and it still trips, the short will be in the indoor unit which will more then likely be the board itself. Yes sir, this is really a very easy fix for you and I feel you have the ability to do this checks your self. The short has to be on the low voltage side of the transformer as you have proved that! You traced it right back to the transformer secondary low voltage side. So, just take your time and follow my instructions the best you can, and you will find out which part of the system the short is in and then narrow the search down further! I have a hunch the coil is burned/shorted on the contactor :) A place to start by pulling one little wire off the coil. I know this is a long explanation but I wanted you to understand and help you as much as possible on how to tackle this. Sounds difficult but it is not at all. It is either a low volt componant on the outdoor/indoor/ thermostat/ or stat wiring. If none of those, with all low voltage wires removed at board and it still trips, the board is shorted to ground. You can kill power to indoor unit and carefully take the board loose to look at the back side for any hot spots and you will know its the board. I had one totally smoked on a 5 ton package heat pump yesterday in fact!!! I could not see it until I pulled the board/defrost board out far enough to see it, but I knew it was the problem as it would not control the reversing valve, fan control, or run the condenser fan motor. Please drop me a line and let me know how you are doing, please. I would love to know that you were able to find it as I know you will. Best of luck to you.
Posted on May 06, 2010
SOURCE: My dog chewed up the
Hello,Yes there is a 3 amp blade fuse(same as in a car) in the blower unit,take off the door and it is plugged in to the(curcuit) board.Pull it out and slip a new one in.That will restore the control voltage.Your repair sounds correct.Some times there is a tiny button on the transformer itself (square box) that pops up instead of a fuse just push that in to reset it(if applys).
Posted on Oct 19, 2010
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