#24 VOLT TRANSFORMER INSTALL#

If its over that, the transformer is putting out to much on the secondary side and should be replaced, or it will eventually take all of the low voltage controls out. I would, if you have a volt meter check the incoming voltage to the stat to make sure it doesn't exceed the proper voltage rated on the cover.

If so, the circuitry is going out and you will need a new thermostat. A 2-stage heat-pump stat? I would remove the front to expose the wiring terminals and pull the hot wire red, 24 volts and that should kill the buzz. Hi, relays will also buzz causing units to loose transformers, I have seen this in the past years also. Normally you should read 24 volts between RED and COMMON If you have no power to these terminals when calling for heat or cool or fan then yes the thermostat is defective and requires replacement.ДO NOT let the RED wire touch ground or the COMMON terminal, this is a direct short and blows the fuse or transformer Same for Cool which is the Yellow or Y terminal. Same for Fan which is the Green or G terminal, So between terminals Common & White, it should read 24 volts during a call for heat. If the thermostat is powered by the transformers 24 volt power, there will be a 'COMMON' wire on the common terminal of the thermostat, this is the other side of the 24 volt power from the transformer, the side opposite from RED the 24 volt 'hot leg'Д¬ommon is called common as its the side of power that EVERYДў4 volt circuit terminates, or completes its circuit, thus the COMMON designation.Дuring a Heat call the 24 volt hot leg is sent out via the white/heat terminal to the gas valve etc. Red enters the thermostat on the Red or R terminal, some thermostats will have an RC and an RH terminal, these are jumpered together on single transformer systems as they are for Red Cool and Red Heat, without a jumper wire on RC and RH, the Red 'hot leg' of the 24 volt control voltage will only energize the terminal its wired to, some stats are battery powered and do not use the transformers 24 volt power (parasitically) to power the thermostat. Red is the 24 volt 'hot leg' of 24 volt power which originates at the transformer. You will need a volt meter to test further.ДЄt the thermostat remove the cover thus exposing the thermostats sub base and assorted circuits/wiring. If you do not get any fan operation by switching the fan switch to the ON setting, you then will have to determine if the breaker, transformer and aforementioned 3 amp fuse are all good. This saves you from having to go to the breaker panel and checking / resetting the breaker as well as checking the Transformer and automotive type 3 amp control circuit fuse (generally on the circuit board). Go to your thermostat and look at the FAN switch, it will be in the AUTO position typically.Д«y doing this if the fan motor operates you know that the High voltage & the low voltage (24 volt control power) are present. Now you can go through your low voltage wires one by one and test them unhook all the wires to your outdoor condenser at your indoor unit(furnace or airhandler) and try turning it to cool now if you blow the fuse the short is between the tstat and the indoor unit if the fuse is still good leave it on cool and hook up one wire at a time to your outdoor unit starting with R a lot of times your contactor or your defrost board will short out on you also look for pinches in wires wires with cracks in the insulation and wires touching metal this situation can be a real pain sometimes i would recommend calling a hvac company if you start to get stumped

#24 VOLT TRANSFORMER INSTALL#

Blown transformers are usually from a low voltage short the first thing i would do is wire a automotive or resetable 3amp fuse in line with the transformer so you dont blow transformer after transformer the wire coming off the transformer that say 24v take that wire a couple of inches down and cut it and install the fuse in series there

24 volt transformer