Getting 24 volts on one side of transformer is this a bad transformer

Hello, the control board supplies 120 volts to a transformer and then the transformer steps it down to 24 volts. check to see if you are getting 24 volts at the transformer if not then turn off the furnace and check the Resistance of the transformer, you should read resistance if not the transformer is bad and must be replaced. If you are not getting 24 volts and the transformer checks out good then a problem could be the wires going from the board to the transformer or portion of the control board is bad.

Hello, check to see if you are getting 24 volts to the solenoid valve, if you are and it does not click on to let the water into the humidifier then the solenoid must be replaced. However if you are not getting 24 volts to the solenoid valve check if yuou are getting 24 volts at the transformer, if not then turn power off to transformer and check the continuity of the secondary side of the transfomer, you should have resistance if not replace the transformer. if that checks out good check the wire connection between transformer and solenoid and make sure it is tight. If wire connection looks good then either humidistat is bad or current sensing relay/sail switch.

Hello. the first thing you need to determine is if the solenoid is getting 24 volts when the furnace turns on, you should be getting 24 volts at the solenoid valve. If not you need to start at the transformer and see if you are getting 24 volts there, if not then most likely the transformer is bad and must be replaced, if you are getting 24 volts at the transformer then check the wiring and make sure it;s tight. also check the humidistat and sail switch/ current sensing relay to make sure they are working properly.

Check to see if you are getting 24 volts at the solenoid valve, if you are then the solenoid valve is bad and needs to be replaced. If you are not getting 24 volts at the solenoid valve then check to see if 24 volts is present at the transformer, if it is then check the wiring to make sure it's tight, humidistat, and current sensing relay/ sail switch. If you are not getting 24 volts at the transformer then turn off power to transformer and set your meter to continuity and check the secondary sie of the transformer, you should get resistance if not the transformer is bad and must be replaced.

Check to see if your solenoid valve is receiving 24 volts by using a multimeter and putting each meter lead to each of the incoming wires to the solenoid valve, if you are getting 24 volts and the valve wont open replace the solenoid valve. If you are not getting 24 volts then Start at the transformer and see if you are getting 24 volts there, if you are then the problem is either loose wiring or the humidistat or sailswitch/current sensing relay is bad. If you are not getting 24 volts at the transformer then turn off power to the transformer and set your meter to read continuity, then take your meter and check the secondary side of the transformer for continuity, if none is read then replace the transformer.

Typical Thermostat Wiring for 4 or 5 wire Heat/Cool Thermostat (not heat pumps)
4 Wire Termostat
R = Red One Side of 24 volt Transformer
G = Green Blower
Y = Yellow Cool
W = White Heat
5 Wire Thermostat
with one transformer for both units
Rc One Side of 24 volt Transformer
Rh Jumper Rc to Rh
G = Green Blower
Y = Yellow Cool
W = White Heat
5 Wire Thermostat
With 2 transformers one for indoor unit
And one for outdoor unit
Rc = Red One Side of (outside) 24 volt (outside transformer)
G = Green Blower (outside transformer)
Y = Yellow Cool (outside transformer)
Rh = Blue One side of (inside) 24 volt (inside transformer)
W = White Heat (inside transformer)
COOLING ONLY Thermostat
R = Red One Side of 24 volt Transformer
G = Green Blower
Y = Yellow Cool
HEATING ONLY
R or Rh One Side of 24 volt Transformer
W = White Heat

What are you trying to wire up?
Typical Thermostat Wiring for 4 or 5 wire Heat/Cool Thermostat (not heat pumps)
4 Wire Termostat
R = Red One Side of 24 volt Transformer
G = Green Blower
Y = Yellow Cool
W = White Heat
5 Wire Thermostat
with one transformer for both units
Rc One Side of 24 volt Transformer
Rh Jumper Rc to Rh
G = Green Blower
Y = Yellow Cool
W = White Heat
5 Wire Thermostat
With 2 transformers one for indoor unit
And one for outdoor unit
Rc = Red One Side of (outside) 24 volt (outside transformer)
G = Green Blower (outside transformer)
Y = Yellow Cool (outside transformer)
Rh = Blue One side of (inside) 24 volt (inside transformer)
W = White Heat (inside transformer)
COOLING ONLY Thermostat
R = Red One Side of 24 volt Transformer
G = Green Blower
Y = Yellow Cool
HEATING ONLY
R or Rh One Side of 24 volt Transformer
W = White Heat

Typical Thermostat Wiring for 4 or 5 wire Heat/Cool Thermostat (not heat pumps)
4 Wire Termostat
R = Red One Side of 24 volt Transformer
G = Green Blower
Y = Yellow Cool
W = White Heat
5 Wire Thermostat
with one transformer for both units
Rc One Side of 24 volt Transformer
Rh Jumper Rc to Rh
G = Green Blower
Y = Yellow Cool
W = White Heat
5 Wire Thermostat
With 2 transformers one for indoor unit
And one for outdoor unit
Rc = Red One Side of (outside) 24 volt (outside transformer)
G = Green Blower (outside transformer)
Y = Yellow Cool (outside transformer)
Rh = Blue One side of (inside) 24 volt (inside transformer)
W = White Heat (inside transformer)
COOLING ONLY Thermostat
R = Red One Side of 24 volt Transformer
G = Green Blower
Y = Yellow Cool
HEATING ONLY
R or Rh One Side of 24 volt Transformer
W = White Heat

Typical Thermostat Wiring for 4 or 5 wire Heat/Cool Thermostat (not heat pumps)
4 Wire Termostat
R = Red One Side of 24 volt Transformer
G = Green Blower
Y = Yellow Cool
W = White Heat
5 Wire Thermostat
with one transformer for both units
Rc One Side of 24 volt Transformer
Rh Jumper Rc to Rh
G = Green Blower
Y = Yellow Cool
W = White Heat
5 Wire Thermostat
With 2 transformers one for indoor unit
And one for outdoor unit
Rc = Red One Side of (outside) 24 volt (outside transformer)
G = Green Blower (outside transformer)
Y = Yellow Cool (outside transformer)
Rh = Blue One side of (inside) 24 volt (inside transformer)
W = White Heat (inside transformer)
COOLING ONLY Thermostat
R = Red One Side of 24 volt Transformer
G = Green Blower
Y = Yellow Cool
HEATING ONLY
R or Rh One Side of 24 volt Transformer
W = White Heat

You need a serviceman. No really, you do! You are in over your head and you are replacing parts just because you can see them and they are not the likely culprit. I am betting it is the contacters in your condensing unit.