I have a HoneywelI Enviracare Elite whole house humidifier. I have no power to the thermostat. The wire goes into the furnace and is attached to a control board. The furnace is working. Humidifer is n

It sounds like the wiring for the humidifier may not be correct. The solenoid valve, which controls the flow of water to the humidifier, should be wired to the humidistat and the transformer, not to the furnace or fan. It is possible that the bottom wire of the solenoid is connected to the wrong terminal on the transformer or humidistat, or that the top wire is connected to the wrong terminal on the humidistat. I recommend consulting the installation instructions for your specific humidifier model, or consulting a professional HVAC technician to verify the correct wiring.

Yes - but it doesn't have to work that way. There are several methods you can use to have the humidifier run only when the furnace runs. Look on the back page of the installation instructions. The method I chose was to install a sail switch. This is a switch with a arm attached which has a "sail' attached to it. When the furnace blower runs, the sail catches the blower airflow and activates the switch; allowing the humidifier to operate.
You can also wire in a current sensing relay (figure 6 on the instructions) or connect the humidifier directly into the furnace motor ignition box (if so equipped. My furnace dates to the late 70's and has no place to plug in a humidifier; which is why I installed a sail switch.)
Now however I probably would go with the current sensing relay option as this looks to be the easiest route to follow. Honeywell has their 32001754-001 avaliable for less than $35 from Sears.

The sail switch is in the cold air return it is wired in with the humidastat when your furnace goes on the air movement pushs the sail down inside the duct work that makes a contact the lets the 24volts to the humidastat. If the humidastat calls for moisture it turns on the humidifier but only when the blower on the furnace is on So in short it detects air movement

Yes you still need a transformer the hum. port on the furnace goes to the 24 volt transformer. one leg of the primary side goes to the transformer and the other leg of the primary goes to the neutral on the board. Then you have your 24 volt terminals one goes directly to the humidifier and the other goes to the humidistat the other wire from the humidifier goes to the humidistat.

hook up the new transformer to the white (common) from the blower motor, and the lead from the blower motor hooked up to the heat term on the board. (just cut the wires and wire nut all three together)

If you chose to install this with an auxilary transformer. Turn the main power off to the furnace. Mount the transformer on the handi box to the furnace or inside the furnace cabinet. Wire the primary wires from the transformer to the main power coming into the furnace. Connect black to black and white to white. Wire the secondary side of the transformer in "series" with a #50 relay, the humidistat, the solenoid valve and back to the transformer. Determine which wire powers the blower motor for the heating speed. Clamp the #50 relay to the wire.
Good luck
HVAC Teacher

24v ac cyliniod on the water line, probably mineral deposits or just went bad, it gets its power from the terminal board on newer units have a humidifier output on them, check there to.

You may need to replace the valve that is wired to the furnace that controls the water flow

sounds like to me you have a condensation pump attached to your hvac system. this can be used to pump water produced during the cooling of your house when in the a/c mode. if you have a typical bypass humidifier, you will have excess water running past the water panel and it must be sent to a drain of some kind. I would imagine the pump is being used to get your bypass water to the drain. another scenario may be that you have a 90% condensing furnace. if your exhaust pipe for the furnace is made out of pcv pipe, it is a condensing gas furnace. it will produce water when it is running. the water if from the combustion gases being condensed in the secondary heat exchanger. this is normal. some condensing gas furnaces will draw combustion air from inside the house and some will have a second pvc pipe that is used to pulll combustion air from the outside of the house. either way, it is not dehumidifying your house. the humidifier should be able to keep up if it is runnng properly. you should have water running out the bottom drain of the humidifier any time the fan on your furnace is running and the humidistat is calling for humidity. if this is not happening, it is not wired properly.

if you just replace the unit and it is working, no your do not need the tranformer. The unit is getting power from the furnace. For reference though. The black and white wires are your 120 volts. Black hot, white common. the 2 screws are your 24 volts