I installed GeneralAire 1042LH. I connected the 24v Transformer to direct current. When I turned the humidistat on water flows. However the water keeps flowing yet it never stops. Any ideas?

Check to see if you are getting 24 volts from the transformer, if not, turn off power to the transformer and check the resistance of the secondary side, if no resistance the transformer is bad and need to be replaced. Also check to make sure all the wires are secure. If you are getting voltage at the transformer then bring power directly from transformer directly to solenoid valve and it should click open and let the water through, if it does then either the sailswitch/current sensing relay is bad or humidistat is bad.

Did you just install this unit, or has it been working for a while and just stopped?
1. If you just installed it, the solenoid wires (yellow) must be hooked up to switch in when you have a call for heat.
a) use a current sense relay OR
b) connect 120V & neutral to "HUM" terminal and neutral on heater control board.
2. If it has worked before, maybe the saddle valve is plugged. Turn the "T" handle all the way clockwise, then all the way out CCW. You can hear the water start flowing. Loosen compression fitting at solenoid valve to make sure water is getting there.
3) Also, you must supply 24V to the circuit to open the solenoid valve. Check your wiring. It depends on the model what way to wire it and I cannot go into that here.
4) Testing: Turn off humidistat control. Turn on heat, wait for blower to come on. Turn humidistat control to test posn. Solenoid valve should click. This will put water into top of Aprilaire tray, after few minutes it will dribble out bottom clear vynl tube to the
drain.

Check if you are getting 24 volts at the transformer, if you are then appy power directly to the solenoid valve from transformer, you should here the solenoid valve click and let water through. If not replace the solenoid valve. If the valve works by giving power directly from transformer the check the wiring, humidistat, and current sensing relay/sail switch.

The system is 24 volt AC so start by checking the voltage from the transformer to make sure it is approximately 24 volts AC. The current will flow through the humidistat when continuity is made at the control as the humidistat senses that your house needs moisture. Disconnect the wires from the himidistat and set it to a high level, you should hear a click on the way up. With the 24 volt wires disconnected, check for continuity with a volt meter. If you don't have continuity replace it. Current also flows through an inductive sensor switch that hang on a wire from the blower. When the blower wire has current flowing through it, the switch senses that an closes makin the connection. With both wires disconnected from the 24 volts you can test for continuity when the blower is running. Overall, this is a continuous circle of wiring and is not directional like DC so think of the wiring a a big loop. The correct current has to flow through the transformer, through the humidistat, through the blower switch, through the solenoid completing the the circle before the solenoid will activate. Hope this helps.

you must not be getting 24 volts at the solenoid, check your transformer to see that its supplying 24 volts and follow the power, also try turning up the humidistat.

Could be a couple of things. Transformer can be bad. Try connecting the two wires (usually wired red and white) from the transformer to terminal W and C on the circut board. Your bypassing the transformer and if installed a current sensing relay. The furnace transformer will/should handle the extra load. Turn on the furnace, if still not working, loosen the water supply line at the water solenoid on the humidifier, if water flows out then your supply valve isn't clogged, if no water then try screwing in the needle on the supply valve all the way in then back out. If still no water then the valve is clogged. If all is good then it looks like the water solenoid is bad or wiring to valve/humidifier control. Don't find the controls bad that often. Have fun!

push sail switch forward by hand to see if that is the problem.
Remove two wires at humidifier and connect them if it starts than it is in wiring, humidistat, or transformer.

the 760 humidifier does not need a transformer wired externally. the 760 has its' own 24v transformer inside the fan compartment. this transformer will provide the power to enrgize the water solenoid as needed. it sounds like to me the additional trasnformer is hot all the time. when the furnace comes on, the unit gets power and the internal transformer is cancelling the power from the external transformer. this would explain why it quits running when the heat is on. since the external transformer is hot all time, when the heat shuts off, the solenoid is getting energized by the external transformer. to make this run correctly, you need to get rid of the external transformer. leave the humidifier high voltage wires hooked up so they are only hot when the furnace runs. if you have a humidistat that has a r and c terminal, you will need to wire these directly to the r and c on the furnace control board and move the switch inside the humidistat to "power". make sure it is not on "bypass". then wire your 2 brown wires from the humidifier to each of the "h" terminals on the humidistat. if you have a humidistat that only has 2 terminals, wire one brown wire to each of the terminals. this should allow it to run properly.

theholts220 - Sounds like they needed to install a bit larger transformer . You can also buy a A 50 Sensing relay that attaches to the wires for your motor and when you turn on the furnace it will allow the power to go to the humidistat. Very strange though they do not use a lot of power. Check and make sure the wires are not pinched or touching metal somewhere.


TLuzzo - The humidistat seems to be working when you turn it down. The wires for the solenoid should be hooked up to your furnace circuit board. The instruction manual will tell you where. If you dont have a spot on your circut board the A 50 sensing reley is they way to go. They are inexpensive

I WOULD CHECK TO SEE IF YOU HAVE ENOUGH V/A OUT-PUT ON TRANSFORMER. I DONT KNOW IF YOURS CAME WITH ITS OWN TRANSFORMER. IF IT DIDNT YOU SHOULD HAVE A MINIMUM OF A 40 V/A RATING STAMPED OR PRINTED ON THE EXISTING TRANSFORMER. IF THE TRANSFORMER IS EXTREAMLY HOT ... YOU MAY NEED A 75 V/A TRANSFORMER WITH THE SAME VOLTAGES. INCREASING THE V/A CANNOT DAMMAGE ANYTHING IT JUST GIVES YOU MORE POWER WHEN EXCESIVE CONTROLS AND WIRING ARE ADDED TO A HVAC LOW-VOLAGE (24v) CIRCUIT. IF YOU LIKE YOU CAN CALL ME AT 727-363-7071. I AM A RETIRED HVAC&R CONTRACTOR WITH 45 YEARS EXPERIENCE. I HATE THE NEW SENSORS THEY HAVE TO ACTIVATE THESE NEW HUMIDIFIERS. I USE TO WIRE THE HUMIDIFIER TRANSFORMER (SUPPLIED WITH HUMIDIFIER) TO THE LINE (110V) SIDE TO THE LOW SPEED ON YOUR BLOWER MOTOR. THAT WAY THE ONLY THING THAT INTERUPTS THE CICUIT IS THE HUMIDISTAT. YOU NEVER WANT THE HUMIDIFIER TO RUN IF YOUR SYSTEM IS NOT "CALLING FOR HEAT". NEVER TRY TO ENERGIZE THE WATER SOLENOID THROUGH YOUR HEAT WIRE(USUALLY SMALL THE WHITE WIRE) FROM THE THERMOSTAT. THIS WILL RESULT IN BURNING YOUR HEAT ANTICIPATOR OUT ON THE T-STAT.