I have a aprial air 400a. I have aready checked resistance from oat. It is fine. I have 24v at solenoid valve until I connect the leads to the actual valve. Then I loose voltage. The way I have it wire Is with a constant 24 volt to r and c at the humidisat. A constant circuit from w on on furnace to the h term at humidistat then from the w term at fur to to solenoid. the other side of h term at hum stat also geos to the other side of the solenoid.. I know the solenoid is fine cause if I wire a direct 24v to the valve it come on with no problems. I cant find a wiring diagram anywhere for this particle model.

If humidifier is running but water valve is not clicking open, check the wire connections. If connection is OK, than unplug the humidifier from 120V outlet, disconnect water valve wires and with multimeter check resistivity on the valve coil. If the coil is burned out/open/no resistance, the coil needs to be replaced.

It sounds like it is just miswired. The low voltage wiring off the humidistat should be on W and C on the circ. board at the furnace. If you have it on R and C then it will power it constantly regardless if the heat is running or not. W is only energized on a call for heat which is typically when you want that type of humidifier to run

Hi,
Sounds like you are not getting the proper voltage to the solenoid valve...
Check for 24v coming off of the transformer...that may be 24vac not vdc...

Then check to see if there is power coming from the humidistat...
unhook the wires to check for the power at the solenoid valve...
check across the two wires...

if there is power the valve is bad and that alone will cost about 90 bucks with shipping...
if there is no power trace back and see where the power stops at...

heatman101

Check for 24v.hum transformer shuold interlock/power up during blower motor hearing speed operation.Make sure its running.also manual mode resistor has to be installed in control panel.a blue plastic tag w/2 ends.

You can add a solenoid valve without an issue. Most units come with a 40 VA transformer and that is usually double what the actual demand will be.

The coil may shorting out the 24vac supply to the solenoid. Recommend replacing soleniod.
Normally you should be able to read the 24vac across the solenoid when energized.
The other option is to get a 120vac to 24vac transformer and test the solenoid. This way you will know if the solenoid is the cause or the 24vac source is the problem.

the change water panel light is just a timer. it does not sense that the water panel actually needs to be replaced. sounds like you have a solenoid issue. if you have water to the solenoid and are certain you are getting 24v to it, the solenoid is ethier bad or plugged with calcium. most likely calcium. sometimes you can take them apart and clean them. so, it you can hear clicking at the solenoid when you turn the humidstat up and down. try cleaning it.

No. when you remove the front cover it will automatically disconnect the power supply. Try changing the water panel and cleaning out the orifice and filter screens located in the water lines connected to the solenoid valve.

Easy fix: Check the solenoid. Turn off the power to your humidifier and the central air unit. On the side of your humidifier is a brass solenoid. It can get clogged with lime and calcium. Most videos and instruction manuals tell you to replace the solenoid. No need if you can turn a wrench.

1. After all power is off turn the water off to the humidifier and disconnect the top line water line at the nut.

2. Disconnect the bottom line water line that will go to your humidifier.

3. Take a Philips screw driver and remove the two screws that hold the solenoid on the side of the plastic housing of the humidifier.

4. Leave the wires connected unless you need more room to work. If you disconnect the wires then label them with tape (colored) so you put them back on correctly.

5. In the inlet or outlet water pip of the solenoid is a trainer that may be clogged. With a paper clip pull it out and clean it. If it’s clearly clogged then stop and put all back together. That may have been your problem.

6. If it’s not clogged then it may be clogged inside the solenoid.

7. The nut on the end of the solenoid is silver. Take it off and the magnet (main power unit) will slide off.

8. Notice the flat head screw post on the end of the solenoid. Turn it and remove. Be careful as a small spring loaded plunger is inside.

9. Take apart and clean all parts. You should be able to blow air in the intake water line tube and it go out the out water line tube as well as were the plunger hits in the center of the solenoid. If not then it’s clogged.

10. If clogged then just soak all but any parts with rubber or plastic in a small white vinegar solution for a couple of hours to eat away that lime. If it’s not clogged then you probably have a bad solenoid.

11. To check and see if the solenoid is bad just put it all back together but do not re-wire the solenoid to the humidifier.

12. Turn on everything without the wires going to the solenoid (turn on meaning put power back to the unit.

13. When the system is running as it should without the humidifier and solenoid wires attached check the two lead wires with a volt meter for 24v. If you have 24v then you have a bad solenoid and need a new one. If no 24v then you may need a new control panel.

Hope this helps you out.

The controller is faulty. The previous question was hopefully to help determine why it faulted. The switching for the solenoid is a solid state device that is allowing the 6v through but not getting turned on hard enough to supply the current to operate the solenoid. I am assuming that you checked the voltage with the solenoid connected. If you disconnect the solenoid and look at the voltage it will probably be 24v. If you are not comfortable troublshooting down to the component level a new controller will be your best bet. It may be that the transistor that drives the solenoid could just be replaced. You would have to look at the signal that drives it to determine if it is being turned on with adequate signal.