Our water constantly runs to the Arpilaire humidifier and then it drips out the hose to drain. I was told by our furnace installer that this was normal. I do not understand why the water must run 24/7 and waste all that water that is not used. I would expect the run to run when needed?

humidifiers have a drain and if there is water going in it will be coming out the drain. check drain to see if it is clear, check hoses going into top of humidifier for cracks, check filter in humidifier.

Is the drain line clear?

Hello, no the humidifier should be running only when the blower motor is running. Sounds like the solenoid valve is faulty if water keeps drainig from humidifier.

Hope this helps, check and see if humidistat is set to 35% humidity and that bypass damper on humidifier is in the open position or winter position.(humidistat is usually located on cold air return duct near furnace). Next, replace humidifier media pad, remember to replace media pad (filter) annually, you also may want to clean any lime deposit out of humidifier housing with a solution of warm water and white vinegar before installing your new media filter.Remember to turn power off at side of furnace when cleaning humidifier and replacing media. Before installing new media turn power back on to furnace, set humidistat to the on position, turn furnace thermostat above room temp., and inspect humidifier to see if water is running from top,(you may want to have a bucket under humidifier when checking for water), if you see water running, turn power back off to furnace, properly install new media filter, reconnect humidifier cover & set humidistat to 35%. If you do not see water present, check water supply valve to humidifier and make sure its turned on. If water supply valve is open, then check water supply tubing for blockage.And the last things to check is to make sure all registers through out your home are open and not blocked by any objects, also make sure furnace filter is cleaned, if none of this works refer to installation manual to see if humidifier was sized and installed properly, Good luck.

If the water stops when the heater is not running then the humidifier is working fine. I know it seems like alot of water but that's how it's designed.

Neither, even if the solenoid or humidistat stick, it should always drain properly. Is the unit mounted on the cold air return duct or the supply plenum? If it's mounted on the supply plenum, the water panel might be getting blown forward and spilling the water. High efficient furnaces also can leak water on the floor if its drain is restricted. If hum. is mounted on return duct make sure drain is clear by blowing through it. On Honeywell hum's I've seen the rubber hose from the solenoid valve to the distributor tray leak too, check the rubber 1/4" hose.

No, it will not stop flowwing if it is the water supply. A solenoid valve opens the flow everytime there is a call for humidity, but it stops at the humidifier when there is no call, so it will leak from that point until it is fixed or tightened.

Install new water panels yearly. On the new panel make sure that the painted dot on the edge of the panel is on the top when you install it.
Always clean the distribution tray and the frame. Make sure the notch on the edge of the distribution tray faces away from the furnace. Make sure the humidifier was installed level. Keep the drain tube opening clear. Insure there is no blockages in the drain tube.
Good luck
HVAC Teacher

Have you measured the amount of water dripping into the drain? The specification is 1 quart in 2 and half minutes. If it is much less, get your solenoid checked. I had the same problem and got it replaced and it works as per specification now. You also need to see how many minutes in an hour your furnace is actually running. The humidifier runs only when the furnace is, so the more it runs the better. The specification is 35% with the furnace running at 70%.

I installed this humidifier (and had a lot of trouble installing it!) and was surprised by the flow of water. Mine leaks out of the bottom of the unit so I haven't actually used it yet. I'll try to figure out why it's leaking this weekend. I thought there would be less water flowing through the pad. I suspect that the weight of the unit is causing it to not be plumb so some water is dripping off of the pad and past the drain tray.