Where do you install it at supply of return duct work???

Yes thats how it works If you think the flow is too fast turn down the flow , with the valve on the water line .

If the humidifier is a flow through bypass or fan powered it can be mounted in either the return air duct or supply plenum.

Humidifiers are installed in the return air unless they are a forced (uses a fan) type of humidifier.

Evaporative should be in the return plenum and steam in the supply plenum.

Hello Which came first the chicken or the egg?The unit will operate perfectly in the supply OR return as I have installed in both.If there is more room & easy service access put it in there.

hi you will be pushing wet air over air filter and the fan unit , don't think this is right

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.

thanks for your question,
you have to install the bypass humidifier on the supply side of your heating system, (hot side) and run a bypass pipe from the return side, (cold side), it does matter which side it goes on, you do not want water vapor going directly into your furnace, as this can damage it and shorten the life of it, your humidistat is installed on the return side of your duct work, this will allow proper operation of the unit as the humidistat senses the moisture in the air and brings on and shuts down the humidifier as needed. hope that helped to answer your question, please let us know what you think, again thanks, mr.grzz

you are ok. this way humidity will get to whole house if your supply duct splits off. done this way often.

THE MOTOR ONLY TURNS THE SPONGE DRUM AT MAYBE 10X'S PER MINUTE. THIS IS A BY-PASS TYPE HUMIDIFIER THAT RELIES ON YOU FURNACE BLOWER MOTOR TO SUPPLY AIR ACCROSS THE SPONGE MEDIA. NOTICE THE 5"-7" ROUND HOLE MUST BE DUCTED TO THE PLENUM OR RETURN AIR. (IF MOUNTED ON THE PLENUM, THE HOLE HAS TO BE DUCTED TO THE RETURN AIR, AND VISA-VERSA.) CAUTION!!!IF YOU HAVE CENTRAL AIR? A "DAMPER" MUST BE INSTALLED AND KEPT CLOSED THROUGH-OUT THE "COOLING SEASON". SERIOUS DAMAGE TO YOUR COMPRESSOR CAN RESULT FROM TOO COLD OF AIR ... CIRCULATING AND "BY-PASSING YOUR EVAPORATOR COIL".