I installed a humidifier (Honeywell HE260A by-pass flow-through) on return pelum and although calling constantly for moisture, I don't seem to be increasing the humidity level in the living quarters. There was no space to install humidifier on supply pelum due to duct work providing heat to an addition.

Yes when you turn the dial on the humidistat 24 volts gets sent to the solenoid valve and it will click open and allow water to flow through it.

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.

get a humidity gauge from radio shack for about 20 bucks. thats the only way to tell. or pay a service compant tocome out for probaby a 100 bucks to tell you what the humidity level is in your home. id get the $20 one a the shack

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.

these are flow thru models and a lot of water passes thru them. The instructions say to not limit the water by closing valve at all!

Replace the Valve on the unit. Check the small filter inside of it where the waterline attaches first. If its clear and you have lots of flow from the 1/4" line the replace the valve.

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

Sounds like you Connected the humid trans fromer directly to a main power source. It should be either on the EAC or HUM term on the board of the furnace.

yes water should turn off solinoid is bad

I am having the same problem. I have had my humidifier for about 5 years now and I just started having the problem where the water continuously flows through the solenoid. I took apart the solenoid by removing the fittings from both sides. When I did that, I noticed that there was a hole in the metal that allowed me to see through to the other side. Apparently, it had corroded and and broken through, allowing the water to pass through the solenoid without really going through the valve within the solenoid. There are several sites that sell replacements for about $70, which is not cheap, but cheaper than buing a new humidifier for $120. Here is one site I found: http://www.iaqsource.com/product.php/honeywell/32001639-002/?product=112783&category=1142