I have a Honeywell HE225A humidifier installed on my Trane furnace. Due to water noise the solenoid on the unit was disabled and a new solenoid was mounted in the rafters to eliminate the noise. This solenoid has now failed. I am trying to find a replacement part. The solenoid is a KSD Com., Type HB1, Orafice 1/16, AC24V, 6AAV, MH26533 with a mounting bracket. Where can this be purchased or is their another suitable solenoid that I could buy?

Sounds like the high pitched noise is coming from the solenoid valve which allows water to enter the humidifier. Typically when the water pressure is too high, it causes this high pitched sound at the solenoid valve. You can adjust the water pressure a little at a time and see if it helps, just make sure you’re getting enough water across the water panel.

Make sure the new pad you installed is in the right position. The pad is marked with a black dot about the size of a quarter. This end should be up for proper water flow through the pad.I fwater flow is being restricted at the pad the vibrating nosie that you are hearing is the dry portion of the pad vibrating agaist the platic housing of the humidifier. This noise stops once the pad has absorb enough water in this area of the pad.

Put the humidifier number, not the solenoid number, into Google or directly at www.appliancefactoryparts.com . They show a breakdown of the humidifier and let you order replacement parts. I've just ordered the solenoid assembly, which they say is in stock.

If there is water and power to humidifier you need a new solenoid valve or humidistat.

I have same problem with no water flow on identical humidifier but was able to fix it. Removed the inlet to the solenoid valve and found (1) a small taper mesh filter inside (2) a small diameter orifice that was clogged. Cleaned the miniature filter and used a sewing needle to open the orifice and now works perfectly.

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.

Furnace mounted humidifiers "should" be wired so that they are only running when the furnace blower is on. When the furnace is off so should the humidifier. If it is wired proper, it is possible that you have a bad solenoid valve. It could be stuck in the on position. If it is bad these valves can be expensive. If your humidifier is newer, fix it. If it is old you are probably better off to just buy a whole new unit.
Good luck

I has the same problem with my HE360 unit. The unit was in fact miswired. The head unit red wires were connected directly to the blue solenoid wires, and activated the solenoid without any signal from the humidistat. As soon as the unit is plugged inn, the water starts running without any signal to the unit. If your unit is miswired, the soleniod blue wires need to be cut and connected to the red crimp connectors.

If the manufacture says it is the IFC then you should have the IFC checked by the company who installed it if it is under warranty still

Try turning the water valve going to the soleniod down. There may be too much pressure. You may have to replace solenoid one more time after making the adjustment.