How to connect the wires from the H8908A Humidistat and HE225 Humidifier to a carier model 58 STA090-14 furnace please? Thank you.

It sounds like the wiring for the humidifier may not be correct. The solenoid valve, which controls the flow of water to the humidifier, should be wired to the humidistat and the transformer, not to the furnace or fan. It is possible that the bottom wire of the solenoid is connected to the wrong terminal on the transformer or humidistat, or that the top wire is connected to the wrong terminal on the humidistat. I recommend consulting the installation instructions for your specific humidifier model, or consulting a professional HVAC technician to verify the correct wiring.

Hello, since this humidifier has a transformer installed with it, you bring one wire from humidifier to Humidistat and then a wire from humidistat to Transformer. You will need a current sensing relay to turn the humidifier on and off with the Furnace cycle. I will attach a link for a wiring diagram for your Humidifier http://docs.electronicaircleaners.com/aprilaire_700a_installation.pdf

HI

I have similar isssue with HE220 but in my case the water run through all ththe time, even when unplugged from the power outlet.
Would that be solenoid issue?
the unit run fine for last season so the wiring is fine.

Any ideas would be greatly appreciated.

Hello, in order to turn your humidifier on with the furnace the 120 volts coming from your humidifer you must hook it up to a step down transformer, then the transformer will provide 24 volts to you humidistat and solenoid valve. So you need a wire from the HUM on your control board to transformer primary side and a wire from neutral on the board to primary side of transformer. Then you need low voltage wire from secondary side of transformer to humidistat from humidistat to humidifier.

Thank you for contacting us. Does your humidistat have a blower activation switch on the lower left hand side of the humidistat? If you do it is our #60 humidistat, and if it is not there you have a #58 humidistat. The R & C are the two connections that supply power to the humidistat to give you the numbers on the digital display. The 60 you wire right into the R & C off the furnace panel. The 58 you need a constant 24 volt and 10 VA power source which you could get by using the transformer off a constant 120 volt power source to power the humidstat. If you are doing this correctly and you still do not get the numbers to show up, then you have a bad humidistat and you need to go back to where you purchased it from and exchange it under warranty provided you used a certified HVAC contractor to do the installation. Our warranty is only valid if you used a certified HVAC contractor to do the installation. If you have any additional questions please contact us at 800-334-6011.

Thank you

www.aprilaire.com

Kevin Engen
Customer Service
Research Products Corporation

connect a 24 volt,20 va transformer to the wires supplying power to the indoor blower motor of furnace, connect the primary wires to heat speed of furnace motor, then connect the two low voltage wires to the secondary side of transformer, good luck.

Maybe I can help. this is 24v so it doestn't matter which wire goes where so here goes. 2 wires from humidistat go to furnace, split one of the wires(not both) so they reach the yellow wires on the humidifier. with marettsconnect one of the split wires to one of the yellow wires. do the same to the other split wire and yellow wire. what you should get is one wire from humidistat to furnace then one wire from humidifier to humidistat and one from humidifier to furnace. hope this helps

Thanks for your question Mike,
The wiring for your humidistat and solenoid are fairly simple, you will need 24volt t-stat wire, you have the two wires at the Solenoid, one wire goes to the terminal board at the furnace, it connects to the (c) or common terminal, the other wire connects to one leg of the humidistat, run another wire from the other leg of the humidistat, to either the HUM terminal on your furnace circuit board, make sure its not a 120v leg, should say in the owners manual, if if is or your not sure, connect that same leg to the (w) terminal at the furnace, this way it only comes on in heating mode, some models need a second 120v-24v transformer, but you would still wire it through the same way, only exception is that you have to hook up 120v to the transformer, and route your wiring like I told you above but through the transformer to complete the circuit, hope that helped you out Mike, please let us know, thanks again, mr.grzz

I suppose you are looking at the do-it-yourself model. Depending on the wire that is run up to you Regular Thermostat from your furnace. You may have to run a seperate line for the Humidistat. A digital thermostat that does Humidity and Temperature is recommended. Or you could just place a Humidistat near the furnace room. A wiring diagram will come with the Humidifier discribing the different ways to wire it.