I purchased a bypass flow through humidifier from Honeywell and replaced and older unit. Installation was easy as I used the old thermostat and unit appears top be running fine... The problem is a had an extra part,, the transformer...The instruction did not show how to hook up and my question is do I need it, if I did not change the humidity thermostat?? The unit is a Honeywell HE220A,B
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Re: how does transformer hook up
If you just replace the unit and it is working, no your do not need the tranformer. The unit is getting power from the furnace. For reference though. The black and white wires are your 120 volts. Black hot, white common. the 2 screws are your 24 volts
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It's not uncommon for duct work in an older home to Bang as the furnace cycles due to age. The humidifier banging while turning on and of is mostlikely the solenoid valve; if the solenoid is bad it is actually to your benefit to replace the entire humidifier as the solenoids are very expensive, 50%+ of a new humidifier. Plus you get the 5 year parts warranty on the new unit instead of just one year on the solenoid. If you don't want to replace the entire unit you can replace the Humidistat, and that should fix the on/off cycling, however a new humidistat is included with a new unit, which again is more cost effective. They are easy enough to replace as a do it yourselfer, especially when replacing an existing unit. I hope this helps you.
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.
If you have very old furnace, does it have a blower with a belt. If it does it should only have 2 wires going to blower. If it has 2 you should be able to use the transformer you have plugged into wall and splice into 2 wires going to blower. If you have more than 2 wires to blower, you will need to find out which one is used for heat plus use the white one. If you have a voltage sensor you should be able to find it easily.
Could be a couple of things. Transformer can be bad. Try connecting the two wires (usually wired red and white) from the transformer to terminal W and C on the circut board. Your bypassing the transformer and if installed a current sensing relay. The furnace transformer will/should handle the extra load. Turn on the furnace, if still not working, loosen the water supply line at the water solenoid on the humidifier, if water flows out then your supply valve isn't clogged, if no water then try screwing in the needle on the supply valve all the way in then back out. If still no water then the valve is clogged. If all is good then it looks like the water solenoid is bad or wiring to valve/humidifier control. Don't find the controls bad that often. Have fun!
it is best to use a seperate transformer for the hummidifier, but in some cases you can use the low voltage t-stat wire that runs your furnace, you will need to have one wire run to common, and the other to the heating side of your low voltage, normally its the red wire hooked to the w circuit of your terminal board, if you do decide to go with an extra transformer, make sure you you have it wired to bring on the humidifier only when the unit calls for heat, hope that helps
I also had the transformer problem and it was made worse but an HVAC guy who rewired the furance fan to get more air flow when he installed a new AC unit. He left the humidifier wired to the old fan windings which were now putting out 160 induced volts. The humidifier transformer, which was already undersized by Honeywell, never had a chance. Not sure how common this problem is but I later saw several references to the same problem on other websites and it's worth a quick check of the supply voltage to your humidifier.
Since I had an expensive humidifier and a whole cut in the furnace duct, I looked for a fix. My solution was to buy a $15 transformer from a BigBox that matched the voltage and was oversize on amps and mounted it externally to the humdifier (much like a furnace transformer is typically mounted). I then completely removed the piece-of-junk humidifier circuit board and wired the transformer directly to the water solenoid which it controlled and wired the fan and new transformer directly to 120V that is controlled by a current sensing relay (Aprilaire A50) on the furnace fan wires (and also controlled by a humidistat located on return air plenum).
It has worked fine for two years now, runs only when the fan is on and when the humidistat is asking for more humidity. A relatively cheap fix that would have only taken an hour if I had done it right from the start.
For those of you who haven't bought the Honeywell 360A yet - don't. For those of you like me that spent the money and cut holes in your duct - this is one solution.
Maybe Honeywell will wise up and redesign their transformer PCB to be much more robust. The rest of the unit is a pretty good design.