Install for General 1042-L humidifier

[davidbach]

Hello,

Today, I wanted to check if my furnace humidifier was working.
With furnace running, I pulled out the water supply to top of the unit and it was dry. After checking several things, I finally found that the transformer was not putting out any volts. 24 volt transformer. I did verify the line in leads had 120v. Well tomorrow I will see if I can find one locally, or I will order on line.

After looking at the install, of this unit, I do not think it is correct. One lead out of the transformer connects to the selenoid and to a lead of the humidistat. The other lead of the tranformer connects to the other lead of the selenoid and the other lead of the tranformer. This appears to be a parrell install and I would think the selenoid would always be on. I think this shoud be in series?

Currently

Transformer Selenoid Humidistat
T1------------S1--------H1
T2 -----------S2--------H2


I think it should be

T1----S1 S2--------H1

T2---------------------H2


But with no install intstructions I am not sure. But to me it seems like the humidistat would be wired to break the circuit, but in this case, the tranformer was always connected to the selenoid. Hummm. Now I wonder if the selenoid is bad too.... I dont have a 24 AC source that I can think of to test the selenoid.

Thanks,
David Bach

[Sparks]

It must be humidifier week! The solenoid coil can be checked with a simple ohmmeter, it shouldn't be OL or extremely high resistance such as Megaohms or even kilo ohms. I don't know, 24 volts, low amps maybe 40-200 ohms, I don't have a calculator handy and I'm not that bright. The humidistat should 'break' the 24 v, you are correct. The 24v should come from the transformer (if used) then go to the humidistat (one wire in series with humidistat) then to the solenoid. One wire from the transformer should remain unbroken. Simple circuit, as discussed in another post, be sure that 24v is only supplied when the furnace is running. Some set-ups use a current transformer to sense when the inducer motor is running to accomplish this, some are wired from the control board or tapped from the pressure switch. You don't want to dump water when the furnace is off.

[davidbach]

Well an update. I thought about my outside sprinkler timers. They are 24 volt. I plugged one in , touched the leads to the selenoid and water flows, so I know the Selenoid is good. I am sure I need to wire the humidistat in series with the tranformer and the selenoid. I guess the only bad was that the humidifier was on 100% of the time. The tranformer 120 was connected to the humidifer lead on the furnace circuit board. So hopefully this did not run water when the AC was on.

[davidbach]

Thanks for the quick response. I was only gone about 30 minutes :). Well I will need to find a new tranformer. YEs, the tranformer was wired to the furnace ciruit board Humidifer lead and common lead. It probably ran any time the furnace did, but hopefully not the AC.

Thanks again for the confirmation.

[Sparks]

No problem, just make sure ya get the correct va (volt-amps) transformer. They're readily available, no reason to order online.