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Question : My Generalaire Model 1042LH Humidifier not working

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  • Dec 14th, 2020 1:36 pm
[OP]
Jr. Member
May 1, 2004
135 posts
27 upvotes
Toronto

Question : My Generalaire Model 1042LH Humidifier not working

Hello everyone,

Could anyone provide me an advice what is the problem and how to fix my Generalaire Humidifier?
My whole house Humidifier is not running, it seem the water is not come out from the valve.
I went thru some youtube video to test the voltage but cannot confirm the actual problem. Is the SOLENOID VALVE dead or need replacement?

The meter show very low number and then down to zero. (see image attachement)

Please suggest.
Thanks
cs
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13 replies
Deal Expert
User avatar
Jun 12, 2007
16130 posts
4954 upvotes
London
Looks like no volts at the solenoid.

Is the humidistat set to x% ? Rotate the setting to full on and check the volts again

Note - Water only runs during certain phases of the furnace running.
Deal Guru
User avatar
Feb 23, 2008
12293 posts
1170 upvotes
Brampton
Do you hear any noise from the solenoid? Mine makes a loud click when the valve opens.
Lets Go Blue Jays!!!
[OP]
Jr. Member
May 1, 2004
135 posts
27 upvotes
Toronto
cheapmeister wrote: Do you hear any noise from the solenoid? Mine makes a loud click when the valve opens.
I turned on to Comfort Max setting, but I did not hear any noise from the solenoid valve when the furance starting.
Deal Guru
User avatar
Feb 23, 2008
12293 posts
1170 upvotes
Brampton
cs942008 wrote: I turned on to Comfort Max setting, but I did not hear any noise from the solenoid valve when the furance starting.
Comfort max? Is this the highest setting the dial will turn?
Lets Go Blue Jays!!!
Deal Addict
May 9, 2003
1636 posts
853 upvotes
I recently helped a friend with the same issue.

Easiest way to figure out if it's the selnoid...

1) Turn humidstat to on. No water?
2) Cut power to furnace.
3) Unscrew water supply line to Selnoid. Turn on water supply. There should be water flowing. (Rules out clogs).
4) Unscrew water supply line from Selnoid to unit.
5) Replace Selnoid
6) reinstall too water lines.
7) Turn power on
8) Turn water on
9) Turn humidstat on
10) Should work!
[OP]
Jr. Member
May 1, 2004
135 posts
27 upvotes
Toronto
bizzyseller wrote: I recently helped a friend with the same issue.

Easiest way to figure out if it's the selnoid...

1) Turn humidstat to on. No water?
2) Cut power to furnace.
3) Unscrew water supply line to Selnoid. Turn on water supply. There should be water flowing. (Rules out clogs).
4) Unscrew water supply line from Selnoid to unit.
5) Replace Selnoid
6) reinstall too water lines.
7) Turn power on
8) Turn water on
9) Turn humidstat on
10) Should work!
Thanks for you info. Just wonder anybody know where can I buy the solenoid valve in GTA and Markham?
I guess the parts I am looking for SOLENOID VALVE ASSEMBLY 990-53

Any suggestions.
Thanks
Deal Addict
Jun 16, 2009
2566 posts
952 upvotes
Woodbridge
https://www.amresupply.com/part/GF-990- ... noid-valve

Address : 2161 Midland Ave. Scarborough, ON, M1P 4T3
cs942008 wrote: Thanks for you info. Just wonder anybody know where can I buy the solenoid valve in GTA and Markham?
I guess the parts I am looking for SOLENOID VALVE ASSEMBLY 990-53

Any suggestions.
Thanks
HVAC Professional. Committed to customer, not brand.
Central Air Condition Group Buy-2021
Deal Expert
User avatar
Jun 12, 2007
16130 posts
4954 upvotes
London
But OP is only getting 1.9 volts on the solenoid ? Shouldn't he be seeing 24V ?
[OP]
Jr. Member
May 1, 2004
135 posts
27 upvotes
Toronto
l69norm wrote: But OP is only getting 1.9 volts on the solenoid ? Shouldn't he be seeing 24V ?
When the furance running, I got 1.9 volts and then dropped back to zero.
I am going to replace the solenoid valve. Hope it work.

Thanks
Newbie
Jan 13, 2006
97 posts
40 upvotes
Markham
I had a similar problem where the water wasn't passing through the solenoid. I picked up a new solenoid and after about 1.5 years, I ran into the same problem. I bought another, but decided to play around with the very first one I had. Turns out there was mineral deposits which clogged the hole going to the output port so that water would go into the solenoid, but would not go into the humidifier unit. I disassembled the solenoid and used some CLR (or similar cleaner). Left it for 30 mins, then rinsed the solenoid out.

If you disassemble the solenoid, and run water through the output port (not input port), you will see no water coming out. After using CLR, when you run water through the output, you will see a thin stream of water coming out of the hole in the center.

From the attached image, the left side of the solenoid is the input side, and the right is the output side. The way it works is that water from your line goes into the solenoid through the input port. You can see there is a mesh filter to filter small particles. Once the water goes in it will come out in the small offset hole around the 8:00 position. The plunger (inside the silver cylinder part) is held down to prevent water from exiting. When the furnace comes on and the 24v is sent to the solenoid, the electromagnet pulls the plunger up and water goes thought the small hole in the center and to the output port into the humidifier. If you run water from the output port before using the CLR, you may notice that water does not stream out the center hole. If no water streams out, then you have a clog. Use CLR and after it has had time to do its work, pour water through the output port and see if a stream of water comes out of the center hole. If it does, you just saved yourself from buying a new solenoid.

If your solenoid is actually not getting the 24v, then you need to replace it. I checked mine by setting the humidstat to it's max value, and setting the thermostat to some high amount like 30c. This should send the full 24v to the solenoid and I verified I was getting the required voltage. Without the right voltage, the electromagnet won't be strong enough to lift the plunger to allow the water to flow to the humidifer.
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[OP]
Jr. Member
May 1, 2004
135 posts
27 upvotes
Toronto
Thanks Everyone.

I bought a new solenoid valve and fixed the problem.

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