Solenoid Valve - Humidifier

[Jason Kay]

Hello.

I just replaced the solenoid valve (1099-46) on my whole house humidifier (pic attached). Water wasn't flowing, so I replaced the valve and now it flows. However, it doesn't seem to want to shut off. The only time it stops flowing is if if cut power to the valve or I turn off the humidistat. Even when the system is shut off (but still has power), the valve stays open and water keeps flowing. It's only closing when power is cut or humidistat is set to "off".

Is it a faulty humidistat causing the issue? It's about 13 years old. The valve appears to work just fine. Any suggestions? Thank you.

 

[Stuff]

Are you sure that you didn't change the wiring with the new valve? If it is a standard two wire humidistat one wire of the valve goes to the transformer (or furnace) and one to the humidistat.

 

[Sponsor]

 

[Jason Kay]

Don’t think so. Atttached is the wiring before I replaced the valve. Wiring is the same after I replaced it.

 

[Stuff]

That looks fine (and simple). So your idea of a bad humidistat is valid. See what happens if you remove one wire from the humidistat. I assume there are only two wires going to it.

 

[Dana]

As a general rule active humidifiers are a band-aid for wintertime dry air in houses that are too leaky or being actively overventilated by poorly designed or poorly controlled ventilation schemes. (Does your furnace system take in outdoor ventilaion air?) The better solution to dry wintertime air is usually to air-seal the house better, and/or throttle back the ventilation rates in winter. One doesn't even have to be as air-tight as 3ACH/50 (air exchanges per hour @ 50 pascals, the current code-maximum for new construction) to keep indoor RH above 30%, at the low end of the "comfortable and healthy zone".

The risk of active humidifiers is higher moisture content in the building materials when over-humidified, yielding much higher mold spore counts in the indoor air in spring, when the exterior walls & ceiling temperatures rise high enough to support rapid mold growth. To avoid those issues in a climate as cool as West Orange one should hold the line at <40%RH @ 70F in winter (keeping it 30-35% is better).

If you keep it ~50% RH all winter there is a risk of structural rot taking hold in wood sheathed wood framed houses, so even though it's a healthy and comfortable level for humans, it's not good for the house, and not good for springtime indoor air quality.

 

[Stuff]

As a general rule active humidifiers are a band-aid for wintertime dry air in houses that are too leaky or being actively overventilated by poorly designed or poorly controlled ventilation schemes.

Good point. Most of the time we just throw a solution at the symptoms rather than fix the root of the problem.

 

[WorthFlorida]

This is just a thought.
Was the thermostat changed in the past year? What might have happen was the old valve wasn't working because of a broken wire or open solenoid and changing the thermostat (a miss wiring) or the humidistat, the bad solenoid wasn't noticed until this heating season.

 

[Jason Kay]

Thanks. I replaced the humidistat and I'm having the same issue. When the thermostat is off (or set below room temp), the humidistat will open the valve when set to, say 50% RH, even though the system isn't calling for heat. The only way to turn it off is to set the humidistat to "off". So, basically, calling for heat isn't triggering the valve to open or close. Only changing the dial on the humidistat shuts it off or turns it on.

 

[Stuff]

Next stage of troubleshooting: What brand/model of humidifier? Most have a float switch/valve wired in.
Also for some installations the humidifier is wired to the furnace so that it only runs when heat is activated.

 

[Cacher_Chick]

I think it is time to see the wiring diagram for the furnace to determine if the humidifier is connected as per the mfg. instructions. It may be that there is a failed relay on the control board.

 

[Reach4]

When the thermostat is off (or set below room temp), the humidistat will open the valve when set to, say 50% RH, even though the system isn't calling for heat. The only way to turn it off is to set the humidistat to "off". So, basically, calling for heat isn't triggering the valve to open or close. Only changing the dial on the humidistat shuts it off or turns it on.

If you have a Blower Activation switch, turn that off. It may be on the bottom of the control.

 

[Jason Kay]

This is the humidistat.

 

[Reach4]

This is the humidistat.

http://www.generalfilters.com/literature---faq/installation--owners-manuals.html has manuals on various legacy units.

If you look at the wiring diagram, some hookups show a current sensing relay or air pressure switch. Maybe your sensor failed.

 

[Jadnashua]

You need a working interlock control to prevent the humidifier from running when the furnace's fan is not running, or if the humidity is below the humidistat's setting, the valve will just stay open. As mentioned, that might be a current sensing relay on the fan, an air vane switch to indicate the air is moving, or if your HVAC system contains the logic, proper hookup to the HVAC system.

 

[WorthFlorida]

This has a simple wiring diagram but do note that the humidistat is wired to the furnace control board marked C and HUM. As suggested above by a few the humidistat should only get power when heat is called for.

https://diy.stackexchange.com/quest...nnect-my-whole-house-humidifier-to-my-furnace

 

[Jason Kay]

Just getting back to this. Attach is the wiring. Not sure if this helps but I’m not sure what the next steps are. Not familiar with some of the terms and suggestion others provided. Thanks!

 

[Reach4]

Humidifiers vary. My bypass pad unit is controlled by the W terminal and also connects to the C terminal. So when there is a call for heat, the solenoid runs. There is provision to control it with the G (fan) control, but I think W is better for my type.

How are you supposed to connect yours? I posted a link to some humidifiers of your brand, but you did not identify yours. Too hard?

 

[Jason Kay]

Model:

 

[Reach4]

Model:

That is not your humidifier.

If you cannot identify the documentation, I think you might be better off replacing the humidifier rather than trying to fix this one.

 

[Dana]

That's a 4-ton air conditioning coil, not a humidifier. (Four tons of AC is a lot for a NJ location, or even the Gulf Coast- is this a 5000 square foot house or something?)