Humidifier only working part-time :-(

[davearonson]

I have a bypass humidifier that is not doing its job. Even when the control is set on 50%, the indoor humidity can be quite low. During the cold snap we had in December and January (I'm in Virginia), it was about 25%, verified by my dehumidifier (and a cheap little humidity indicator).

The humidifier is an Aprilaire 600, with the manual controller, installed sometime before I bought the house about a year and a half ago. The pad is not brand-new; I replaced it late in the season last winter, but IMHO that should be good enough, and I don't think that's the problem (read on). I don't recall how good a job it was doing last year, but it's more necessary this year for medical reasons. :-(

Water sometimes flows, enough to leave some going down its drain tube, so it's not a clog or a completely-failing solenoid. (I've also taken off and reattached the tubes, verifying an unclogged orifice, and there seems to be no inline strainer. It's very hard for me to tell, with the solenoid mounted in a very inconvenient spot, and the wires passing through nearby closed holders so it would be hard to take it down.) However, it's very hard for me to "catch" it flowing, by going to it when the blower is on -- when I go there, even shortly after the blower has just come on, it's rarely flowing.

If I turn the controller knob, I do get a click out of the controller at a consistent point, around where the other things indicate the humidity is. But I do not get any audible click, nor water flow, out of the solenoid, unless it was already open.

My main guess is that for some reason the solenoid is not being told to open often enough or long enough. Does that make sense to you? What else needs to be true, beyond the humidity being low and the thermostat asking for heat? Or might it be flaky, or partially clogged in a sporadic way? Or not the problem at all?

If it depends on the thermostat: I have a ritetemp 6022, and the set of wires coming into the top, and jumper settings, do seem to be correct for what we have, though I can't vouch for what's on the other end of each wire. At least it does seem to function correctly as a thermostat.

Other info on the solenoid: I think it says "23 WATTS", "24/60 VOLTS" (which I ass-u-me means 24V, 60Hz), "IDENT 02/11", "VALVE NO A2012-S118" (the first part of that was very unclear), and "ORIFICE 3/64". It's very hard to get a clear pic of the label, as it's facing up from a high mounting point. :-(

Any ideas what to try, either for diagnosis or repair? I am not handy with a voltmeter, though I think I have one somewhere.

Thank you very much!

 

[Reach4]

If I turn the controller knob, I do get a click out of it at a consistent point, around where the other things indicate the humidity is. But I do not get any audible click, nor water flow, out of the solenoid, unless it was already open.

Are you saying that you get a click out of the controller or the solenoid?

There is more than one way to wire that humidifier. When you are doing the knob turning, but not getting water, is the blower on? Can you tell your thermostat to turn the blower on continuously?

With the automatic digital control, there a way to have the humidifier start the blower even if the temperature is not high. http://docs.electronicaircleaners.com/aprilaire_600a_installation.pdf The manual control does not seem to have that option.

https://www.aprilaire.com/docs/defa...laire-humidifier-model-600m-owners-manual.pdf

 

[Sponsor]

 

[davearonson]

I meant I get a click out of the controller if I turn its knob (past the current humidity). There is no click from the solenoid, even if the blower is going (whether due to heating or telling the thermostat to keep it on). I suppose under the exact right conditions (whatever else is required for the solenoid to be told to open), there could be, but I have yet to discover them. That's kinda what I'm after.

I'll edit my post to make that clearer, and remove a few things I've since found are false. (Mainly, that "1 minute" thing seems to be for test mode with the automatic control, which I don't have!)

 

[Reach4]

I suppose under the exact right conditions (whatever else is required for the solenoid to be told to open), there could be, but I have yet to discover them.

From the diagram, there appears to be only 2 wires on the control involved in turning on the solenoid. If the two terminals with those wires have 24 vac between them, then the control is not requesting water. If the voltage is zero, the thing stopping you is elsewhere.

 

[Dana]

Indoor RH of 25% during cold snaps is a sign of pretty hefty outdoor air infiltration or extreme over-ventilation. The "right" solution is to tighten up the house, not run a humidifier.

Targeting 50% RH in winter is actively BAD for the house, since even the vapor-diffusion through interior latex paint would be enough to create mold conditions on cold wood sheathing at that humidity level, and active air leaks could have saturated moisture content in building materials along the exit path, or even liquid condensation, a common source of ceiling staining in upper floors with insulated but leaky attic floors.) Even 40% would be on the high side. If you absolutely need to actively humidify, hold the line at 35% during the coldest 10 weeks of winter. Air that is 35% RH @ 70F is a dew point of 41F, so only materials that are 41F or colder along the leak path would be taking on moisture.

Air that is 50% RH @ 70F has a dew point of about 50F, which in winter is almost every thing along the exfiltration paths, and even on clear-glass double pane windows when it's under 20F outdoors:

In the spring when it warms up to mold-growth temperatures in the damp building assemblies the mold spore count indoors can soar.

Air that is 50% RH is also on the high end of the human-healthy range too. Above that dust mites can have exponential reproduction rates. Most charts put 30-50% as the optimal for human health & comfort.

At the current IRC 2015 building code maximum leakage levels (3 air exchanges per hour at 50 pascals pressure) most homes need some amount active ventilation to keep the interior under 50% RH (and it's a good idea to actually run that ventilation to bring the RH down.) While it's possible to retrofit a an air leaky house to be that tight, it takes a bit of analysis and effort to get there. But it's not difficult at all to tighten up a house to where it would stay in the mid 30s for RH without active humidification.

Unbalanced heating ducts or air handlers & ducts in attics above the insulation can drive air infiltration rates stratospheric when running, and are a prime suspect when interior RH is as low as yours in a VA type climate.

If you're interested in fixing your air leak problems I can go into more detail on how to diagnose find and fix different aspects.

If your only goal is to just get the humidifier running, try to keep it under 40% until outdoor temps are averaging in the 40s F or higher. Buy a few $8-10 battery operated Accu-Rite humidity monitors and place them in a few locations in your house (skip the bathroom & kitchen, where there are acute humidity spikes) to get a sense of what your average indoor humidity levels really are. Brand name notwithstanding they're not super-accurate calibrated scientific instruments (and priced accordingly), but in the mid-ranges that matter they're good enough.

 

[Jadnashua]

IF you have a multimeter, it's fairly easy to figure out what's going on.

See if you have 24vac between the two leads going to the solenoid (it could be anywhere between about 22-32vac). If you do, and there's no water, one of two things is going on:
- the valve is not opening
- there is something plugging the water line

If you never get 24vac to the solenoid, it will never open. That could be the controller, the fan interlock, a broken wire, and probably some other things as well.

The solenoids do fail, but generally, are easy to replace and area available as a repair part.

 

[davearonson]

We are also working on tightening up the house. I suspect the downstairs floor leaks like crazy, pulling in air from the large crawlspace beneath, since it gets so much colder than the upstairs. (At least we have covered most of the crawlspace vents for the winter.) When the weather gets a bit warmer so I can stand to be down there for a while, I intend to go check where the insulation batts have fallen away and need to be shored up somehow. Meanwhile we're putting sealers in all the receptacles and switches on exterior walls, checking the weatherstripping, etc.

Further news:

• I have dug out the multimeter a roomie left behind decades ago, and verified that the humidistat is good. (Assuming I'm using it right, which I'm not at all sure of!)

• Another problem could be that the humidistat is mounted on the air return, downstream of where the humidifier connects to that. So, as soon as the humidifier starts humidifying the air, the humidistat will probably just shut it right off! (Don't get me started on all the idiotic things wrong with this house.) So, I'm going to try removing it from there, covering up the hole, and seeing what happens. If that works decently, I will try extending the wire and poking it through the wall so I can just mount it next to the thermostat.

 

[Dana]

In a VA climate a vented crawlspace makes no sense- venting puts more moisture into the floor joists & subfloor during the summer months than it extracts. A sealed crawlspace with a ground vapor barrier sealed to the foundation walls, insulated with R10 continuous insulation is the way to go. Air-sealing the walls, foundation sill and band joist is easier and more reliable than working on air sealing at the subfloor, especially if it has duct, electrical & plumbing penetrations. Insulating & air sealing at the foundation walls puts the structural wood fully inside of conditioned space where it stays dry and mold-free.

If you're planning to live there for awhile, converting it to an sealed-conditioned crawlspace is going to be worth it, on both comfort and heating/cooling energy use grounds. A vented crawlspace under a leaky subfloor is like leaving a window open in summer, raising the latent cooling load considerably!

Insulation between the joists is not a substitute for air sealing the subfloor. Fiberglass does very little to slow down the air flow, and facers on batts are virtually impossible to air seal even for the short term, let alone for decades.

The band joist & foundation sill seam leaks add up to more than all of the window & door crackage leaks combined in a typical house that hasn't undergone a round of air sealing. Wall socket & electrical box leaks are pretty small by comparison.

Not all air leaks are of equal importance. Those at the top of the house, and the bottom of the house dominate, because that defines the total 24/365 stack effect infiltration drive. If there are air handlers & ducts in the attic, above the top floor ceiling and insulation it can be difficult (but not impossible to air seal both the ducts and the penetrations. Ceiling lighting fixtures (especially recessed cans), flue & plumbing stack penetrations can easily add up to several square feet of air leak. Less obvious (and even worse) are partition walls or balloon framing that have no top-plates. Open hearth fireplaces with a damper in the firebox tend to leak large amounts of air. A gasketed chimney top type damper works much better, but still isn't perfect. Chimney chases are also huge air leaks, ideally air sealed (with metal flashing) where ever it passes through a floor or ceiling.

There's a lot of poking around and fixing the obvious to do before hiring a pro with an infra-red camera and blower door to nail the rest of the big leaks. But start at both the top of the house and bottom of the house to lower the stack effect drive. The air leaks in the middle matter a whole lot less than leaks the subfloor over the crawlspace, and the ceiling below the attic.