Troubleshooting my Humidifier - Advice Solicited

Jaybird180

Jaybird180

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Jaybird180
I had a whole house humidifier installed a few years ago (2010 or 2011) and have not been satisfied with the performance since installation. It's an Aprilaire 600 bypass type and everything I've read on it suggests that its a good unit with a simple design. I think the problem is the installation, and for several reasons some of which I'll dispense with.

My latest theory is that it's the 6" supply duct (hot air) is not supplying positive pressure. The bypass unit requires a pressure differential to allow air to move over the filter unit and exit the return side and then into the furnace thereby adding humidity to the air.

The installation in my basement is very confining, which possibly explains why the installer did things the way he did. I have an HVAC guy I'm consulting with to help find a solution, but he's got a lot of other clients who's jobs are probably simpler.

I think I can test my theory by putting something over the duct and see if it is blowing, as I don't want or think I should invest in a static pressure gauge, just to test a theory.

If it pans out, I'm a bit lost on solutions. I thought of building out the duct to create a larger air chamber and then the air-pressure in the 6" duct should increase, according to my understanding of air pressure in closed systems.

Comments, suggestions, holes in my theory or implementation?
 
I have an AprilAire, too. Dunno the model number.

I'm trying to visualize it now - it's mounted on the cold air return, with a duct that comes from a hot air plenum. So the hot-air side would be a higher pressure since it's down stream of the blower. That means that hot air moves across the wet pad, into the cold air side, and puts humidity into the cold air going into the furnace.

A couple of things:

1) The hot air duct (on my system) that feeds into the humidifier does have a gate that I can open and close - I have it marked Summer/Winter so I know where to turn it to open or close it when I need to. If it's closed for summer, no air will move from the now air-conditioned side back through the humidifier.

2) The humidifier (my system) is fed by a line that is attached to a water line (I think it's a hot water line, right out of the water heater) by a saddle valve. Make sure that works, open and close that valve a couple times to make sure it hasn't crusted shut because of hard water deposits. You can check this by removing the hose where it goes into the top of the humidifier and watching for a dribble of water when the furnace fan turns on and opens the solenoid in the humidifier.

3) The filter pad might be clogged. It is designed to catch as much water as possible from above and spread it out over a large surface area. If you have hard water, deposits will eventually form and clog it up. Replace it with a new one - the last time I did the old one weighed considerably more than the new one.
 
A ) Were you satisfied with what you had before?

B ) How old / how tight is the house?
 
Let me add 2(a):

In the water line, I can't remember if it's on the inbound or outbound side of the solenoid valve, there will be an orifice that chokes down the water pressure. If that is clogged, you might not get any water flow, or you'll only get a very small amount. Be careful if you disassemble this thing, there are a couple of small parts that might surprise you.


--
My troubleshooting normally begins with the water flow. If you see a lot of water draining out the bottom, you are good. After that, it's air flow. If you have decent flow from the high pressure side (there isn't a baffle that's closed) and there's nothing blocking the low pressure side, then replace the pad.

Theory of operation on these things is pretty simple.
 
The water element requires replacement once a year. It'll be covered with mineral deposits and very inefficient. If the minerals get bad enough the water will shut off. If you can't evaporate water there's no need to feed it water, right? The humidity transfer won't work worth squat with even a partially clogged element. There's a butterfly valve in the forced air intake duct. When the blower is on there's no mistaking the heated air flow through it. Make sure that's open. After you change the water element and clean out the minerals you'll need to re-set the unit. If memory serves you rotate the adjust dial all the way clockwise for a few seconds and it'll reset.
 
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Jaybird180 said:
I had a whole house humidifier installed a few years ago (2010 or 2011) and have not been satisfied with the performance since installation. It's an Aprilaire 600 bypass type and everything I've read on it suggests that its a good unit with a simple design. I think the problem is the installation, and for several reasons some of which I'll dispense with.

My latest theory is that it's the 6" supply duct (hot air) is not supplying positive pressure. The bypass unit requires a pressure differential to allow air to move over the filter unit and exit the return side and then into the furnace thereby adding humidity to the air.

The installation in my basement is very confining, which possibly explains why the installer did things the way he did. I have an HVAC guy I'm consulting with to help find a solution, but he's got a lot of other clients who's jobs are probably simpler.

I think I can test my theory by putting something over the duct and see if it is blowing, as I don't want or think I should invest in a static pressure gauge, just to test a theory.

If it pans out, I'm a bit lost on solutions. I thought of building out the duct to create a larger air chamber and then the air-pressure in the 6" duct should increase, according to my understanding of air pressure in closed systems.

Comments, suggestions, holes in my theory or implementation?
Click to expand...

Maybe I am not picturing this correctly,, but...

Taking high pressure , heated air bleed air that is downstream of the furnace, circulating it back through the filter / humidifier element and then reheating it all over again seems fruitless since the heating process will remove the added humidity,,:confused::confused::confused::confused:
 
N801BH said:
Maybe I am not picturing this correctly,, but...

Taking high pressure , heated air bleed air that is downstream of the furnace, circulating it back through the filter / humidifier element and then reheating it all over again seems fruitless since the heating process will remove the added humidity,,:confused::confused::confused::confused:
Click to expand...

I'm about to go down into my basement and check the airflow, but mine is mounted on the cold air side. This is from the Aprilaire website:

Aprilaire bypass humidifier’s get there air movement through the Water Panel® by the differential pressure between the supply (hot air) plenum and the return (cold air) duct. The supply plenum is under positive pressure and the return duct is under negative pressure. One of the advantages of a bypass humidifier is that it can be installed either on the supply plenum or on the return duct with equal effectiveness. No matter which duct the humidifier is mounted on, the airflow always goes from the supply to the return through the humidifier. A bypass humidifier will also have no adverse effect on any component in the furnace, air cleaner or filter. Aprilaire® Humidifiers put “water vapor” into the air, not raw water. This is nature’s way of getting relative humidity into the air.
 
N801BH said:
Maybe I am not picturing this correctly,, but...

Taking high pressure , heated air bleed air that is downstream of the furnace, circulating it back through the filter / humidifier element and then reheating it all over again seems fruitless since the heating process will remove the added humidity,,:confused::confused::confused::confused:
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Heating cool moist air will not remove the water vapor. This is a pretty typical way for humidifiers to work.
 
Yep, just verified. Exactly what happens. Hot bleed air moves across the evaporator pad back into the cold air return side, and that humidified air goes back across the heat exchanger.
 
To answer a few things asked.

It's an Aprilaire model 600 and it did not replace anything. I am not having a water problem, in fact I am wasting a lot of water as though the unit does nothing but provide a conduit for bleeding water out the drain, hence my latest theory.

Pic in next post
 
Matt described the operation very well in post 2
 

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When was the last time you cleaned it?

Replaced or cleaned the filter?

Pull the feed tube out of the top while it is running and see if the water is running. Then pull the top cover and see of the water is being distributed across the top (unit is perfectly level) so the water drains down across the entire media.

The latest installation from Aprilaire guilds say hook it up to hot water, NOT cold water. It helps with the evaporation.

From there it is air flow through the unit. The high pressure side (fan side) should be enough pressure to feed the return air side (suction side). Take the duct off and see if warm air is flowing out the supply side (to the humidifier)
 
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Matthew said:
It's a 'closed' recirc system, not the combustion air.
Click to expand...


So... Buildings are sealed up tight to prevent cold air infiltration in the winter and all the humidity created in those structures ,ie ( showers, breathing, cooking, sweating etc etc)... is trapped and will release moisture into that closed and sealed space/area..... In reality, a building should need a de-humidifier to get rid of the excess moisture.....

Anyone care to guess what removes all that moisture and causes the need to humidify the inside air ??:dunno:........:rolleyes:
 
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A lot of water can mean a clogged pad, and the water just runs right off.

Also check - where the water runs out of the feed line, it lands in a shallow tray with drain holes along the length of the tray. That distributes the water along the top edge of the pad. If any of those holes are clogged, water could be running over the edge and not through the thickness of the pad.

Hard water and mineral deposits can mess with humidifiers.
 
N801BH said:
So... Building are sealed up tight to prevent cold air infiltration in the winter and all the humidity created in those structures ,ie ( showers, breathing, cooking, sweating etc etc)... is trapped and will release moisture into that closed and sealed space/area..... In reality, a building should need a de-humidifier to get rid of the excess moisture.....

Anyone care to guess what removes all that moisture and causes the need to humidify the inside air ??:dunno:........:rolleyes:
Click to expand...

No, the house exchanges air. IIRC I read something about a normal exchange being 4x per day
 
Matthew said:
A lot of water can mean a clogged pad, and the water just runs right off.

Also check - where the water runs out of the feed line, it lands in a shallow tray with drain holes along the length of the tray. That distributes the water along the top edge of the pad. If any of those holes are clogged, water could be running over the edge and not through the thickness of the pad.

Hard water and mineral deposits can mess with humidifiers.
Click to expand...

What he said! :lol:
 
N801BH said:
So... Building are sealed up tight to prevent cold air infiltration in the winter and all the humidity created in those structures ,ie ( showers, breathing, cooking, sweating etc etc)... is trapped and will release moisture into that closed and sealed space/area..... In reality, a building should need a de-humidifier to get rid of the excess moisture.....

Anyone care to guess what removes all that moisture and causes the need to humidify the inside air ??:dunno:........:rolleyes:
Click to expand...

The air going through the furnace goes from the intake low pressure side, gets humidified by bleed air, then gets pushed across the heat exchanger. The humidity doesn't get removed. I did put 'closed' in quotes. The furnace and water heater use air for combustion and THAT humidity goes up the flue. Any time you open a door you'll pull in outside air and it'll seep in anywhere else it can.
 
Geico266 said:
When was the last time you cleaned it?

Replaced or cleaned the filter?

Pull the feed tube out of the top while it is running and see if the water is running. Then pull the top cover and see of the water is being distributed across the top (unit is perfectly level) so the water drains down across the entire media.

The latest installation from Aprilaire guilds say hook it up to hot water, NOT cold water. It helps with the evaporation.

From there it is air flow through the unit. The high pressure side (fan side) should be enough pressure to feed the return air side (suction side). Take the duct off and see if warm air is flowing out the supply side (to the humidifier)
Click to expand...

I had the unit disconnected for a couple of reasons, but intend to have it reconnected and when I do, I was it to do more that run up my water bill and flood my backyard (drain flows into the sump).

The original installation was on the cold side. My reading their site back in 2011 and I had them come back out and change it. They came to my house 4 times to try and get results until they blew up my furnace circuit board and that's when I had it disabled and quit asking for their "help", although they were the "authorized dealer" who sold it to me.

The test you mentioned is the same I have in mind, to check the air flow.
 
Matthew said:
A lot of water can mean a clogged pad, and the water just runs right off.

Also check - where the water runs out of the feed line, it lands in a shallow tray with drain holes along the length of the tray. That distributes the water along the top edge of the pad. If any of those holes are clogged, water could be running over the edge and not through the thickness of the pad.

Hard water and mineral deposits can mess with humidifiers.
Click to expand...

I intend to have a whole house water filter installed to help with this condition, also I will take your advice about the shallow pan, I've seen it and didn't check if it's level, but by eyeball it looks about right.
 
Combustion air does not mix with the supply / recirculating air. If it did you would be dead.
 
Stewartb said:
Jaybird, FYI..... http://www.aprilaire.com/docs/defau...midifier-model-600-owners-manual.pdf?sfvrsn=6

I just did my own element change a couple of weeks ago because my heating guy was there for another issue and embarrassed me by opening the humidifier. Mine works great now. Next year I'll have forgotten all about it. Again. :)
Click to expand...

Thanks for reminding me. I have a grippe with the way they connected the humidistat and they also didn't install an outside temperature sensor, citing difficult installation (basement :dunno:). I'm still scratching my head on that one.
 
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The combustion chamber is separate from the conditioned air. The combustion chamber will suck up room air from approx floor level, burn the gas on one side of the exchanger, and exhaust up the flue. The forced air will be blown over the other side of the exchanger. You'll end up with a CO headache, or dead, if there is a crack in the exchanger.

Whatever humidity is in the combustion air will be lost.
 
Did a post disappear? I thought I was responding to someone else. huh...dunno
 
Looks like it is installed correctly on the furnace, I assume it is attached to the intake plenum and the pipe routes from the heated air side.

I would start simple. Check to make sure the control is set correctly. Since you don't have the outdoor sensor it should be set in the manual mode. Also make sure it is not in the test mode. Once you confirm this is working correctly I'd do the PM. They are simple devices and you should be able to make your walls sweat with it. I think your installer was lazy not putting the outdoor sensor in.

You should also check your air exchanger, make sure it is working correctly. It would be taking low humidity air from outdoors and sending your humidified air outside. It could be running at too high a rate, or possibly the humidifier can't keep up with four changes a day.
 
That ductwork doesn't look properly installed to me. Those joints don't look like they are sealed correctly. I know this isn't the problem, but you don't want to have moist air flowing into unconditioned space.
 
I just looked back and noticed you posted a pic. Like Alex said, you can tape the seams, and that will help a little, but otherwise I don't see anything obvious to me. It looks like my installation, I'll post a picture soon. I can't tell very well from the picture, but if you are not getting a good pressure gradient the system might not work very well. Is the hot air duct coming out of the air handler as close it can get to the blower or is it attached along a duct that was convenient?

Mine was able to be installed on the cold air return just before the furnace intake and the hot air duct comes out right above where the a/c coil sits.

If you pop open the cover, place a piece of cardboard over the pad and let a kleenex or rag hang in front of the hot air duct to verify airflow direction. then put out the pad and repeat at the other side. If airflow goes from the hot air side to the cold air side then the only thing left would be the volume of that flow. The water valve should only open when the blower turns on. The thermostat will open the gas valve, the igniter will light the flame, the exchanger will heat up, the blower might go to a low speed for a few seconds, then lower will turn on full speed and the same signal will open the water valve. If you are seeing a lot of water, is the valve not closing?
 
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Matthew said:
I just looked back and noticed you posted a pic. Like Alex said, you can tape the seams, and that will help a little, but otherwise I don't see anything obvious to me. It looks like my installation, I'll post a picture soon. I can't tell very well from the picture, but if you are not getting a good pressure gradient the system might not work very well. Is the hot air duct coming out of the air handler as close it can get to the blower or is it attached along a duct that was convenient?
Click to expand...

The seams should be coated with mastic.Look at the water line, come on man, why not just drag a water hose up there. My concern looking at that install is it isn't good work and that probably means there are other things incorrect we can't see. I would take a good look at all of it.
 
Alexb2000 said:
The seams should be coated with mastic.Look at the water line, come on man, why not just drag a water hose up there. My concern looking at that install is it isn't good work and that probably means there are other things incorrect we can't see. I would take a good look at all of it.
Click to expand...

Good point, maybe they didn't cut a hole in the plenum.......
 
PaulS said:
You should also check your air exchanger, make sure it is working correctly. It would be taking low humidity air from outdoors and sending your humidified air outside. It could be running at too high a rate, or possibly the humidifier can't keep up with four changes a day.
Click to expand...
Okay. Where would I find that?
Alexb2000 said:
That ductwork doesn't look properly installed to me. Those joints don't look like they are sealed correctly. I know this isn't the problem, but you don't want to have moist air flowing into unconditioned space.
Click to expand...
I think I will have the new contractor do that as best we can. I'm finding several things the homebuilder did to save space or materials that I would have done differently.
Matthew said:
I just looked back and noticed you posted a pic. Like Alex said, you can tape the seams, and that will help a little, but otherwise I don't see anything obvious to me. It looks like my installation, I'll post a picture soon. I can't tell very well from the picture, but if you are not getting a good pressure gradient the system might not work very well. Is the hot air duct coming out of the air handler as close it can get to the blower or is it attached along a duct that was convenient?
Click to expand...
A little of both. The original install is quite compact and there are many ducts that I cannot see. I've never been able to get an engineering drawing for my house. The builder declared bankruptcy and then reopened in another name. They didn't retain old documents. One of these days, I'm going to see if the county retains them on file and pay whatever I need to get the drawings if they have them. I think they will be of some value to help answer break-fix or upgrade questions.
 
I'm glad to see so many people using the AprilAire 600. I've been tinkering with the idea of getting one for several weeks now - our house is DRY this year.

From the responses here, I'm assuming that it works well and, other than Jaybird, it is working well for everyone.
 
Alexb2000 said:
The seams should be coated with mastic.Look at the water line, come on man, why not just drag a water hose up there. My concern looking at that install is it isn't good work and that probably means there are other things incorrect we can't see. I would take a good look at all of it.
Click to expand...
That large diameter clear hose is the drain hose coming out the bottom.

Here's my installation.

Yeah, I can do a little work on the seams, too, but when I checked the last time I couldn't feel any air leaks.

The humidistat is mounted above the humidifier - I don't have a fancy one, mine is a much older model. Just downstream of that is the humidifier itself. Below that, out of the picture is a 90deg bend that holds the furnace filter. To the right of that bend is the furnace intake. Then there is the furnace itself, above that (in the photo) is the A/C coil, and above that is where the hot air comes out and feeds back across the evaporator pad. You can see the handle on the flap that I can open/close for winter and summer use. In the summer, I close that valve so conditioned air goes out to the house and doesn't bleed back into the intake.

You can see the copper water line (looks like an icemaker line) below the unit, just to the left of the drain. Inside the cover there is a plastic feed line that carries water from the opposite side of the valve and drips it on the top edge of the pad.
 

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The install may not be perfectly tidy but it isn't horrible. The water line and drain line look fine. The ducting appears correct. I have a digital control but it's got a jumper installed to make to run manually. No outside air temp sensor. I dial my relative humidity to whatever's appropriate for the season and it works fine, as long as the evaporator is clean. If a guy has a clean system and follows the simple instructions for verifying water flow there's very little that can go wrong. Pop the front off the unit and call for heat and you'll know instantly whether you have air flow. The highest likelihood for trouble is a clogged evaporator panel or a fault in the control settings. These units have status lights and troubleshooting instructions. If you can't make it work with that? Wait for the HVAC tech. After all, it isn't a 911 emergency. It's just a humidifier.
 
Jaybird180 said:
Okay. Where would I find that?

I think I will have the new contractor do that as best we can. I'm finding several things the homebuilder did to save space or materials that I would have done differently.

A little of both. The original install is quite compact and there are many ducts that I cannot see. I've never been able to get an engineering drawing for my house. The builder declared bankruptcy and then reopened in another name. They didn't retain old documents. One of these days, I'm going to see if the county retains them on file and pay whatever I need to get the drawings if they have them. I think they will be of some value to help answer break-fix or upgrade questions.
Click to expand...

Where would you find that...... good question. I would start by looking for a fresh air intake that isn't connected to the burner side of your heater. You may or may not have this.

I looked at your set up and from the angle it's a little hard to see, but are you sure the humidifier connects from the hot air side to the cold air side of the furnace? If not it won't work.
 
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