Aprilaire 700 - Not Raising Humidity

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Old 12-06-06, 10:21 AM
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Aprilaire 700 - Not Raising Humidity

I have just installed an Aprilaire 700 humidifier a few months ago and I can't seem to get my humidity over 22-23% (no condensation on the windows!). Ideally, I would like to see it around 35%.

I have the humidifier installed on the supply, the humidistat installed on the return. The humidifier is hooked up to hot water as well. As the furnace is running, there is no place on the dial where I can hear it go on. It does work in the Test mode fine for about a minute.

I have had the humidistat replaced once because I thought it was bad. One thing I did notice was when power was applied to the humidistat each time the furnace goes on, the red and green light flashed momentarily then went off, then sometimes the humidifer would run (the dial setting is at the max, my humidity level in the house is in the mid 20's). The instructions did say this would happen when power is first applied, so I'm thinking that this is not an issue since power is going on/off to it.

Anyway, can I increase the humidity anyway? Is it possible I have another bad humidistat? Or am I just expecting too much out of this humidifer?

thanks for all your help.
 
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Old 12-24-06, 09:32 PM
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Opinion I heard from HVAC serviceman

I just had my heat pump winter PM done, and the serviceman told me to watch out for problems with my Aprilaire 600 not working. Seems like he had a lot of calls with this problem, which traces to the outdoor sensor malfunctioning. The outdoor sensor is a simple thermal resistor, which varies resistance with outdoor temperature to adjust the set point of the humidistat. They can short out, burn out, get wet, or in some other way malfunction.

He suggested I hold on to the "manual" adapter which was included with my humidifier kit, but is typically discarded by the pros if you have it installed. It is basically a fixed resistor. When you install it in place of the outdoor sensor, it makes the humidistat into a manual unit, with no adjustment of the humidity based on the outdoor temp.

If you still have the Aprilaire manual adapter, try that out and see if your humidifier starts to work.
 
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Old 01-01-07, 03:21 PM
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Furnace run time is going to play a major role in how well the humidifier works. If you have an over size furnace that could be part of the problem. I like the controller to be powered at all times using a current sensing relay and transformer that is suppied with humidifier vs. it powering up every time furnace kicks on. Relay is not supplied with humidifier.
 
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Old 01-02-07, 09:36 AM
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Thanks for the input.

I agree with the furnace run time. I am thinking about powering the humidistat up via the EAC terminals, that way I can just run the fan to get more humidity rather than rely on the heat call to the furnace. The only problem I see is that if the h-stat isn't calling for more humidity it will do no good.

My Carrier board has EAC-1 and EAC-2. Is one of these hot and the other neutral??

As far as the outdoor temp sensor is concerned, I took an ohm meter to measure the resistance as they suggest in the intall manual, and it seemed to be reasonable.

Here is St. Louis though the weather has been crazy, 60 degrees one day, 20's the next so that may be a part of the problem as well.

Steve
 
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Old 01-02-07, 01:27 PM
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There are so many variables-long list for sure. Yeah, warm weather makes em go whacky. Thats why I go manual on them. Just have to be careful during a long cold spell. Also are you sure your hygometer is right.
 
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Old 01-02-07, 03:15 PM
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I am not sure if my hydrometer is accurate or not. In fact, I have 2 of them (digital) that are the same make/model and set them side by side. They were off one another by 5%! So perhaps they are not accurate???

Is there an accurate way to measure humididy? I do notice some condensation on the windows on some (cold) days, it just is about 1" of moisture on the bottom of some windows. I think I am getting some proper humidity based on that and I am not shocking my self on door knobs and have yet to wake up with a dry, scratcy throat.
 
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Old 01-02-07, 04:18 PM
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You may not be as far off as you think. For fun you can make your own sling psychrometer and ckeck it against the electronic ones you have. You have to buy expensive hand helds to really get accurate. Some still use the sling and are just as accurate. Do a search on the web.
 
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Old 01-10-07, 11:46 PM
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Steve123 First take that D** O T sensor off . Put the manual mode case on the control. Do you hear the fan on and the solenoid is warm when the furnace is on?? Some water comeing out the drain pipe????
I see you said St Louis Im at Lake of the ozarks I just set the humidity control and let it alone. like you said the temp just goes up and down so it will all work out .
 
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Old 01-11-07, 01:41 PM
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I did try the manual mode (a while ago), didn't seem to make much difference. There seems to be no place where I can hear the click on the solonoid as I turn the dial. I think the humididty level must be satisfied.

I do hear it run in the morning, I can actually hear the fan thru the ducts. It seems to come on after the furnace has run a few minutes, that seems odd to me. Maybe because the air is circulating the house thru the return ducts and the h-stat determines it needs humididty.
 
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Old 01-11-07, 02:47 PM
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Do you have water comeing out of the drain when the furnace is on??????. You do have to be back off that test line for it to run.
 
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Old 02-05-07, 07:26 AM
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Now that is is a little colder here and my furnace is running more I have been observing the operation of the humidifier some and it left me with a few questions.

The humidifier is connected to a Carrier furnace via the HUM terminals. This terminal is live whenever the burners are on. Knowing this, I observed the sequence of events like this:
1 - Burners come on (HUM terminal live)
2 - Humidifier comes on (yes water seen exiting the unit)
3 - The furnace blower comes on

What I am questioning is there is about 30 seconds between steps 2 and 3. Now it would seem to me that the blower would need to be on to get the moisture throughout the house and it does 30 seconds after the humidifier is on and the blower kicks in.

I think my concern is the moisture is getting into the duct work for a little bit of time before the blower comes on could cause problems. I don't see any immediate problems of moisture build up when I removed the humidifier and looked into the duct work and A coil. It felt bone dry. I guess eventually the warm air blowing in the duct work may dry any thing up if there is any moisture and perhaps the fan on the humididfier itself may push the moisture along.

Are my concerns valid?

I am also thinking about hooking up the humididifer up to the EAC (Electronic Air Cleaner) terminal instead. I think??? that these terminals are live when the blower fan is on. Does anyone know for sure? Also, I see an EAC1 and EAC2 terminal, is one of these hot and one neutral? I know for a fact that I will need to step this voltage down.

I'm not exactly sure what I should do, I think I may just keep it the way it is now to the HUM terminals providing this is not causing a problem as I described.

Thanks!

BTW: I have noticed some condenation on the windows (at times) about 1 inch from the bottom of some window, so I feel the humidifier is working properly.
 
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Old 02-05-07, 06:35 PM
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So do these outdoor temp sensors work as good as they say?

Tonight I noticed the humidity in my house was around 20%. I went to the humidifier and turned the knob on the humidistat, but it was on the highest setting so it would not turn on the humidifier (doing this while the furnace was on). I then took off the outdoor temp sensor and put on the manual resistor, waited for the furnace to kick on turned the dial on the humidistat and it went on at 7, rotated it counter clockwise and if clicked off at about 5 1/4. Wow...

I then proceeded to measure the resistance with an ohm meter of the ODT and it was 58.8 K ohms and it was 12 degrees outside. This seemed reasonable according to the chart in the installation manual, so hmmm.

Just wondering if others might have similar experiences.

I am keeping it in manual mode for awhile.

Thanks
 
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Old 02-06-07, 12:29 AM
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Steve123
If you have the manual resistor on there. and the blower is running the humidifier should come on with the dial just off test anf thehome just 22%RH

You do have that small switch in the control set to C for the 700
 
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Old 02-06-07, 07:09 AM
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Are you referring to the switch that sets the humidifier type from bypass to power? If not, can you tell me what switch you are talking about?

Thanks
 
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Old 02-07-07, 07:18 AM
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I think you are referring to the small dial that has settings A, B & C that controls the change panel indicator light. If so, not sure what that has to do with the operation of the humidifier itself.
 
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Old 02-08-07, 02:07 PM
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Amazing that I found this thread.

I was just checking out my Aprilaire 700 today. My electronic house thermometer (oregon scientific) claims my indoor humidity is 20%. Ouch!

My unit runs (I keep it in Manual mode, maximum humidity, NO outside temp sensor). But my humidity never gets above 30% in the winter. It just seems worse this year however.

Let me explain my circumstances however. I live in Atlanta, GA. It can very often by very sunny and 50s to 60s in the winter and VERY dry. So the sun warms up the house...and thus the furnace doesnt run. AND, I have two units...one in the attic for the upstairs and one in the basement for the main level. The main level is the only one with the humidifer, the attic unit has no water source and isnt recommended due to the lack of climate control up there. (it was 18F here two weeks ago...I bet the attic got below freezing as the furnace is above the insulation).

Therefore, the furnace just doesnt run that much. Would everyone agree here? My humidifer pad seems to be OK and everyone runs.

The low humidity is just killing us...not to mention the woodwork cracking etc. Very annoying.

I would hate to setup a bunch of portable units.

Other solutions?

thx
Jim
 
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Old 02-08-07, 03:59 PM
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I am beginning to think that my digital hydrometers that measure humidity are not accurate. I often see condensation on the windows, especially in the morning. The condensation covers only about 1" of the bottom of the windows,. According to charts that I have seen, this equates to about 40% humidity. I think I'll use the windows as my guide!

here is the article:
http://www.achrnews.com/CDA/Articles/Service_and_Maintenance/147bdb11d7d5a010VgnVCM100000f932a8c0____
 
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Old 02-08-07, 11:43 PM
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Steve123 Its a lot in how cold it is out side for what you want the R/H to be in the home At +40 ---45%
+30--40% +20---- 35%

Are the windows single or thermopane--double glass
 
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Old 02-09-07, 07:12 AM
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double pane.

The condensation isn't evident all the time. This morning, it is just a little moisture (not big droplets) on the bottom of the window (bottom, 1/2 inch). I hooked up the temp sensor again a few days ago, so it is in automatic mode. My hydrometer read 30% upstairs, 25% down stairs and it is about 20 degrees out this morning. This seems to me perhaps to be about right.
 
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Old 02-09-07, 08:31 AM
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My digital ALWAYS shows less than the 'manual' dial hydrometer I have. (I think hydrometer is the correct term). I never have window condensation. My digital gauge still said 23% this morning after having the furnace run over night.

How often do you change the humidifier pad? I checked mine...it has very very minimal calcium deposits on it...looks just like the new one (I have a spare).
 
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Old 02-09-07, 09:43 AM
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smithsonga
Do you get a small amount of water running out of the over flow on it. When the unit is running?????
 
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Old 02-09-07, 02:14 PM
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I'm also in the St. Louis area and have an Aprilaire whole house humidifier. This winter, in particular, I have noticed the humidity level in the house to be lower than past years even with the humidifier working. I also have a co-worker that said the same thing. It's just been really dry this winter. I also get some condensation on the windows in the morning when it's really cold and have noticed no static shock. I can also turn the control knob when the furnace is on and hear it click on or off at certain settings as well as see water running out the drain when it clicks on. I have had it between 5 and 6 this winter, but usually leave it between 4 and 5. When they installed the unit, the connected the outdoor sensor and left the manual override. I have not had any problems, so I have not bothered to use the manual override. I have also had two sick kids lately so we have had the cool mist humidifiers going in their bedrooms at night to help with the colds, so that has helped a bit too. Just thought I'd throw in my .02 since I'm in the same area of the country.
 
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Old 02-09-07, 02:38 PM
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Thanks Nuzy.

Just curious, in the past years what kind of humidity levels have you been able to get? How large is your house (SQ FT)? This is my first year with the humidifier.

I'm also thinking about hooking it up to the EAC terminals with operate whenever the fan is running, unlike now when it runs when the burners are on via the HUM terminals (on a Carrier). This way I can set the thermostat fan to on and run the humidifier whenever I want as opposed to having it run only when the furnace burners are on (i.e the heater is running).
 
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Old 02-09-07, 08:24 PM
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It's hard for me to say with much accuracy because all I have is a crappy holmes hygrometer, but based on that, during a typical winter I would say I am in the 45-55% range. This winter the needle seems to be more in the 35-45% range. In either case the needle is pretty much within what the hygrometer labels as the "comfort zone," although I believe 55% is at the high end.

Our house is an atrium ranch with 1800 sq ft on the upper level and another 1100 sq ft on the finished lower level. I have the model 600, not the 700.

I have not considered changing the wiring to run when the fan is on since the house still seems to be pretty comfortable. I run the fan all day to keep the temp even throughout the house, so I imagine that would add a measurable amount to my water bill if I had it hooked up that way.
 
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Old 02-10-07, 10:51 AM
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Originally Posted by Ed Imeduc View Post
smithsonga
Do you get a small amount of water running out of the over flow on it. When the unit is running?????
YES.

I put my digital temperature/hydrometer next to my furnace duct. that wsa funny....it ended up at 106F and 15% RH coming out of the vent. How can THAT raise the humidity in my house?!?!

If the powered humdifier is set to run with just the fan on, how well does it evaporate the water? I have mine setup with the cold water line, not hot. Would that make a huge difference?

many neighbors here have the same unit and feel as if it was never installed...just doesnt seem to function well.
 
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Old 02-10-07, 11:57 AM
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Has anyone tried one of those mister type humidifier's that go in the ductwork?

Thermomist is one brand. heat activated and sprays a fine mist that evaporates immediately in the hot air. Can put 12 gals/day in the air (probably if the furnace runs all day).
 
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Old 02-10-07, 11:21 PM
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smithsonga


Dont do it No way. Will rust out duct, put lime and calcium dust in the home and jam the filter fast.
 
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Old 02-12-07, 07:03 AM
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Originally Posted by Ed Imeduc View Post
smithsonga


Dont do it No way. Will rust out duct, put lime and calcium dust in the home and jam the filter fast.
Well, the whole house humidifer option doesnt seem to work in ATL. maybe it just isnt cold enough for the furnance to run enough...I was able to increase my son's room only with a room humidifer from 20% to 27%. I hate refilling those things and they arent exactly germ free either.

Just another of life's many annoyances that wont go away.
 
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Old 02-12-07, 07:25 AM
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smithsonga On that spray hum Like I said dont do it. if you check we have over 5 post here. That say that that kind has got their duct work and furnace that is rusting out. Now you say you have two furnace's one up and one down. With a two story home you should have .Try and push the temp up a little more on the down stairs one and push the tstat down on the upstairs one some. See if that will kick up the R/H in the home more. that 700 should put out all the R/H you need there. Is it on the heat plenum or cold air drop?
 
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Old 02-13-07, 06:07 AM
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Thanks Ed. I understand the rusting out. I would add one point, my air ducts are all insulated flexible ducting...the only metal is the spiral within that duct and the plenum is metal.

Given that, my unit is on the hot air side with the humidstat on the return plenum.

I am curious what others get on their temperature/hydrometer at the heat duct in their home. I was low 100s with about 15% RH. Curious if that is the norm for an operating humidifer.
 
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Old 02-13-07, 04:47 PM
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With fiberglass duct you sure dont want the spray kind in there. Also it will put a white duct all over the home. I have a 700 in the home here temp in side is 69F R/H is 44% out side is 23F. I have good windows.
 
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Old 02-15-07, 06:52 PM
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Low Outside Temperature / Aprilaire 700

So, I too have an Aprilaire 700 (connected to the hot-water line) and have observed that... as the outside temperature falls into the 20s and below, it's practically impossible to raise the inside humidity past a certain point. Last year I used the stock humidistat installed by the HVAC guy and had very poor results. So a few months ago, I built my own. It has worked out -much- better. Check out my graphs:

http://www.wozzle.com/zac/temps/

A few things to note:

1) The humidity setpoint is 35%. The temperature setpoint is 73 or 74.
2) I have no idea what those spikes are on the humidity graph...
3) Note that the humidity generally falls during the coldest periods, in spite of the fact that the heat pump has failed over to emergency heat (higher output temp) and the utilization factor is /still/ around 80%.
4) I don't ever notice condensation on the windows...

I've recently considered dynamically lowering the humidity setpoint as the temperature falls, just to avoid dumping so much hot water down the drain ($$$).

Zac
 
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Old 02-15-07, 10:56 PM
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I've recently considered dynamically lowering the humidity setpoint as the temperature falls, just to avoid dumping so much hot water down the drain ($$$).

Zac

There should be a very small amount of water going out the bottom drain on that 700. With the unit and furnace on
Close down the water valve to the unit some till there is just a small amount of water running out the drain.
Im like you I dont know why the humidity went up with the outdoor temp. I seem to stay about 40 % here all the time . Even with the temp going up and down. To night we should hit about 6F .I know its to much but I feel better. This is with a 700 on a heatpump
 
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Old 02-16-07, 05:23 AM
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Originally Posted by Ed Imeduc View Post
There should be a very small amount of water going out the bottom drain on that 700. With the unit and furnace on
Close down the water valve to the unit some till there is just a small amount of water running out the drain.
Yeah, I've had the same thought. Unfortunately, the !?!@#! saddle valve leaks when I turn it down. Any idea how to fix that?

Zac
 
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Old 02-16-07, 05:54 AM
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Zac,

Get rid of that saddle valve and replace it with this..

(Copy and paste)
http://img170.imageshack.us/img170/3116/pict0449fa3.jpg
 
 

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