Bypass humidifier question (Aprilaire 600 specifically)

Hello,

I have two questions. I am looking specifically at the Aprilaire 600.

(1) Would I be adding inefficiences to the system if my bypass duct is long and jogged serval times (approximately 7 feet of duct, as I have a horizontal unit and I have to get from the supply to the return)?

(1a) If there are inefficiences in this would it be recommended to use the 700 instead?

(2) Can the same unit be configured right-hand or left-hand? I don't know if I am going to put on supply or return yet (question of room), but I do know that I have to go on the front of the unit.

Thanks for the help...

 

1- As long your got a good flow, but if it's jogged a few times, I'd question on it.

My big question is, where is the furnace at? Attic, or Crawl space?



2- Most by pass unit can change the pipe hook up to left or right side.

 

Thanks Jay,

The unit is in a tall (easily stand-up) crawl space. It is a horizontal unit with single speed fan that is a heat pump with backup propane; the propane runs most of the winter.

I have a picture here:

http://i243.photobucket.com/albums/ff229/hokiedale/Dsc03523_1.jpg

Can I use a flexible duct for this application. I have seen posts where others have used this type?

Any advice you can give would be appreciated.

Thanks again,

Dale

 

You could put the humidifier on the back side on the return side, then go right to the supply above the A-Coil.

A couple of questions.

- With the exhaust being wrapped up, I am guessing this space get below freezing?

- Why the bucket under the coil, is it leaking?

- At what time is the furnace running all the time? What is being used for t-stat/control for this set up?

 

That’s an idea that I have not thought of. Is it acceptable to do this? I guess you would be okay as long as you only cut through the furnace box (as a do it yourselfer, I didn’t want to cut something open that I could not repair).

In theory, it could get below freezing. My pipes aren’t wrapped and I haven’t noticed any problems in the past, and I am down there quite often (the unit is in the center of the crawlspace). The vents stay closed and the crawlspace is 4’ - 10’ feet tall (mostly 6' +). I am a little concerned about the water coming out of the humidifier, but I thought I would give it a try. I have hot water access close by, but it is at least 20’ from the hot water heater, so I think that it would be pointless to hook to it. We don't get many days below freezing in NC.

I was wondering if anyone would notice my bucket. During the latter part of the summer, I get quite a bit of humidity down in the crawlspace. I am tying different things to alleviate this but I still get a little condensation on the supply duct and the air handler; there is not a lot of water, but I do like to keep the water off of the VB. I am down there quite a bit with it being such a large crawlspace (I should have built a basement), so I like to keep it neat and clean.

I am embarrassed to say that I don’t fully know when the fossil fuel takes over vs. the heat pump (if I understand your question). I think that the LP (backup) kicks in when the heat pump cannot keep up w/in 2 or 3 degrees (does this sound right?) I do know that certain units can be configured so that the LP is the primary below a certain temperature (and that this saves the defrost cycle for the heat pump), but I don’t think that this is my setup. Is there a way to tell other than calling the original installer (there is no external thermometer)? If it is not set up as such, would this be a better setup from a humidifier standpoint. I understand that humidifiers either do not work w/ heat pump or do not work well.

 

With the set up you have there Id for sure put a Aprilaire 700 in the plenum . For get the bypass kind. You dont need that long a by pass.You can run the over flow line from it right into the drain line you have going from the AC drain line there . There is not much water that comes off the 700. This is the unit we use most of the time on the heatpumps or furnace . Might also check on that Lp gas there. Hear cost is going up on it. Go http:// warmair.net and compare fuel cost might pay to run the H/P more

 

I appreciate the continued replies. I still am undecided. I like the 600 because of the less parts for something to go wrong with. I also like it because it will use less power to operate than the 700.

But ... which is better with the heat pump? And which is better knowing that I will not be able to supply hot water?

Thanks again as I am struggling with the direction that I want to go.

 

Either unit is fine.. I am with you about less parts on a by pass. DO NOT cut the furnace or coil box! Only mount this on the ductwork itself.

If you do get a humidifier, I'd still tap into the hot water to at least try to keep the water line from freezing if it does freeze down there. Also the hot water will help with adding more humidity to the air when the heat pump mode is running.

I was going to ask why not make it into a basement since you already got that head room?

Please post the make and model # of your t-stat. I can see what you got for control of the heat pump vs gas.

 

I originally had a white-rogers, but it wasn't programmable. I replaced this with a Hunter model 44760.

Thanks for added input.

I guess I misinterpreted (out of my ignorance) an earlier post when you mentioned going into the supply above the coil box. Did you mean the insulated flexible duct coming out the right hand side of the top of the plenum? Can I tie into this without doing too much damage?

The basement thing, too expensive for where I am in life right now ...

Again, very grateful for input.

 

No, just mount it on the metal ductwork.

Is there a control between the t-stat and furnace it self? I looked at the t-stat papers, and nothing is shown there that it controls the heatpump lock out when the outdoor temps falls at X˚.. ect. So, there should be a control between the two to do this job.

 

I called my HVAC installer. He said that the system was set up with a thermistor on the heat pump that would shut down the heat pump and kick the LP in at around 30 - 35 degrees. I was skeptical because this was not what I was told originally. So, I looked for the thermistor (which I believe should be just a bulb), and it is a noshow. I opened up my furnace and the PCB confirmed that it is not set up this way, as the schemic shows a tab should be broken out (to disconnet a circuit) should an outside themostat be included. That tab was intact. It is too late to call today, but I am going to call back tomorrow to reask the question.

On the mounting front, please take a look at the picture (a picture is worth a thousand words);

http://i243.photobucket.com/albums/ff229/hokiedale/Dsc03523_2.jpg

is this the correct setup if I go with the 600? Another question that I have with this setup is that the humidistat will be on the return as well, but because of length, do I have enough room to get it sufficiently far away? The plenum is approx 34" w; I can't put my hands on it now, but I believe the model 600 is 15" w. I do not know how big the humidistat is but lets call it 6" w. That means the humidistat would be, at absolute best, 14" from the humidifier. Is this enough distance?

For the 700, I would mount in where the bypass hook up to the supply is in the picture represented by the red circle??? The humidistat would still go on the return.

I apologize for taking up all of your time.

 

Also Jay,

I have been doing further research on the 700 and have read the comments that "The Aprilaire 700 should not be installed on horizontal flow ducting". Isn't that what I have here, and wouldn't that take this option off of the table?

 

Keep me posted about the control on the heat pump.

I'd drop the heat pump cut of further... make it 20˚, or more!

Put the bypass duct on the back side of the return.. No reason for it to "jump over" to the front, unless I am not seeing a reason why you can put it on the supply side.

The humidistat, I'd put it on the return far back end. The unit itself, close to the furnace return.

 

I did get confirmation that the heat pump shut off into the backup furnace is not controlled by an outside thermostat. After speaking with the HVAC contractor, I am still not sure how this happens; he confirmed that if the heat pump cannot keep up within 2 degrees that the switch to backup happens on the board inside the unit. This doesn't sound very effiecient to me; to me this says that the heat pump must come on and waste some energy before the backup kicks in (??). I think I will add an outside thermostat to the board (board number is Goodman AFE18-60A). The wires are already there; all I need to do is by and add thermostat. Are you familiar with this board?

Is there any site that I can go to to understand the cost shift between the LP and the heat pump. For example from your statement, I am assuming that it is around 20C (based on LP prices today).

Also, any comment on the fact that Aprilaire says not to put Model 700 on horizonal duct (is this the same as horizontal furnace? ... maybe I am getting confused).

The reason that I cannot add the bypass to the back side of the supply is because, you can see this in the picture that I sent) there are flexible ducts taking up the entire top side of the supply plenum as well as the entire backside. On the return side, I only have two return ducts ... both on top.

We are getting there, slowly but surely.

 

What brand/model of heat pump you have outside?

I'd go with the Honeywell VisionPro IAQ t-stat.

http://yourhome.honeywell.com/Consumer/Cultures/en-US/Products/Thermostats/Programmable/Professionally-Installed/VisionPRO+IAQ/Default.htm

The IAQ is a MUCH nicer t-stat than the Hunter you have now... I've heard mix results on the Hunter from other people.

 

Trane XR11 2TWR1036A1006AB.

I am not sure that I want to go through the trouble of adding a new thermostat to the inside ... I was going to add one to my heat pump outside.

 

Putting in the new IAQ is going to be no diffifrent than the Dual Fuel board... Matter of fact the IAQ will be better.

Otherwise, if you don't want to mess around with the board, or the IAQ, the dealer should come back and install the right part.
http://www.trane.com/webcache/un/unitary%20accessories%20(acc)/service/18-hd27d1-1_09012001.pdf

My big question, are you sure you don't have this outside?? I can't see how else it will go into defrost.

 

Nope ... no thermostat on the outside... the board and optional thermostat info is here ...

Board:

http://www.alpinehomeair.com/related/Goodman%20AFE1860%20Install%20Instructions.pdf

Thermostat:

http://www.alpinehomeair.com/related/Goodman%20OT18-60%20Install%20Instructions.pdf

The board instructions say that the defrost is controlled by a thermostat hooked to the defrost board in the unit itself. I have taken some pictures of the unit. Is the device hooked to the copper line (with the purple wires) a thermostat. I have also taken a picture of the unit with the cover off so that the board can be seen. I do not know if one of these is the defrost board or not.

http://i243.photobucket.com/albums/ff229/hokiedale/Dsc03532_1.jpg

http://i243.photobucket.com/albums/ff229/hokiedale/Dsc03533.jpg

 

Ok. my bad. I though you had nothing that controled the system.. YOu got the board now.. but nothing "locking" out the heat pump when the temp gets at a temp of X degrees.

The purple wire, I am not really sure what that is.. I have the XR11 as well, but it's not a heat pump.. I am guessing it's for the defrost. I really can't tell where that wire is going to.... Didn't see it go to the defrost board. (Small board with the Red LED light)

 

Hi Jay.

I found the schematic for the heat pump inside on of the covers that I took off. There is a connector off of the board that goes to a thermistor under this new cover that I took off.

I think that I will pay close attention to the heat pump this winter to see how it reacts during the colder days, as I am understanding the more that I look into this humidifier.

Hi Ed

My only remaining question before I start is 700 vs. 600. I see that it is not recommended to put the 700 on a horizontal furnace. I've reviewed posts here regarding the subject of the 700 on a horizontal furnace, and earlier this year (01-23-07) there was a thread in which you concurred that the a 700 could not be put on a horizontal furnace, but you highly recommended it to me below. I am a little confused. Can you please confirm (maybe you didn't catch the fact that my furnace was horizontal). Again thanks for your help...

 

I looked up the file, and yeah, I see that Aprilaire don't allow it on your set up.. Not sure why?? maybe it's the way it's designed, and air flow may have an effect?

I took a peek at Honeywell's, and they allow it, and even shows a picture of it being mounted on the supply side.