humidifier install questions

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pybyr

Minister of Fire
Jun 3, 2008
2,300
Adamant, VT 05640
This isn't boiler-specific, but I find that those most familiar with whole house systems gravitate to the Boiler Room.

My Econoburn 150 and associated system (water to air HX in preexisting ductwork, with air moved by the blower in the preexisting ThermoPride oil warm air furnace) are heating my (previously hard to heat) 19th century VT farmhouse superbly.

I can actually run temperatures warmer than I could have ever thought of before; the only downside is that my air is-- correspondingly-- dryer than before (and since it's no longer worth trying to add heat with my wood cookstove, I no longer have a steaming pot on the cookstove to add moisture to the air).

A friend has given me a nice quality/condition bypass-drum humidifier.

I know that these are typically installed in a manner where they go between the return duct and the warm air duct; I don't want to do that in my install, as I figure that's inviting moisture to condense on the steel innards of my oil furnace, which is on the cold side of my wood system's HX.

I am toying with the following ideas--

(1) bypass HX in the warm air duct with a muffin fan to pull air through the bypass humidifier (although I hesitate to put a muffin fan in the heated airflow, as that's probably above it's temp ratings; or

(2) a "take off" feed from the warm air duct that has a "scoop" inside the duct to steer some airflow into the humidifier.

I'm leaning towards (2)--- anyone have any experience or other feedback on how well this might work, or effective and simple ways to arrange it?

Finally, any nominations for effective but affordable "smart humidistats" that take outdoor air temps into account? Or other affordable but reliable humidistats?

Thanks, as always, for the opportunity to solicit input from the Boiler Room's collective minds.
 
Moist air in the house is nice in the winter but it can also cause some real problems. Mold. If you are getting condensation on your windows when we have cold nights 20's or teens you may possibly have all the moisture you want in the house all ready. If you are getting that interior air escaping into wall cavities or attic spaces that same moisture will frost, not dry out quickly and mold.
I had an unrelated roof issue that caused some water damage but in doing some research on mold, roofs, venting I ended up getting a couple of humidistats and promptly shutting off my house humidifier. It's been off for 5 years now. We heat with forced air and our humidity stays at 50 to 60%. I was shocked that it was that high.
There are a bunch of variables that factor into the equation but I would look at existing humidity first.
To help can you lower the water temp going to the coil any or slow down the fan speed to make the system a little more passive ?
Rob
 
House is dry as a bone this time of year- condensation on windows is an extreme rarity. Walls are insulated with dense packed cellulose, which is pretty good at dealing with moisture within any reasonable parameters. Anywhere I've had wall cavities or ceilings open during rennovations, I've used cross-linked poly vapor barrier.

I know that I'll need to keep a close eye on things, but I still need the humidity-- nosebleeds, crusty sinuses, etc., are no fun.
 
pybyr said:
House is dry as a bone this time of year- condensation on windows is an extreme rarity. Walls are insulated with dense packed cellulose, which is pretty good at dealing with moisture within any reasonable parameters. Anywhere I've had wall cavities or ceilings open during rennovations, I've used cross-linked poly vapor barrier.

I know that I'll need to keep a close eye on things, but I still need the humidity-- nosebleeds, crusty sinuses, etc., are no fun.

Currently it's 18 degrees out and the humidity is 32% on my humidifier. I've seen it just above 20% when it was -10 out. I thought this was too low until I Googled a little. 50-60% at this time of year sounds pretty high.
 
I had a whole house one hooked up and used it for a year. I liked the fact that I didn't have to do anything (add water) with it but I have hard water and it was a pain to keep it clean. Worked great when new, but after a few weeks it would cake up and I spent allot of time trying to keep the damn thing working. I ended up getting rid of it and now I'm using a large table top unit. I have to fill up a jug everyday but its allot easier in the long run.
 
I found an install picture of a drum system that looks like it bypasses all HVAC equipment. I also did a quick drawing of how I pull out side air into house without extra fans, (venturi effect I think). I bring in outside air, filter it, heat / cool it and goes out to the home thru the ducts. You do have to watch out for freezing your coils in winter etc. But this works well for me. ( my 50% humidity reflects the warm rainy days we've been having to some amount )
If you were to install like the picture from http://www.cornerhardware.com/howto/ht081.html and on the line where the humidified air returns to your duct you had a little scoop I think you might get all the suction, through venturi, you need. My scoop is pulling air through 25' of insulated plastic flexduct and I keep the damper bout 1/2 closed because it sucks so much. Could you mount the unit on one end, before HVAC and duct around with plastic duct?
iaqsource.com has a lot of filters, and controls.
Rob
 

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