quote:

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Originally posted by vt
n6ber:

Can't do. I'm using triacs and optoisolators; this setup is sensitive to the nature of the load. However, solid state switches are way more reliable than relays.

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Well, I, on the other hand, don't trust the relays

Here's what I'm using:

http://rocky.digikey.com/scripts/ProductInfo.dll?Site=US&V=33&M=Q4015L5

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--vt

I can understand not trusting relays but remember the furnace and A/C, even the new ones, have several and that's what you are controling. Also reed relays are sealed so no dust or any other contaminate can get in to keep them from closing. They are rated in the millions of operations.

I guess we will have to agree to disagree.

Yup

There are other considerations I'd rather not get into here.

All in all, this is R&D Drop me a mail, we'll talk.
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--vt

There may need to be another area on the forum.

DIY ENGINEERS.

They can go there and rap about static pressures and deep things. There could even be a memorial wall to the ones that blew themselves up at home.
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Today we did what we had to do. They counted on America to be passive. They counted wrong -- Ronald Reagan

VT,

Seeing your motorized damper setup was interesting. Just curious if there are code requirements for electrical components sitting inside ducts? I know your not allowed to run wire (even low voltage) in a duct. If I'm not mistaken, my trol-a-temp dampers have the motor on the outside of the duct, and only have the blades inside.

Hey, do you see a DIY Engineer around here? I don't.

quote:

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Originally posted by seismo
VT,

Seeing your motorized damper setup was interesting. Just curious if there are code requirements for electrical components sitting inside ducts? I know your not allowed to run wire (even low voltage) in a duct. If I'm not mistaken, my trol-a-temp dampers have the motor on the outside of the duct, and only have the blades inside.

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You can run wires in a duct, but they have to be "duct rated." I learned that on this web site a couple months ago, while researching a thread titled "duct rating."

"Duct rated" wire is capable of handling much higher temps than normal HVAC wiring requirements. And, "Yes" most damper systems (like Trol-A-Temp) work via motors outside the duct. The alternative to this is to use air powered dampers.
__________________
There are no stupid questions. . .just a lot of inquisitive idiots.

quote:

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Originally posted by BamaCracker


You can run wires in a duct, but they have to be "duct rated." I learned that on this web site a couple months ago, while researching a thread titled "duct rating."

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quote:

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Originally posted by n6ber

quote:

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Originally posted by BamaCracker


You can run wires in a duct, but they have to be "duct rated." I learned that on this web site a couple months ago, while researching a thread titled "duct rating."

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I think that would just be standard "Plenum" rated cable, we use that all the time, or did they add a new cable rating I have not seen yet?

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Oh, yeah, "plenum rated." Well, duct rated, plenum rated, what's the diff?

Actually, you are right, it was plenum rated.
__________________
There are no stupid questions. . .just a lot of inquisitive idiots.

I like Plenum rated cable as it pulls easier than normal cable but I have never liked the price. That stuff costs almost double what PVC costs. I always have to watch some of the cable installers. They don't always understand what a Plenum ceiling is or how to figure if they have one. I would not be suprised if you have found PVC in Plenum ceilings.

James 3528:

I see

Well, laugh all you want, but let me tell you a story: three years ago, a new guy showed up at my office. He was 43, professional bass guitar player, just finished some entry level courses because he felt that his profession didn't have any future, and got a job. Well, I, a professional with 15 years behind my back by then, smirked (duh). Guess what, 6 months later I was following his advice when I was building my home box. Works 'till now with no problems, turned out to be a really wise decision, scalability-wise.

I just hope I can get as good at HVAC as this guy got at computers. Well, that's why I am here. With humility, I accept the advice of the ones that know what they're talking about.
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--vt

seismo, BamaCracker, n6ber:

I didn't really stuff the cable into the ducts (yet), it's just stapled to the wall - this is experimental setup, all in all. But, I did use a plenum CAT5 cable - got a 1000ft roll real cheap, by accident.

I don't like an idea of anything being in the duct, no matter whether it burns clean or not - it might rattle, whistle, and the metal duct is a conductor (watch for shorts), plus I don't like the idea of fastening anything to the surface which properties I don't know (whether there's another 110V cable right behind it or not, I have no way of knowing).

Besides, from the cost-efficiency point of view the wireless solution can be quite feasible - the controller and the remotes cost about $250, which makes sense compared to the cost of conventional wiring - local guys take $100 for a drop. Now, 10 rooms in the house...
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--vt

BamaCraker,

re: "while researching a thread titled "duct rating."

I've search the site for "duct rating" and just plain "duct" and couldn't locate the discussion you mentioned regarding the placement of wires inside heating ducts. I am curious about this point however and a bit confused as previous discussions I've seen on the comp.home.automation newsgroup suggest this would be a code violation.