Computer controlled zoning for less?

[giddonah]

I haven't read through all of this site, but at first glance, this looks pretty cool. I was wondering if I could get some of you guys to check it out and tell me what you think:

http://diy-zoning.sourceforge.net/index.html

[bkrahmer]

It's funny you bring that to attention. I was just telling my wife this weekend how I would like to convert the house to an electronic system (and the damn house isn't even done yet!) much like what I see in the FAQ. I'm thinking of using a Stamp controller with some temperature sensors placed in the current thermostat locations (5). I wish I would have just used CAT5 for my thermostat wire instead of 18/2. I have a radiant system, and I'm thinking that in low demand times, I could cycle the pumps long enough to flush new hot water into the lines (about 3 minutes), and then stop for a calculated time. It should be able to keep a zone constant within +-0.5F. It might cost $200 or so for the stamp setup, and it wouldn't depend on (any one of) my PCs being on. Since everything would be controlled by easily changed code, I would probably end up experimenting with monitoring loop return temps as well. Fun stuff...

[rabadger]

I have honeywells electronic residential zoning in my home. 3 dampers, 3 setback stats, furnace interface, and zone controller. Works great. All zones are setback stats, each stat takes 18/3, they can be programed independantly, and I installed the optional outdoor air sensor. I walk up to any stat press the button and know the outdoor temp.
the stats have a 30 day timer and I am reminded to check the filter.

If you are a builder Honeywell has some great programs out there

In hot water applications you can really get crazy with the electronics. But the thing is how do you figure the break even point?

[rabadger]

I installed 3 zones for less than 500. 3 T8600 stats
3 dampers, zone interface, equipment interface, transformer. Did not need bypass damper. Works fine. Best thing I ever did.

Your biggest problem is figuring if the duct work is correct to handle it. You can realy destroy some equipment if you are not careful. It doesn't take long to loose the valves in the compressor if you start freezing the A coil and get liquid back to the condensing unit.

[giddonah]

so Rich, are you saying that the guy exagerated the price of conventional zoning methods?

[rabadger]

I admit I got a great deal from the factory. Not everyone could do what I did.

It all depends on your needs and how far you want to go with it. In my case I did not get the optional dump or bypass damper, PC interface, or remote calling to let me adjust the home temp from a lap top in a hotel room. I did not have to put in the freeze protection control for the condensing unit.

There are manufacturers rebate programs, factory offers to builders etc. My materials came directly from the factory UPS. If you were to hire a contractor to install the same system I have, and supply the parts, it would cost approx. 1500.00 in my area. If you know the offers out there you are better off when shopping. Zoning is best when everthing is sized correctly. Unfortunitly that's not always the case. It can make a bad system worse it you are not careful.

[giddonah]

so then what do you think of that site Rich?

[rabadger]

A lot of it justs adresses the basics of zoning. Auto zoning for residences has been around. There were a lot of trol-a-temp systems out there when I entered the industry in 1977. Honeywell is the old trol-a-temp line.

Air flow is the key. Trol-a-Temp always stated that each zone has to be able to handle a certain percentage of air flow.

I cheated and did it this way. (don't tell anyone) I undersized the dampers so each zone had some bypass. I did not have to rip all the duct work out of the house. Air takes the path of less resistance. I run my fan on constant. When zone 1 calls for heat zone 2 and 3 dampers shut. When zone 1 is satisfied zone 2 and 3 dampers drive open. They are power to close and spring open. When I do zoning I always open the book and do the prep work first.

It gets more complicated when you introduce variable speed drive equipment and two stage air conditioning. I don't think I would try any short cuts as of yet.

I just surfed the site breafly. It looks like they are mostly stating everything the manufactures of zoning products have known for some time now.