I presume double stage means that at one temperature one heater is turned on and at a lower temperature a second heater is turned (boost).

You can reverse the 2-stage concept for cooling too. I use a two stage thermostat to open the intake louver 4 degrees F before the exhaust fan turns on. The advantage over two separate thermostats is that the units are always coordinated. You may get by with a little less wire too depending on how you position everything.

On the other hand, sometimes it is better to run the feedback loop through the thing being measured - use two independent sensors, one for each subsystem.

oy, too technical for me!

Can someone detail this out in easy to understand terms so I can give my hubby the details, like - how many thermostats to get, where to place them, what to hook each one up to, etc?

thank you!

d

plant.babies wrote: "Can someone detail this out in easy to understand terms so I can give my hubby the details, like - how many thermostats to get, where to place them, what to hook each one up to, etc?"

Since I don't post here that much anymore, I'll be the one to say this (potentially saving others your upset response)..Its really unreasonable (on a number of levels) to ask that folks provide you with the info you requested in the quote above. Bear with me and I'll try to explain why I think so...

We ALL have needed help (yep me too) and folks are usually ready to provide that help but....you do have to bring a certain about of your own resources to the issue before you ask for that kind of detailed help.

It's kind of like a question I saw in an online "home electrical forum". Someone asked what seemed to be a simple question about wiring up a 110v vs 220 v oulet. The best reply that came in was "If you have to ask that question, you need to hire an electrician to do the work"....meaning that the inquiry indicated that the person did not have enough basic information to use the answer to the question in a safe and reliable way.

Aside from the fact that thermostats (obviously) use electrical connections in a wet (gh) environment (a potentially dangerous combination), you really need understand a bunch of the basics about electrical wiring, how you envision your gh to work, what are your planned table heights, are you planning to mist the gh, heat the gh, and on and on....all of these, in one way or another, contribute to the issue and hence a better forumlated the question.

You are going to have to research, read, compare and ask smaller step by step questions before (In my opinion at least)you really know "what" your question is.

All of this techno stuff (fans, heaters, humidity control etc) needs some level of installer/operator understanding before you go out and buy and connect it all up. I'll bet you money that when (not IF) your cooling thermo goes south some hot day, you won't have time to ask the forum how to fix it and wait for the replies. You must have taken the time and expended the energy to know most of the basics yourself so that your questions to the forum are to clarify or ask for verification on what you've already learned yourself. That way you'll be self confident and prpared to handle the situation yourself.

There is an amazing amount of info out there..between books on ghs, old forum postings, info sheets from parts and equipment suppliers, etc....take a look, you'll find some great stuff.

Believe me please, I AM tryng to help, not offend ...though its probably not the answer you wished for.

Steve

no offense taken,

I didn't really want "wiring diagrams" -- I simply wanted to know:

'how many thermostats does all this equipment really take!? and where do they go'?

From reading (defintely as much as I was able to find), it seems like you need a thermostat for fans, thermostat for the exhaust system, thermostat/humidistat for misting system, thermostat for heater, another for cooler, AND so on......

I think -- to be very specific -- what I am really asking is: is it possible to get several things to work automatically together, with less thermostats than having a separate one for each system?

:)

You could probably get away with a thermostat for heating and a thermostat for cooling, or if you rarely do both (which is something you should really aim for) just one with a summer/winter switch.

I too looked at the "master" thermostat in my house that controls the furnace and AC and thought the same would work in my GH, until both Eric at ACF and my own H/AC pro. disabused me of that notion.

Unless you are getting into some truly complex and expensive systems, the heating and ventillation in a GH are best left on separate thermostats, and the single stage, wet location ones sold cheap (less than $35.00) from ACF, will do the job nicely.

KISS

Plant babies
You you can have multiple system working together. They are called environmental controllers and can be quite expensive.

Here is a link that might be useful: Controllers

thanks everyone - I will make the systems separate, but tie the exhaust/heater together so they aren't on at the same time ... I think.

I am looking for LOCAL help - someone who hads a gh and 'been there, done that'

I want people to tell me what mistakes they initially made!

:)
d

There are lots of possible configurations which others can advise better than I. However please note the following advice I have given before.

* Posted by domeman on
Sun, May 28, 06 at 16:51

When dealing with mains voltages - if your expertise is such that you need to ask how to do it - then it is best to get someone else to do it for you. Especially in a situation where there is water involved..........

"Unless you are getting into some truly complex and expensive systems, the heating and ventillation in a GH are best left on separate thermostats."

BW, we don't seem to agree on anything! I use a Bartlett controller and I love it. Everything is coordinated together with a single unit, so the exhaust fan doesn't come on before the vents open. Heat and cooling are controlled together. I run my mist system signal through a relay controlled by one of the cooling signals from the controller...works like a charm.

stressbaby, can you come to my house and make one of those systems for me? LOL... Can you tell me where you got your controller? I am hoping a controller situation would be near the cost of having four separate thermostat setups.

I really should not worry so much -- my hubby can and will do up the electrical as it should be -- he did our whole house.

This is my "baby", so I feel I should learn all I can by myself first. Once the gh starts going up, I'll have to step out of the way, so to speak. Except for those valuable times when I just have to say "hey, that won't fit!". I am usually right.

:)

Incidently, I used to use a controller designed for controlling split cycle airconditioners/heat pumps. It had a digital read out that I could put inside the house on a wire, three different fans speeds and separate cool and heat relays (and a de-ice relay, which wasn't very useful to me) It cost me around $50au and I used it to control misters and an old evaporative cooler.

Plant,
Earlier in the thread I gave you a link to many types of controllers. Have you researched those yet? Also, If you would contact a reputable dealer when buying your g/h all this work would be done for you by their sales department.
If you tell them you have a budget of 16k for the project you bet they will help you and listen.

Nathan,
Was your controller built for the g/h environment? If not I would have thought twice before installing it.

mylu: why? The only thing in the greenhouse was a thermistor, embedded in a plastic sheath. There aren't many electronic devices more robust than a thermistor. The controller itself lived in a ventilated wooden box on our verandah.

What is your fear of using non-officially-sanctioned equipment in a greenhouse? (do you perhaps own a greenhouse supplies shop ;)

That Bartlett is way beyond my simple needs. My gh is only going to be 12x16

I don't think we want to take on wiring up something like that either. ... many thanks for the info anyway! :)

d