Hey, I'm getting an education too. In some respects it's fun. I like "thinking out loud" because it hopefully opens up possibilities and closes others. Finding something simple is sometimes hard. This seemed to be a mini fun research project as well. I'm used to getting things initially ridiculed, but as I'm telling it helps to home in on a solution.

There is cheap. There is easily serviceable. There is comfort. There is manual. There is automatic. There are combinations. You don't want things to be too complex that after you sell the condo, you have to provide a 100 page manual just to operate the HVAC system <G>.

A few things are now apparent:
1. There are no standards
3. There are low voltage and high voltage solutions.
4. Contact ratings were not addressed yet.
5. Most solutions are designed for hospitality industry.
6. The fan running all the time for some solutions makes no sense to me at all.

The most sensible system would vary the fan speed depending on how far the setpoint is from measured value. This results in the quietest system and the most energy efficient.

This is why I was trying to make a conventional thermostat stage select a particular fan speed. This gets off on the wrong track because stage 3 (fossel fuel) is way different than a heat pump. If the manufacturers of the tstat made the characteristics of the stages independently selectable rather than a system type, life would be easier.

The most sensible system would not allow one to get a blast of the wrong temperature air and would make it more marketable to a new buyer of the condo.

Having the fan run all the time defeats your purpose and won't work. Most stats being hospitality oriented with occupancy sensors and door open sensors doesn't help the selection. Your fan coil is super simple, thus you may have found out about the way your HVAC system operated AFTER you bought the condo. The guys building the condo put in the cheapest toaster (HVAC system) that they could find and your paying for it in terms of reduced comfort (high noise levels, no reduced temp for sleeping) and higher electric bills.

My proposed design is elegant providing assuming a stat with the following characteristics are found:

1. Programmable FAN coil stat
2. Multiple fan speeds that change automatically
3. A fan that won't run unless there is a call for heat or cooling.
4. The contact ratings for the fan is adequate in the stat.
5. A change-over sensor isn't required for the proposed stat.

#3 is a MUST.

There is still versions of HVAC1000's suggestions:

Place fan speed control at fan coil where it should not be moved when fan is running. Switch must be properly rated.

Place a seasonal switch in the fan coil area. e.g. Only allows heat or cool.

Variations of adding a contactor and low voltage AC supply to turn the fan on. The thermostat just uses simple on/off control.

And now we are almost right back where we started from adding complexity to make something else work or an elegant solution providing a better tstat choice can be found.

I may try to sketch a simple control ckt. The current tstat choice doesn't change the speeds automatically and it seems that the fan doesn't run all the time.

What are the markings on the blower motor label?

Marketing at its best?

Untitled Document

At 1/20 HP means it's about 40 W or about 1 KWH per day if running all the time. At $0.15/Kwh that means about 15 cents per day if the fan ran continuously, so energy savings isn't going to be the motivation. Contact ratings are nearly irrelevant.

It would have to be comfort and repeatability of setting the temperature.

Here is a quick and dirty sketch of a proposed interface.

Note how simple it really is.

Quote:

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Originally Posted by KeepItSimpleStupid

At 1/20 HP means it's about 40 W or about 1 KWH per day if running all the time. At $0.15/Kwh that means about 15 cents per day if the fan ran continuously, so energy savings isn't going to be the motivation. Contact ratings are nearly irrelevant.

It would have to be comfort and repeatability of setting the temperature.

---

Place fan speed control at fan coil where it should not be moved when fan is running. Switch must be properly rated.

The switch I used can be moved while the equipment is in operation. All it does is break the hot leg from contact and activate the other contact for the speed change. Switch rated at 10 amps. I use Baldor (yep the real expensive ones) for all my personal blowers on all my equipment. Last time I checked a 1/2 hp mptor was around 273.00 retail and 196.00 cost. In 50 years of using Baldor products I have never replaced one. The only problem is they are real heavy since they are loaded with real copper and the magnet structure has to be seen to be believed. Plus being such a good quality motor they can be tuned with the proper selection of capacitors. IE I can put a probe on it and tune the motor for maximum efficiency. Just love Baldor.

BTW FanHandler or Opto. I usually hang one of these on one switch leg just in case I want to go automatic. Or at the main house I let the computer select. I do not mind fliping switches at camp but not in my own home. LOL

Etaz... I just realized that if you posted your question in the heating and cooling forum it would have probably been answered in one or two posts... Have you tried putting it there? http:hvac-talk.com

Quote:

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Originally Posted by Missouri Bound

Etaz...I just realized that if you posted your question in the heating and cooling forum it would have probably been answered in one or two posts....Have you tried putting it there? http:hvac-talk.com

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Actually I went there first. But after getting a user ID and signing in, THEN I read their site rules... NO DIY.
So, yeah, I could've dragged 'em through it pretending to be a HVAC contractor or maint tech but I thought better of it and decided to wear my true green colors and just out right admit I am DIY and seeking compassionate experts. ;-)
Besides, you guys seem to be having fun with my "puzzle" and obviously are passionate about your trade.
I like to think I made the right choice.

That was one twentieth (1/20) of a horsepower. Not 1/2 HP from a pic of the nameplate.

This was interesting:
Index of /download/thermostat

Can't get their website to work. Interesting, but leaves MANY unanswered questions.

It looks like this stat will do what you really want to do except it's 24 VAC: Buy Honeywell TB7100A1000 MultiPro Commercial Thermostat | Honeywell TB7100A1000

It can be configured as two pipe with sensor and does the variable fan thing and is programmable. So, I think it satisfies the control creiteria.

Now all we have to do is find the gizmo that does the conversion from 24 V control to 120 V control. I think the transformer and three relays (probably 4) is available pre-packaged. Just have to find it.

Here is the other part (transformer/relays):

http://customer.honeywell.com/techli.../95C-10811.pdf

May or may not come with the Snaptrak. Snaptrak can mount on DIN rail.

At this point:
1. Need to double-check that it will work
2. Need to see if Honeywell as a 120 V version of the stat
3. It may not be DIY
4. Have to find where to purchase the 95C-10811

1. Didn't double check yet
2. No 120 V version
3. Your call - is it DIY?
4. It's going to be an HVAC supply house only item. Some aren't friendly to DIY's. Honeywell sells this product to consumers through contractors.

So, Etaz. You have 3 possible solutions:
1. The use any stat that looks ugly with no info.
2. The stat with the 3 speeds that looks like it will work. I'd ask whether the fan has to run all the time before committing.
3. The Honeywell approach. Seems to have all of the correct bells and whistles. Needs a second glance.

KISS,
I'm online now, gimme a few minutes or so to put some dinner down and will get to your answer. Thanks for yhour continued interest.

Ok, I procured a comparable model to the one I mentioned earlier but it is not auto-changeover.I got a great deal ($65 for either model) I can get the auto-changeover by 12/22 (backordered) .
So let's work w/ that one and I would LOVE to get the auto-changeover to work for the end product. So, let's start w/ what I have. Whaddya think?

Link to model procured.

Do you own a multimeter?

No but I can get one from home depot or menards. Always wanted one anyway.
I am sending you the PDF for the model via email addy.

One thing I noticed about this model vs. auto, The housing actaully prevents you from manually switching to AUTO. So, with housing off, I can switch to AUTO, are all the hardwaire pieces there and active for AUTO to work? Or does the mfr actually disable the AUTO feature at the firmware level or some other way? Just curious...

Just to let you know... I know my way around the electrical. I have put in hardwired undermount lighting and added 120v receptacles and switched outlets here and there so I am not completely green. I am comfortable with the fuse box and have mapped out the ckts... am doing a kitchen remodel in the coming weeks so had to sketch all out.

How is $53 for quantity #1

Patriot Supply - CONTROLLED AIR SYSTEMS INC Products

What was the exact model purchased?

Do you have a real instruction manual yet?

The mfr didn't answer my email.

I really need to know how the fan operates.

The manufacturer is here: http://www.controlledairsystem.com/p...mable_fan_coil

Nelson Bender designed the first Accustat. He is the president of Controlled Air.

I'm not happy with the website.

Etaz:
Do you want to pursue a 24 VAC solution or keep things at 120 V. This product seems similar to the Honeywell product. Relay Boards

Honeywell uses snaptrack and I LOVE snaptrak.

I just HATE when mfs forget to list essential s*it like size and type and size of terminations. You get into a project and find it need 0.110 fastons instead of 0.250 or #10 lugs rather than #6 lugs. Baaah Humbug.

Do you think I can find a job that lets me look at stuff for the first time and point out missing ESSENTIAL information?

WHOA! You da man. Ok, we'll just consider this our lil' sandbox here with this one.
Yea, I have the instr manual. WIll send you the page for the wiring.
What else can I do about the fan? Were you able to read the lable from the pic? Unfortunately, I don't have any other data for the outdated POS (better not let it hear me say that because it just might decode to stop working). Monday I can track down a mainttech and ask if they have any diags for the unit models.

KISS,
Of course. 24V AC was always the intent because of options. Keep in mind though budget. I don't mind adding relays and such, just have to keep bottom line in check.

Wiring and "How the fan operates". If it's on continuously, then it's a no go.

Monday try to track down a Honeywell W6380B Fan Relay Center so we can leave Sparky where Sparky belongs.

Not sure what you mean by "on continuously".
It shuts off when it reachs it's setpoint temp. Lil confused here.

Whatchu talking about? Sparky? The fan or the stat? Guess I should go drinkin' instead of horsin' around with Sparky.

How does this sound:

Get about 5 LED's and five 2.2K 1/2 watt resistors, 5 1n400x diodes (x=1 to whatever) and the cheapest 24 VAC transformer you can find.

Connect the diode and led and resistor in series. Put it across the 24 VAC. If it doesn't light, turn the diode around. Now wire up the stat so that low, med, hi, heat and cool are now lights on the "bench" and "see" what happens.

If it appears it won't work, then you can send it back.

You could use a breadboard or solder the LED string together and use heat shrink.

FAN: A lot of the stats I looked at reverted to a continuous fan when the temperature was satisfied. With hot and cold valves, this is possible to ventilate the stuffy motel room. If the stat does that, IT Won't WORK!

IDEALY it should change fan speeds based on the difference of desired temperature and temperature. The Honeywell does.

SPARKY: A name given to electricians, particularly ones who mess up. Keeping Sparky where Sparky belongs basically means make the tstat wires low voltage which minimizes possible damage. Cost increases. Safety increases.

MAGIC SMOKE Not covered yet.. But Magic Smoke makes electronics work. To prove it, once a piece of electronics smokes it eases to work. Therefor Magic Smoke is the secret.

PROPOSAL #1 would be re-worked slightly to use 24 VAC control wiring. Thus safer. It also opens up the possibility that the Honeywell stat can be used. It's up to you. I'd add an LED light to indicate the cool state of the changeover switch.

J-Box We need to find a relatively shallow box, guess 4-6" tall that will fit nicely in the FAN COIL that will house the new stuff. We need to know heights and size of the stuff. It will also need a few bushings.
Professional and not sloppy.

In order to assemble this mess, I was thinking of a small enclosure and grommets to pass the wires through. We don't know the sizes, so don't order it.

9x6x5h
http://www.newark.com/bud-industries...ty-cabinet/dp/

Snaptrak is here: Catalog 126 | Newark.com

and you need the clips on the next page to mount the Honeywell thing if it doesn't come with it.

Bushings
I was also looking for these the nylon bushings on the right top. http://www.keyelco.com/pdfs/M55p120.pdf

Then a small piece of DIN rail: http://onlinecatalog.digikey.com/Web...PageIndex=338#

and you have the basis of the project, or at least the idea so things don't get messy.

In the ideal case, you bring the cables in to their own terminal and branch from there.

So, you have motor (5), Sensor (3), Stat (7 or so) and power.

That and a couple of relays.

That's why the project is mechanical as well as electrical. You can easily change things around and the parts are reuseable.

Ah, Magic Smoke... installed at the assembly factory, and once it escapes, it can't be put back in...

That is why it is always good to have a box of magic smoke control handy. The box contains the same parts that you were working with but the smoke is still inside the parts waiting to be released on the second try.

Advances in technology are leading to the availability of smoke color options. Exciting!

Kind of like the smoke I used to put down on the landing zones to tell of possible evil enemy in the area so they would know if we were hot or not..

I always insist on genuine "Magic Smoke"... some of the cheap imitations do not perform nearly as well...

How do you determine if the Magic smoke is authentic? The destructive "smoke test"?

I will never forget the time Sparky was wiring the thermostats on a union job (I had no choice but to let them do it). When all was done I gave them the privilege of turning on the main power to activate the unit. I told the sparky that did the low volt wiring to go stand near the thermostat just in case we need to shut it down. When the power was hit the fun began. Each Honeywell 2 stage heat and cool got just a tiny glow and a nice little puff of smoke. Those were the heat anticipators going out. It cost the company doing the electric wiring 4 of those thermostats. BTW they let us wire them in the next go round. That is one of the storys I always tell the class.

You guys are too much. Glad to see this my forum is a vehicle for reminiscencing Sparky memories and conversations on where good "magic smoke" is harvested.

Kiss, I have come to the inevitable decision to take my mess and all this forum's experts' suggestions to a local reference. I have indeed learned a lot and acquired uselful resources that you have supplied. Carry on and thanks! I'll let you know how I get everything ends up... sans magic smoke (hopefully).
Cheers.

Sometimes we need a diversion. You shouls see some of the threads that we end up talking to ourselves.

If you can, can you scan the entire manual for the T202 stat. I'm very curious as to how it's supposed to behave.

I'm not sure what a "local reference" is. Can you elaborate.

Looking at how the cover is designed, you may just be able to insert the required relay etc. on a DIN rail on the side. A few stategicly placed cable clamps should work fine.

Just connecting the N, L1, L, M and Hi connections, the stat should work EXCEPT there is a possibility that it can blow the wrong desired air.

Two relays and some re-wiring will fix that. A relay with a coil LED would aid in troubleshooting. e.g. tells you when the loop temp changed. You would just move the sensor wires going to the stat and make them heat and cool going to the fan coil.

A 24 VAC solution for safety is possible. Adds cost. Would be useful if you were thinking about changing the stat.

Finally the Honeywell stat is EXPENSIVE and is 24 VAC, but adds the following desired features:
1. Thermostat indicates if cool or heat locked out
2. Automatically varying the speeds makes it function somewhat like a VAV ( Variable Air Volume) control system.
Once you have experienced a system that controls the fan speed automatically ambient noise is reduced considerably and your not awakened in the night with a high blower speed.
3. You get arm chair programmability as a value added option (big whoop)

Fan Coil systems are either hospitality based or institutionally based. From a marketing point of view programmability has little value. It would appeal only to codo owners like you. The hotel industry has different requirements (occupancy detection, window open, Leave for a while) etc. Any other application requires a building automation system so that the owner of the heat/cool plant saves money.

There is no incentive for the condo association to undertake a large upgrade because they just pass the costs onto the condo owner. The condo owner's get the short end of the stick.

You have a budget to contend with. You have options now where their didn't appear to be any. You'll get lower temperature for sleeping and repeatability for setting the stat. Bet you have a small mark where the dial goes.

I enjoyed this. Controls are a specialty of mine.

I'm working on one myself which is messy. But I'm in no hurry to complete it. There are options and I haven't ruled any of them out. I need to force a damper open at a about 1:00PM for about 10 minutes when Carrier does it's daily filter test and control that damper with a stat otherwise. The ease of getting into override for about 8 hrs is what I need. Precise control, I do not. Damper closed at all other times except when controlling or in test.
Just not there yet. Collected most parts. Tstat register damper and control box, transformer and one relay.