OT will honeywell chronotherm T882A work with no transformer?

http://www.google.com/search?hl=en&ei=WMsvS7_cBcqLkAWIxIT2CA&sa=X&oi=spell&resnum=0&ct=result&cd=1&ved AgQBSgA&q=will+honeywell+chronotherm+T882A+work+with+no+transformer%3F&spell=1
The Thermostat reads:
Honeywell Chronotherm T882A 1054 1 The clock stopped working years ago and is not needed.
the Transformer reads: AT 75A 1036 2 OC 24V NEC Class 2 120V 50-60 CY 3VA
and it has been making a fairly loud humming noise for years.
Question: Could I just remove the transformer since I have no use for the clock functions?
The second item in the search above is a four page manual but it is also unclear to me - I know nothing except most thermostats do not need a power supply. I see no harm in just unhooking one of the two wires and see what happens????
Any suggestions? m
PS. This is all for a gas heated Carrier forced air heating and cooling unit in the attic.
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On Dec 21, 11:57 am, snipped-for-privacy@noplace.org wrote:

Well, first, you are certainly mistaken about thermostats and power supply. All thermostats need power. Sometimes it's internal to the furnace and sometimes you need to supply the power separately with an external transformer.
Second, I have never seen one of that type of transformer that didn't hum rather loudly. You might try remounting it directly to a wall stud, or other solid piece of framing so the vibration is not amplified by thin material.
Paul
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On Mon, 21 Dec 2009 15:03:29 -0800 (PST), " snipped-for-privacy@coinet.com"

A rental of mine has a gas wall heater without a fan and it only has a connection to gas and a thermostat. I guess the power comes from a thermocouple (???) and the permanently on pilot light. My notion was based on that.
m

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To specifically answer your question, probably not. Most electronic thermostats need the 24 VAC power to run their own circuit.
The furances I've serviced, the 24 VAC also opens the gas valve. So, if you take the transformer out of the picture, you get no heat.
But, it would be quieter. I suggest you take the the transformer out and try it for a couple days. Be prepared to put it back in. Let us know how it works, for you.
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On Tue, 22 Dec 2009 08:34:39 -0500, "Stormin Mormon"

24 V AC or DC? Will any 24 volt replacement that can output 3VA?

Or cooling I guess.

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A quick check of some similar Honeywell Chronotherm units shows the programmable thermostat section running off AA batteries and the gas valve section running off of the 24 volt transformer. If yours is the same, you will NOT be able to run it without the transformer.
Just disconnect the transformer, see if the gas valve come on ....... ever. You won't hurt anything.
You might check to see if your "hasn't worked for years" is due to no battery.
snipped-for-privacy@noplace.org wrote:

http://www.google.com/search?hl=en&ei=WMsvS7_cBcqLkAWIxIT2CA&sa=X&oi=spell&resnum=0&ct=result&cd=1&ved AgQBSgA&q=will+honeywell+chronotherm+T882A+work+with+no+transformer%3F&spell=1
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I'm sure you guys a correct - the 24 v IS needed to run both heating and cooling. It was only a hope of mine that I could do without the transformer - since after more than 30 years of service it is 'due to fail' any time. I was (am) somewhat confused about how or where I get the correct replacement. I did a google and that did not help.

It has no indication of a battery in the manual or on the clock itself.

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The furnace controls usually want a 24 volt AC output at 20 to 40 VA, try page 249 at www.grainger.com
In particular http://www.grainger.com/Grainger/items/4X744 for $15.52
I have several similar units for various circuits, NONE of them make a peep.
These mount to a 7/8" hole (1/2" conduit size) in the side of any convenient electrical box. It should be connected to the furnace circuit, AFTER the furnace shut off switch. When the switch is OFF, EVERYTHING on the furnace is dead. And the furnace should be the only thing on that cirucit.
snipped-for-privacy@noplace.org wrote:

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THANKS - you guys are the greatest - looks perfect.

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My search for the Honeywell T882A thermostat replacement was unsuccessful. Saw no info as to it being discontinued or what the replacement may be. What would be good places to search?
Thanks again m

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My search for the Honeywell T882A thermostat replacement was unsuccessful. Saw no info as to it being discontinued or what the replacement may be. What would be good places to search?
Thanks again m
PS I really do NOT need the clock feature.

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My search for the Honeywell T882A thermostat replacement was unsuccessful. Saw no info as to it being discontinued or what the replacement may be. What would be good places to search?
Thanks again m
PS I really do NOT need the clock feature. I DO need both heating and cooling. (I will eventually get it right)

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Sounds like you want a "Nonprogrammable, Mercury-Free Analog Thermostat" page 3820 at www.grainger.com The full deal Honeywell version with 'heat-Off-cool' is http://www.grainger.com/Grainger/items/1JUB1 for around $40 Any home store will have a similar equivalent for less $$ Grainger has the basic model for $22 http://www.grainger.com/Grainger/items/4PU47
The basic thermostat has 3 wires, adding the sub base with the switches for changing from heat to cool with change that to 5 or 7 wires depending on the options. You need to pull the existing one off the wall and check to see what wires need to be hooked up. The heat/cool changeover switch may be mounted somewhere else, you may not have the fan switch in your system.
snipped-for-privacy@noplace.org wrote:

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Thanks again Roy - fantastic information and source! m

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A lot of that is from researching hooking a modern microprocessor controlled furnace to an older multizone furnace control. Lets just say that they don't play well together. It looks like I will have to build my own custom controller. A microprocessor is the nifty way to go, reliability and maintenance considerations dictate relay logic. I can get all the functions I need with about 8 ice cube relays with 4pdt contacts along with about 3 time delay relays. Oh joy.
snipped-for-privacy@noplace.org wrote:

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four-pole double-throw (¦för 'pol ¦d?b·?l 'thro) (electricity) A 12-terminal switch or relay contact arrangement that simultaneously connects two pairs of terminals to either of two other pairs of terminals. Abbreviated 4PDT.
Had to look it up - Did you actually get it all to work as intended? Sounds like lots of effort and money with an uncertain outcome - that is if I were doing it. m

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4pdt relay has 14 contacts: 2 for the coil, 4 sets of 3 for the contacts. http://www.allelectronics.com/make-a-store/item/4PRLY-120N/4PDT-120VAC-ICE-CUBE-RELAY/1.html Picture about 8 of these, surface mount, lots of wire running around. http://www.allelectronics.com/make-a-store/item/MT14-PC/14-PIN-SCREW-TERMINAL-SOCKET/-/1.html
The guys at school want me to do a full microprocessor system but making changes in 5 years or having a real HVAC tech try to troubleshoot it makes me stick with relays.
New furnace is in, a LOT of tin bending (LOTS of metal content!), and the house is warm but the controls are not right.
Old system was 50's with a 60's retrofit o 3 zones on a forced air system. Old ductwork near the furnace was poorly installed, first 6 to 10 from furnace got trashed and replaced. Old furnace was installed before they put a new layer of concrete on the basement floor, had to hammer it out and pour a new concrete slab. Old zone dampers were simply huge bimetallic strips that got hot when you pushed 1/2 volt at xx amps through them, they got trashed.
I bought a 4 zone controller and modern dampers, had it ready to install with the modified ductwork. The zone damper controller is a "single or more" call system where any zone can call for heat, furnace fires up to respond. New furnace has MUCH better fan capacity than the old unit, MUCH more air. Some testing shows that I need at least 2 zones open or the system gets way overpressure. (You can hear the ducts bulging!) So I have to do a new controller that will open the calling zone PLUS select another zone to dump the rest of the air. Of course there is a different algorithm for summer and winter as well as time of day or even outside temp. Now to try and get some of my money back on the purchased unit.
Whole project gave me a new appreciation for the old foggies that could flop a 4'x8' piece of 26 ga sheet down on the work table and make up some twisted corkscrew piece of ductwork with nothing more than a straight edge, huge dividers, and a snips.
snipped-for-privacy@noplace.org wrote:

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They are usually fairly standard. Does the existing transformer say the VA rating?
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