Question about Honeywell Electronic Programmable Heat/Cool Thermostat - CT3300A100 Heater

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Replacing Round Honewell Mercury Thermostat

I wish to replace a round mercury Honeywell Thermostat (approx 19 years old) ... with a digital 7 day programmable Honeywell touch screen. I have oil baseboard heat with 3 seperate heating zones & each thermostat turns on/off my furnace circulating zone pumps only. I have 2 small wires coming out of the wall for each thermostat.

Above said ... What is the best Honeywell touch screen 7 day digitial thermostat I can use here ... I just want to plug in the 2 little wires & go ...

Thanks ... Kha

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Try to get one that is made for oil heat, the installation is easy only two wires, and the instructions make it easy.

Posted on Apr 26, 2009

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Honeywell programmable thermostat - was installed per instructions in manual and now the furnace runs non-stop unless I move switch to "off." The old (round mercury switch) thermostat was wired red t


If you are unsure about which wire goes where, that may be the source of your problem. The color coding can be confusing when changing from old to new. I pulled the instructions for my Honeywell CT3400A thermostat and found you can call Honeywell Consumer Services at 1-800-468-1502 M-F 7:30 am to 5 pm CT

Mar 11, 2013 | Heaters

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Programmable Honeywell


A Programmable Honeywell Thermostat is a great investment for you to make for your heating and cooling system. A Honeywell Thermostat will provide you with the best in comfort and dependability for many years.

Many people when they think of Honeywell Thermostats think of the old round T87 thermostat that has been one of the most common thermostats for years and years.

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Today they have those thermostats in designer colors and they are still made and used in many situations. But the manual thermostat is quickly becoming a thing of the past. With the rising costs of fuel the Programmable Honeywell Thermostat is becoming more and more popular. Programmable Thermostat Honeywell is even one of the most popular searches when it comes to thermostats.

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The VisionPro thermostat line has quickly become one of the leading digital programmable thermostats on the market to today. The ease of programming this thermostat and the touch screen interface has made it a very popular choice for many people. There is a variation of this thermostat for virtually any possibility that you can think of. The FocusPro line also is a very good choice at a bit less cost. There is a basic Pro line and also even a digital thermostat in the traditional round configuration. Both digital programmable and basic digital thermostats are available for line voltage control of electric heating.

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Along with the thermostats you now are able to add remote outdoor sensors as well as install you thermostat in a remote place and run a sensor to the space you are controlling. For many years these capabilities were standard for commercial thermostats, but now they are a very real possibility for home use also. With an outdoor sensor these thermostats now have the capability to turn off your heat pump and start you backup heat a certain preset out door temperature. In the past many systems have been installed with complicated electronic to do what a thermostat can do very easily.

The Programmable Honeywell Thermostat has come a long ways in the past few years. The changes have made this thermostat capable of doing many unbelievable things. If you are looking to replace your old thermostat, carefully compare the many thermostats on the market and then pick the one that will meet your needs the best. For many the Honeywell digital thermostat will be the best choice, giving them great flexibility and reliability in one thermostat.

http://www.fixya.com/support/r3894275-manual_honeywell_find_honeywell_manuals

http://www.fixya.com/support/r3623083-thermostat_wiring_terminal_designations

on Jan 15, 2010 | Heaters

1 Answer

I am replacing a 10 year old Honeywell Thermostat with a mercury switch with a new programable digital Honeywell OS#RTH7500D1007 MD 0638. There a 4 wires coming out of the wall and are installed on the old...


You are on the right track, you can hook the same 4 wires to the new thermostat without the jumper you had on the old thermostat. The jumper wire that is on the new thermostat can stay with no problems. Just connect the wires to the same terminals on the new one and your good to go!

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I just bought a Honeywell 5.2 Day RTH2300B Programmable thermostat to replace my old mercury thermostat for my gas fireplace. When I took of old thermostat it only has two wires. A white wire and a black...


I just installed a Honeywell 5.2 Day RTH2310B Programmable thermostat and I had to deal with the same situation: 2 wires, one white one black. After reading the edvice in one of the blog, the solution that worked for me was: BLACK ON Rc terminal and WHITE on W terminal. My furnace is running fine now. Hope it helps.

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My murcery thermostat is acting like a switch


Check to be sure the spring isn't binding in some way preventing it from moving freely. It is possible the mounting screws may be too tight deforming the plastic a little. Also be sure it is absolutely level. It is critical on the mercury type thermostats.

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Replaced mercury thermostat w/Honeywell CT87K - doesn't work!


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1 Answer

Honeywell round mercury thermostat - heat not coming on


If you tip the mercury switch so that it makes contact and the furnace doesn't start, it isn't the t-stat. Check the connections, then start checking the furnace.
In any case, ditch the mercury t-stat (recycle it properly) and get a new programmable one if at all posible. It will pay for itself many times over by turning your heat down in the middle of the night and back up by morning.

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1 Answer

Honeywell T86A3006 24V Class 2 Round thermostat 8020


The honeywell tradeline thermostat would work as a direct replacement (no mercury in the new ones), however if your using just heaters and no cooling system off of it, you could Heat only thermostat from honeywell that would replace your unit as well. Both at available at Ace Hardware with the heat only unity being roughly 7 dollars cheaper.

Jan 14, 2008 | Honeywell CT87B ROUND HEATING&COOLING...

1 Answer

Thermostat


anything that is in your comfort range. with the needle all the way to the right temp is at 90 or so. nothing happening? mercury tube inside isn't tilting and closing the circuit.

Dec 17, 2007 | Honeywell CT87B ROUND HEATING&COOLING...

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