Honeywell Home CT87K1004 The Round Heat Only Manual Thermostat,Large,White,Large | CT87K1004

Easy to install, and simple to adjust.

Good thermostat and easy to hook up.

Had old 70 yr old type thermostate with mercury switch replaced it with this. It only had 2 wires a white and purple. According to instructions the white wire connected to r terminal and the purple to the w terminal. Been testing it out And seems to control the gas home furnace correct. To my surprize it went better and easier than expected.

This is NOT the reliable mercury-switched thermostat that Honeywell made for years. Instead, it is an electronic version made by a company called Resideo Technologies using the "Honeywell Home" trademark under license from Honeywell International. The instructions, which actually are well written, mention that the unit contains a Lithium battery. But there is no provision to test or replace the battery. This did not work out of the box, and I am returning.

See the review by John, 2-17-13 for an explanation of the (rare..) use of the 10+ year-life battery inside, as is there to 1) reset after a power failure and 2) initially after install: to charge up a capacitor which actually feeds the internal electronics and which is constantly replenished by the 24-28 V. AC power delivered usually by the furnace electrics when its own power is on (24/7.) Those 24~28 Volts A/C come via a small step-down transformer usually located within the furnace box. That said, recently I did have an -87K unit fail after some 4-5 years (I have no *reliable* info on the failure rates on the hundreds of thousands of these units in service, and individual guesstimates are useless/just gossip.) As I “do electronics” I naturally performed a necropsy on unit. The nominal 3 V battery in that was near-new at 3.22V on a Fluke prof. meter; it did not die via “battery failure”—see above, again—the few occasions where its small power input would actually be missed. I still wanted the natural simplicity of the glass-sealed mercury capsule, but I do realize that the mission of a thermostat/in 2018 is trivial to design and I Saw that the circuit board in my failed unit is comparable quality to that seen in prof. grade test equipment: so I was just unlucky in this early failure (most failures happen on initial turn-on, then ..during first days/weeks until: they go a long….time and then fail for complex reasons.) Four or so years IS … unexpected. Hence the 4-stars, pending.. I just bought another -87K unit from Amazon. It was a 3-second “drop it in and carefully press down till it latches” operation (no wiring had to be done.) I left it alone with temp turned all the way down for 5 min. or so: letting that capacitor charge up to its working voltage from the battery. While it’s only been a couple days, it is doing exactly what you want it to do: silently switch on the permission for furnace to take over. Note that: the manner/temperatures at which the furnace decides finally *to turn OFF* its blower motor is Not anything to do with the thermostat’s ON/OFF decisions: a variety of means are engineered within furnace controls to cover this so-called “hysteresis” time + temp process. Your thermostat is an ON/OFF switch ONLY. I’ll drop in and modify this report should this new unit fail shortly (unless, of course: many are already in caves, say? No reports then. No furnaces either.)

It works well. This is a nice improvement from the old mercury switch models.

ok

I really cannot comment on its quality other than to note it was a straight replacement for the one that was here. The baseboard hot water heating system malfunctioned and “may” have shorted the old thermostat and possibly this one. The only problem was that it required a tiny screwdriver (like those in eyeglass repair kits) to tighten the wires, which might be an issue for others without such a small tool. The temperature sensor is not sensitive enough, and the room stays about two degrees warmer than the setting. The "star" rating proved problematic. It is what it is—it's not better than the previous one and (in my opinion) worse without the little mercury glass tube that older models used for temperature readings. The heating system is a basic on/off two-wire setup that requires only a simple thermostat with an on/off feature, which would be very easy and inexpensive to provide. Sometimes all the bells and whistles aren't required to do a simple job that manufacturers feel the need to "fix" when there was no problem to begin with.

très pratique pour personnes âgée

It fit and worked correctly

We bought this in the spring for our shop but then it got nice out and we never installed it. Fast forward to fall, installed it….but then the furnace wasn’t working. Called a repair guy, he was thinking it was the valve on the furnace, tested, not the valve, tested the thermostat and its thermostat that doesn’t work. Yes our fault for not figuring it out sooner, but yeah wasted a lot of $$$$ both on the thermostat and on the plumber.

after having two digital thermostats only worked half the time I now get my but up an adjust the temp my self

I like the look of the product. I realized it does not work too late to try and return for a refund. What a waste of money.