Thermostat help.
Hello. I was bored today so I tried upgrading my old Honeywell heat one mercury dial thermostat, looks like it was from the 70s. I tried replacing it with one of the newer Honeywell dial thermostats CT87N (heat and AC type). I was only connecting heat. On my old unit the only three Wire connections it had were R, W, and B. I removed and connected these wires to the new unit and when I turned it to HEAT, I heard the boiler fire. I have a heating oil system.
Problem is the heat never turned off when it reached temperature. If I turn the system off I hear the zone valve close. but as soon as I turn it on it’s all heat. I tried not using the B, but nothing turned on. I am hoping the is an easy answer but I don’t want to screw anything up, right now I am just using the off switch to control it.
I do have a picture of the old wires.
Thanks
Comments (13)
HU-178658043
4 years agolast modified: 4 years agoDavidR
4 years agoRelated Discussions
Burning thermostat HELP!!!
Comments (10)kframe, Thank you for your help, I wish I could tell you more...The brand is Totaline, though the house is 50 years old it is not the original thermostat as you can see it at some point replaced an old round one. It does control our air conditioner as well. I think that our heating is electric...I'm pretty sure. The whole thing has happened very suddenly, we never had a problem and then very quickly we had this overwhelming smell. The strange thing is that even though the thermostat stayed on through the night the smell did go mostly away until I noticed it again this morning. I have it off right now and in the 15 below temps we have now I'm concerned about the pipes if I keep it off...what do I do?...See MoreThermostat help please?
Comments (30)Weeds: Nah... "Since your picture shows 'Temp Hold', the unit is in Temporary Hold. If you press ^ or v to change the temperature from the program, this is a Temporary Hold. This only lasts for 2 hours and then it reverts back to the program temperature. I'm betting this is what is going on: the program is running and at 8am it switches to 62. After a while, you feel chilly and look at the display and think "how did this get changed?", you push ^ to raise the temp to 72 and the unit goes into Temp Hold. Two hours later it reverts back to 62, you get chilly and the cycle repeats. " I've long "felt" the two-hour default reset. This isn't what's going on. I have the thing programmed, and the display at least still reads that I still have it programmed, to go to 67 at 5:45a, 60 at 7:45a, 68 at 5pm, 62 at 9:15pm . If I override it at 10am from, say, 67-deg to 69-deg it will do what I say. But if I override it from, say, 67-deg to 70-deg at 10pm, it will not do what I say. It will reach 70-deg and then keep going, it will not stop. During the day it will reach the temp I tell it to hold at and it will hold the temp there. At night it will ignore the upper maximum. I cannot understand it, but this seems to be empirically what's going on. If you say somehow the factory default is being reverted to, what I cannot understand is why the thermostat override seems to work in the am but not in the pm. If, as I think you are saying, it is not my thermostat that is actually controlling things, but the default furnaces', then why is it seemingly "feeling" the override in the morning only? OK, let me try to unprogram the thermostat altogether ... I wanted to wipe the program clean rather than reprogram it to "nothing". But I'll try this instead......See MoreBosch Wifi Thermostat Wiring Help.
Comments (3)It appears you have wired the new thermostat correctly. How long does the blower run before the condenser kicks in? How long are you waiting between attempts of lowering the thermostat temperature in order to start the condenser? What might be happening in the new thermostat is the the G terminal is energized immediately which turns on the blower, and the Y terminal has a delay and energizes after a period of time. On most furnace control boards the Y terminal also turns on the blower. So as an experiment try disconnecting the G terminal and then lower the thermostat enough to turn on the AC. The blower and condenser should turn on at the same time. The clunking you hear is probably the condenser contractor closing. I don't see how changing the thermostat would affect the noise level....See MoreThermostat help
Comments (16)Here is the TX9600TS manual. You thermostat has a temperature swing setting feature. This allows you to set the cut in and cut out temperature delta. The default is 0.25 degrees, but it can be set as high as 2.25 degrees F. It is described on page 24, and how you can change it is described on page 26. Check to see what you setting you have. There are also additional settings that could cause the behavior you are seeing. Read the manual carefully. I suggest you make one change at a time and give it a day to see if has made an improvement. This is an interesting thermostat and it sells for $54 on Amazon. I don't recall ever seeing the swing feature on other thermostats, even those that are much more expensive. You may already have the best thermostat for what you want to do. The problem may be that at $54 it is not built as a precision instrument and it has limitations....See MoreHU-420739870
4 years ago
Ron Natalie
4 years agolast modified: 4 years agomike_home
4 years agolast modified: 4 years agoHU-420739870
4 years agoHU-420739870
4 years agoThank you all who commented. Mike I think this is exactly what I was looking for, i did some searching and I can clearly see how to wire this on an old CT87A thermostat it has the letters of my old wires and how they get wired in that model (W -> Y, B -> W). It seems like the heat only models are compatible with 3 wire zones. I just bought an Emerson model that states they support 3 wire zone to be safe, plus that one is programmable.
mike_home
4 years agoHU-420739870
4 years agoI bought this one https://climate.emerson.com/en-us/shop/1/white-rodgers-sku-1f95ez-0671
Model 1F95EZ-0671, said it was compatible with 3 wire zone value connections.
Seems like White Rodgers manufactures 3 wire zone values and Emerson now owns them. Here was the picture from the manual:
Now the only question is whether I connect the W-->W, or B-->W and the other wire to "6", guess there is only one way to find out.
mike_home
4 years agoHU-420739870
4 years agoStax
4 years agolast modified: 4 years ago
mike_home