Also if you look closely to your schematic you posted, the "W" wire to the gas valve has it's own limit, between the "W" on the board and the valve.
If you don't know what sites you post on, I have no desire to refresh your memory. You even posted one of those sites on a thread on this site.
You were wrong about the power to the thermostat being cut off when a furnace goes out on high limit. There is nothing in any furnace that turns off power to the thermostat due to a limit switch opening. My stating you are ignorant of furnace functions should be taken as positive criticism and not as an insult. The only thing insulting is posting things that are not accurate.
Training is important!
Practical Training is a must!
Also if you look closely to your schematic you posted, the "W" wire to the gas valve has it's own limit, between the "W" on the board and the valve.
__________________________________________________ _______________________
“Experience is a hard teacher because she gives the test first, the lesson afterwards" ~ Vernon Law
"It's what you learn after you know it all that counts." ~ John Wooden
"When the teachers become unteachable we're all in trouble" ~ Mr. Bill
"Remember "Pro" is only a name, it's not always a mindset determined to do everything correctly" ~ Mr. Bill
__________________________________________________ _______________________
“Experience is a hard teacher because she gives the test first, the lesson afterwards" ~ Vernon Law
"It's what you learn after you know it all that counts." ~ John Wooden
"When the teachers become unteachable we're all in trouble" ~ Mr. Bill
"Remember "Pro" is only a name, it's not always a mindset determined to do everything correctly" ~ Mr. Bill
The issues is not wiring in a way to keep the thermostat powered up, it's getting the furnace situation corrected since it's not operating properly. We don't want to "hide the problem" by wiring in a control circuit. It makes me wonder how many systems out there with battery powered thermostats are hitting the limit and the customer doesn't even realize it.
__________________________________________________ _______________________
“Experience is a hard teacher because she gives the test first, the lesson afterwards" ~ Vernon Law
"It's what you learn after you know it all that counts." ~ John Wooden
"When the teachers become unteachable we're all in trouble" ~ Mr. Bill
"Remember "Pro" is only a name, it's not always a mindset determined to do everything correctly" ~ Mr. Bill
Furnaces can still "work" even though they are shutting off on high limit. They run for a few minutes, go off on limit while the blower continues to run and blow hot air into the house. Once the furnace cools it resets and runs again. As long as it's not being used near capacity a homeowner may not notice this behavior, especially if the blower doesn't completely cycle off each time.
Pre-90's furnaces like you were talking about earlier that just cut the voltage from the gas valve while keeping the blower running would just keep working as far as he homeowner knew, unless they were hearing/watching the burners cycle.
__________________________________________________ _______________________
“Experience is a hard teacher because she gives the test first, the lesson afterwards" ~ Vernon Law
"It's what you learn after you know it all that counts." ~ John Wooden
"When the teachers become unteachable we're all in trouble" ~ Mr. Bill
"Remember "Pro" is only a name, it's not always a mindset determined to do everything correctly" ~ Mr. Bill
__________________________________________________ _______________________
“Experience is a hard teacher because she gives the test first, the lesson afterwards" ~ Vernon Law
"It's what you learn after you know it all that counts." ~ John Wooden
"When the teachers become unteachable we're all in trouble" ~ Mr. Bill
"Remember "Pro" is only a name, it's not always a mindset determined to do everything correctly" ~ Mr. Bill
Also, for any house that size that requires that little heat, just how much cooling is required. If that house is in an area far enough south to not need the least amount of heat that is available in a gas furnace, then a heat pump system would be the way to go, like is done in other Southern areas.
Since reg is refusing to give us specifics about the applications he is claiming, we have nothing to go on in order to find out why he has so many more issues than anyone else in the country.
Training is important!
Practical Training is a must!
Training is important!
Practical Training is a must!
This is all indicative of an improperly sized duct system, air blockage such as dirty filter or coil, loss of blower capacity etc. None of this has anything to do with the furnace being oversized.
What is the point of all of this rambling of yours? What are you trying to get at?
Training is important!
Practical Training is a must!
You know it's one thing to want to learn the trade, and just humble yourself and sit back and watch and listen, but when your argument is not fact, and you don't just stop for a moment to research something before you post, you not going to appear to be the brightest bulb in the house. It's like me going on a TV repair forum and and telling all the pro's there how a TV works or is wired.
__________________________________________________ _______________________
“Experience is a hard teacher because she gives the test first, the lesson afterwards" ~ Vernon Law
"It's what you learn after you know it all that counts." ~ John Wooden
"When the teachers become unteachable we're all in trouble" ~ Mr. Bill
"Remember "Pro" is only a name, it's not always a mindset determined to do everything correctly" ~ Mr. Bill
Please help me understand on the path to the 24V power to the thermostat. I've highlighted what I'm seeing on the power path, what am I missing? If LS1 were to open, how does it tell the CPU to go into "high limit" mode? The 24V powered thermostats definitely go blank and 24V to the thermostat back plate is gone when the burners go off on high limit and the "33 code" shows up. The blower continues to run while the 33 code is being displayed. Once the furnace cools back off the power is restored to the thermostat. I'd like to get to the bottom of this since I see a lot of them.