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Train XL 80 - worked fine until yesterday

rob1969
rob1969 Member Posts: 2
Running a nest to control the XL 80, its only about 8 years old. The Nest first reported no power to the Rh wire. Swapped out the nest, same issue. Anything I can look at, as the furnace seems to be in a complete power down state. Circuit breakers seem ok.

Comments

  • pecmsg
    pecmsg Member Posts: 4,776
    Throw the NEST in the garbage. There garbage anyway.
    EdTheHeaterManSuperTechmattmia2
  • Jamie Hall
    Jamie Hall Member Posts: 23,168
    The Nest may or may not be telling the truth, but it would be well to check. Do you have power (24 VAC) on the wires coming to it from the boiler? No? OK. Go back to the boiler. Do you have power on those wires at the boiler? No? OK. Do you have 120 VAC actually coming to the boiler itself? Your grounds and neutral are good?

    No power at the boiler? Check for emergency shutoff switches that got shut off. There may be more than one, and they sometimes hide in odd spots.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    EdTheHeaterManmattmia2
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,720
    edited May 2020
    Is there a fuse on the control board inside the furnace? Look at where the thermostat wires are connected, sometimes that printed circuit board (PCB) is equipped with a 3 amp automotive-style fuse.

    Next Q. How long has the Nest Learning Thermostat been in use?

    Q. Do you know if the Nest Learning thermostat is wired with a common wire? There will be a wire connected to the C on the Nest Learning thermostat. The programming on the nest wiring screen will indicate if the Common Wire (C) is connected or you can look at the actual wires by pulling the Neat Learning Thermostat off the wall and look at the sub base.



    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    SuperTech
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,720
    pecmsg said:

    Throw the NEST in the garbage. There garbage anyway.

    Isn't it nice how others will tell you to throw hundreds of dollars away and truly believe they are helping you?
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    rob1969
  • Jamie Hall
    Jamie Hall Member Posts: 23,168
    I doubt that the Nest has anything to do with this one. The OPs comment that the boiler seemed to have no power is the fundamental problem here. So step one is find out whether power is even reaching the boiler in the first place, and if not, why not.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    EdTheHeaterManrob1969mattmia2
  • pecmsg
    pecmsg Member Posts: 4,776
    > @EdTheHeaterMan said:
    > (Quote)
    > Isn't it nice how others will tell you to throw hundreds of dollars away and truly believe they are helping you?
    N E S T bought the rights to the replacement for the electronic T87F after Mercury was banned. Honeywell realized power stealing didn’t work on several systems.
    Look it up yourself. N E S T has more complaints then any other stat on The market.

    OP

    Change the N E S T and watch your troubles go away.
    SuperTech
  • HVACNUT
    HVACNUT Member Posts: 5,804
    Could a switch have been turned off by mistake?

    The lower section door has a little spy hole. The control board has status lights. Green, Amber, and Red. Red being not good. Check the manual to the corresponding blinks, if any.

    As long as you don't see any Red diagnostic lights, turn the switch or circuit breaker off for 5 minutes. Then on.
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,720
    edited May 2020
    One can learn about the product or complain about the product. I have chosen to learn about the product.

    I believe there were Dead Men who said that these copper pipes will never catch on. And they died believing that copper pipes for boilers and plumbing will never catch on.

    Now we are past copper and on to PEX. I wonder what the dead men would have said about that?

    Just saying

    " I think thermostats with numbers on them are junk" at any price. What does a number mean anyway? 60° F at 90% RH feels warmer than 70°F at 20% RH! So how do we teach our customers that the numbers are relative to the humidity? Or should one just make then pay for a service call to tell them that there is nothing wrong and let them call again and pay again the next time the numbers on the thermostat don't match how they feel

    "Warmer <<< >>>Cooler"

    ...would solve many nuisance calls or we can just sell them a new thermostat for a couple of hundred and say the one they have is Junk.

    @pecmsg you have convinced me. I will throw my Nest Thermostat and cameras and smoke detectors and other nest products in the garbage. You have a persuasive way of presenting your self. I'm happy you were able to convert me

    @Jamie Hall I agree with you. except the Trane XL 80 is an 80% furnace... so there is probably a fuse on the circuit board.

    Still wondering how old the Nest thermostat is. 8 years (same as furnace) or more recent?
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,720
    A very knowledgable and experienced person posting here said, "Change the N E S T and watch your troubles go away."

    @rob1969 after you spend big bucks on a new wifi thermostat, if you still have the problem then, check the fuse.

    This is a normal procedure for most technicians in our industry. Go the large $ repair and if that does not work then look for something cheaper. That way we can make the expensive fix look like we were right, to begin with.

    I'm not a fan of parts changers. I like to find the problem before I fix it.

    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    mattmia2
  • SuperTech
    SuperTech Member Posts: 2,139
    I don't like the Nest thermostat either. I definitely get more service calls regarding them than all other thermostats combined...

    That being said, I would definitely make sure the fuse isn't blown on the furnace control board. Also make sure you have the common C wire connected to the thermostat and control board on the furnace.
    mattmia2
  • JacquesD23
    JacquesD23 Member Posts: 11
    Nests arent bad anymore. When they first came out they were a pain. Check for a burnt terminal.
  • HVACNUT
    HVACNUT Member Posts: 5,804
    edited May 2020
    Nest is good at hijacking threads though.


    @rob1969. Any updates?
    SuperTech
  • Jamie Hall
    Jamie Hall Member Posts: 23,168
    Nests are good at hijacking threads. And in this instance, I think that @rob1969 certainly has enough places to look -- without worrying about the thermostat.

    To clarify though, on my objection to Nests: first, my objection is not to the Nest, but to an entire class of thermostats which think they know better than the occupant how the system should be run. They sometimes do; particularly with fast responding heating systems such as forced air, which is what they were designed for and meant to be used with. Sometimes they don't, and have to be fiddled with to give good results. Second, I object to any device in my home which broadcasts what I am doing, when, and with whom to the world wide web.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    SuperTech
  • rob1969
    rob1969 Member Posts: 2
    Thanks to all of the positive comments and insight. my comment about the Nest is the system does not appear to have power. Hence the fuse potential issue. I will open up the unit today.

  • mattmia2
    mattmia2 Member Posts: 9,575

    One can learn about the product or complain about the product. I have chosen to learn about the product.

    I believe there were Dead Men who said that these copper pipes will never catch on. And they died believing that copper pipes for boilers and plumbing will never catch on.

    Is this why we have houses that were built in the 50's that have galvanized pipe even though it couldn't have been less expensive than copper even then with all the additional labor and they should have known by then that they would rust and fail but copper had been available for about 20 years at that point?
  • HVACNUT
    HVACNUT Member Posts: 5,804
    > @rob1969 said:
    > Thanks to all of the positive comments and insight. my comment about the Nest is the system does not appear to have power. Hence the fuse potential issue. I will open up the unit today.


    There will be a plug type 5 amp fuse on the control board in the lower blower section.

    That door also (should) has a door switch.
    Once you check/replace the fuse, you can check the status lights with the door off by depressing the switch. Just make sure all other switches and the breaker are on.
    Ceacel
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,720
    edited May 2020
    @mattmia2 You might be correct with your observation. I try to put myself in the mind of the original installer whenever I can. Maybe the plumber had a ton of galvanized pipe left in his warehouse when he got the job to rough plumb the home... so the new copper would cost more than using up dead stock.

    We are putting in a lot of condensing furnaces now-a-days. so what do I do with all the b-Vent in my tin shed? Repair the vent pipe for Trane XL80 furnaces maybe? But this is off-topic.
    :/
    I would certainly like to hear the resolution of PO's problem
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,720
    If it is a fuse... after you replace it, it may blow again. If so, you will need to locate the source of the overcurrent. I had a problem with the landscaper using a trimmer near the outdoor AC unit. The low voltage wire insulation was worn off and from time to time the wire would short circuit. The heater worked fine all winter. As soon as the AC was activated in the spring... pop goes the fuse. No heat and no AC.
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    mattmia2SuperTech