Wisconsin Nedd a 3 stage heating 1 stage cooling thermostat

Discussion in 'Maintenance and Troubleshooting' started by wisailor, Dec 7, 2016.

  1. wisailor

    wisailor New Member

    I am finishing up the install of my Geo system. I have a 5 ton Bosch water to water unit heating or cooling water in a marathon 85 gallon storage tank. I am using a Veridian delta t pump to circulate the water to an A coil that I have installed on a Goodman furnace. My heating and cooling currently uses the thermostat to turn on the circulating pump and fan on the furnace.

    I would like to find a thermostat that would incorporate the Geo as the first stage of heating and then the furnace as the second and third stage of the heating. When the the second and third stage are functioning I want the first stage to be off. I would also like the system to be able to switch to second and third stage heat when either the outside temperature is below a set point or when the power company turns off my dual fuel meter that runs the Geo when they have peak demands.

    I have contacted Honeywell and they told me contact a professional in my area. I work at a Technical College with an HVAC program and I queried the faculty with no success. I can create what I want with a PLC, I was just hoping to find a thermostat that would work.
  2. doctor15

    doctor15 New Member

    I know at least Trane 824 and Ecobee support this configuration because I've had both setup that way, but I'm sure there are much cheaper models.

    You don't actually need 3 stages. The geothermal HP gets connected as normal, then the furnace (both stages) is configured as Auxiliary. Just look for any thermostat which supports dual fuel

    I don't know much about this.. how would it communicate with the thermostat? Or does it just power off the geo?
  3. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    How is the warm water heating the space?

    Look at a PRO-1 #T755. 3 heat 2 cool. This stat allows you to delay 2 & 3 heat by time.
  4. mrrxtech

    mrrxtech Member

    WI Sailor,
    ebay has thermostats (see link below) most of which are used, making the price easy to deal with.

    I've bought several thermostats on ebay that have the Y1 & Y2 terminal for 2 stage Geothermal Units, plus normal heating, Auxiliary heating and Emergency Heating with electronic switch or manual switch.

    http://www.ebay.com/sch/i.html?_odkw=Geothermal Thermostat&_sop=15&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR2.TRC1.A0.H0.XTrane Thermostat.TRS0&_nkw=Trane Thermostat&_sacat=0#item465a428cd7

    The Trane XL500C is a good choice if you can find one at a fair price, like this one on ebay:

    Trane XL500C Manual, see page 9 for Aux & Emergency Heat selection:

    Honeywell thermostat 8000

    Zwave, Dehumidifier, Humidifier, 3 heat, 2 cool, Dual fuel


    List of Trane Thermostats on ebay:

    http://www.ebay.com/sch/i.html?_odkw=Geothermal Thermostat&_sop=15&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR2.TRC1.A0.H0.XTrane Thermostat.TRS0&_nkw=Trane Thermostat&_sacat=0#item465a428cd7

    The Trane Thermostat above is actually a Honeywell Taystat 500C that Trane put their name on. If you spend a few weeks watching ebay, you could pick one up for around $30.

    The 500C has temperature droop which is something most digital Thermostats lack. Digital thermostats turn the heat on when 1 degree below setpoint and back off when setpoint temperature is met. It's a bit annoying.

    There are plenty of Thermostats on ebay if you try doing several searches (Trane, Honeywell, Taystat, Waterfurnace etc).
    Last edited: Dec 10, 2016
  5. wisailor

    wisailor New Member

    The warm water works well until it gets below 15 degrees Fahrenheit.
  6. wisailor

    wisailor New Member

    Thanks for the info. I found the American Standard version of the Trane 824 on ebay for $149.99. I figured out how to have the system switch when the electric company turns of the power. I am going to use a relay and have the normally open contact connected to the outdoor temp sensor and the normally closed contacts connected to a fixed resistor that will give the tell the system that it is below zero. The relay will be energized from the 24 volt system on the geo heat pump. When the geo is running, it should use the outside temp and adjust accordingly and when the geo is not powered it should see a temperature below the outside temp setpoint and run on the gas. I should ahve it wired later this week.

  7. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    What is the heat emitter? How does the heat get out of the fluid and into the people?
  8. mrrxtech

    mrrxtech Member


    My Coleman Evcon Heat Pump uses an adjustable outdoor bulb type on/off thermostat that switches to gas heat when the outdoor temperature reaches the switch over point that I calculate and set in using electric vs gas graphs. I had to replace it once so I can probably find another one using the part number on the thermostat.

    Do you have a generator? When power is off there will be no 24vac to power up your system if you don't have a generator.
  9. wisailor

    wisailor New Member

    I am using a Enertech MCH060AST 5 ton Hydronic cased coil on a Goodman GMVC961205DN furnace. I am also in the process of putting in hydronic towel bars in the bathrooms and several hydronic radiators in rooms that need augmentation.
  10. wisailor

    wisailor New Member

    At this time I have no generator. I have that on the to do list and will probably happen in a panic.

    That is how life seems to go some times.
  11. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    I would use radiant as it is a better match to a water 2 water system.
  12. wisailor

    wisailor New Member

    I agree with you 100%, however when you are working with a 33 year old house, you are sometimes limited with your options.
  13. mrrxtech

    mrrxtech Member

    I once rented a Lincoln Log style home that was very cold in the winter. The owner used a small electric boiler with copper pipe routed around the 2 story building and into the basement. Each room had a small finned radiator for heating. The circulating pump was a Bell & Gosset pump that moved water so fast that the pipes would sing when the heat was called for by the thermostat. I pulled the Bell & Gosset Pump and replaced it with a Grundfos circulator pump to reduce the house pipe noise.

    A wood burning stove in the basement had a tank above the fire box that the house heating water was routed through allowing the house to be heated by a wood fire. The rate of flow wasn't critical, since the entire system was inside the house, and slowing down the flow didn't cause a problem with heat transfer to each room.

    If you routed 1' or 3/4" copper pipe through the house in a similar manner and used the same small finned radiators, that would be one way to get your Geothermal heat to each room of the house. The radiators looked a lot like those Baseboard electric heat elements used in electric heated homes.

    If you could find a wood burning stove with a water tank built above the fire box, you could use wood to heat the house if the power went out. Hot water would move from the wood burner, rising up to the 2nd floor (assuming you have one) then drop down to the basement or 1st floor by Natural Circulation.

    The house was so cold that I added a propane tank and put gas logs in the fireplace to try and increase the house temperature.

    I own a log house now but it uses the rectangular logs that are 6x10 inches so the logs provide plenty of insulation. The logs need to be kept warm on the inside to transfer heat to the outside which provides a thermal mass to keep the house from getting cold due to cold log walls. I use a 3 Ton Carrier 2 Stage Geothermal Unit with whole house duct work to heat the home. The previous owner used a wood stove in the basement, and a 1st floor fireplace to keep the house warm, with back up electric baseboard heat.

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