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Circuit board needed

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zepfan
zepfan Posts: 493
in Geothermal

Does anyone know of a generic circuit board that I can use to re control a mid 90's Hydro Heat geothermal unit. The main circuit board in the unit after thirty years failed and from what I can tell the company was acquired by Enertech, but most of the oem parts are no longer available.

I rewired it today so the customer would have cooling, however I am looking for a board that will provide lock out should one of the pressure switches trip, and freeze protection. I would also need the freeze sensor or freeze stat. The unit already has the pressure switches. I was hoping ICM or some other manufacturer makes one that I can use. Managing the pumps, reversing valve and aux. heat is easy, it is basically lock out, and freeze protection that I am looking for. Thanks to all

Comments

  • mattmia2
    mattmia2 Posts: 18,099

    might need to just get a couple terminal strips and wire it as a safety chain controlling a couple contactors.

    zepfan
  • 109A_5
    109A_5 Posts: 4,494
    edited September 10

    What is wrong with the original board ? There are places that can possibly repair it. Here are two examples

    http://hvac-circuit-board-repair.com

    https://www.upfix.com

    I have not used them, I do my own component level repair work. Often it is just loose connections (connector pin fitment), crimped connections, bad solder joints, failed relay contacts and/or bad capacitors.

    Have you looked on ebay, for a used or new old stock replacement board ?

    Other possible solutions.

    White-Rodgers 47D01U-843 Defrost Control Board Heat Pump Universal

    ICM2812 universal integrated furnace control.

    White-Rodgers 50M56X-843 universal single-stage HSI integrated furnace control
    White-Rodgers 50D50U-843 Universal All-Spark Ignition Module
    White-Rodgers 50F06--843 Universal Furnace Electronic Fan Timer

    Another idea is a small Programmable Logic Controller (PLC) or Programmable Logic Relay (PLR) (AKA known as a smart relay or mini-PLC) but solutions like that may become time consuming to set up and program.

    If you supply a good picture of the board (both sides) and the model of the unit, maybe a good picture of the wiring diagram, I may be able to come up with more ideas. Although information for a vintage unit may be limited.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
    zepfanAlan (California Radiant) Forbes
  • zepfan
    zepfan Posts: 493
    IMG_6702.jpeg

    thanks for the responses and information. Above is a picture of the board. I think it would be easier to go with a lockout board, because another contractor already replaced the original ecm motor with a psc so the motor control for this board is no longer needed, and the unit only does heating and cooling, no domestic water heating, or de humidification

  • HVACNUT
    HVACNUT Posts: 7,692

    Do you have a Johnstone supply near you? They can pretty much cross reference anything and find what you're looking for.

    Is it a split or package system? How old is it?

    zepfan
  • mattmia2
    mattmia2 Posts: 18,099

    that is a microcontroller with a separate external rom for some reason.

  • EdTheHeaterMan
    EdTheHeaterMan Posts: 12,745

    You know @zepfan, by LAW you can no longer operate that equipment!

    1. Hydroheat no longer exists
    2. Enertech bought the assets and intellectual property of GeoSystems LLC
    3. GeoSystems owned the HydroHeat
    4. There are at least three different companies involved here
    5. Enertech no longer supports that product line
    6. And there is nobody except you and a handful on HeatingHelp.com members that cares about helping customers since the 2020 Covid outbreak
    7. With the above 6 statements, the LAW of averages and planned obsolesence makes it against the LAW to operate that equipment.

    LOL

    That said, that circuit board looks impressive. I wonder what ti would take to forget about that and adape a different control system to that unit. the components are the same. Compressor, contactor, coils, reversing valve, temperature and pressure sensors, metering device.

    Maybe even take that system back to Analog relays and controls.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    zepfanAlan (California Radiant) Forbes
  • mattmia2
    mattmia2 Posts: 18,099
    https://forum.heatinghelp.com/discussion/comment/1903584#Comment_1903584

    most of the stuff on that board would be in a single ic with modern semicaonductors.

    Alan (California Radiant) Forbes
  • EBEBRATT-Ed
    EBEBRATT-Ed Posts: 21,026

    @zepfan

    Maybe this will work

    47d01u-843-instructions-en-us-1569852.pdf
    zepfan
  • 109A_5
    109A_5 Posts: 4,494

    Did you disconnect the AC power to the board ? Not even seeing the power cable.

    Did it have any sign of life when the power was connected ?

    Dead coin cells can render some designs inoperable. Test in circuit.

    Old UV erasable PROMs can loose their data.

    image.png
    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • 109A_5
    109A_5 Posts: 4,494

    Amusingly there is what appears to be a board for the same purpose but a later version on ebay. The seller claims it is in "In 100% working order" A bit pricey in my opinion. And some of the solder joints look a bit poor.

    HYDRO DELTA CORPORATION HB-02362DA VER 1.14 GEOTHERMAL CONTROL BOARD 12-026-100

    https://www.ebay.com/itm/206463695210

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
    zepfanAlan (California Radiant) Forbes
  • mattmia2
    mattmia2 Posts: 18,099

    i'd look around the linear voltage regulator for solder joints that broke themselves loose over 40 years of temp changes.

    zepfan
  • zepfan
    zepfan Posts: 493

    Thanks to all that responded to this topic. yes I did take the 24 volt plug off the board before this picture was taken I have decided to use an ICM 220 lockout relay and wire a freezestat,LP switch, and HP switch in series to the new board. I am also going to install a 24 volt light so the customer can tell if the unit is locked out. What it came down do it was cheaper to go this route then find a used board, and hoped it worked. Given the age of the unit, and the fact that is just for comfort heating, and cooling this seems the best option. Take care all

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