Missouri Climatemaster – No Signal to Accessory Relays

Discussion in 'Maintenance and Troubleshooting' started by Pump>Dump, Mar 29, 2022.

  1. Pump>Dump

    Pump>Dump New Member

    I have a Climatemaster Tranquility 30 Digital (TE) Series IOM with ATC32U03 communicating thermostat. I has worked perfectly for 4 years. The modulating valve works well but now is passing a small amount of water through, even when closed.
    Until I replace the modulating valve, I installed an inline 24VAC slow opening & closing valve between the furnace and the dump well (on the water leaving the furnace). Then, on the DXM2 board, I set the S2 dip switches in the following configuration: #1 – ON, #2 – OFF,#3 – ON. All other dip switches on S2 are ON. Next, I wired the electric valve to N0 1 and COM on ACC1. This setup should open the valve 60 seconds before the compressor starts. However, the electric valve would not activate at all. I had to manually open the valve when the compressor started. I used a multimeter to check for voltage at NO1 and COM as well as NC1 and COM and found none. I tried the same for ACC2 relay, using the ON, OFF, ON for dips 4,5 & 6 and wiring the valve to N02 and COM. Same thing; no voltage there or on NC2 and COM either. I’ve read all information that I can find but am now stuck. I hope it’s a setting rather than the board. Thanks for any advice.
    DXM2 Mother Board.jpg
  2. geoxne

    geoxne Active Member Forum Leader

    ACC1 and ACC2 are “dry contacts”. This means there is no power at these terminals. They are relay switches that make contact depending on dip switch settings. You need to apply power to the switch to power your new valve. As follows:

    At ACC1 terminals-
    -Wire from R(24v) to Com1 (this supplies power to switch)
    -Wire N/O terminal to power zone valve with 24v when dip switch conditions are met.
    -The remaining wire from the zone valve connects to C(24v) at P1 Thermostat terminal to complete the circuit. DO NOT confuse this with COM at the accessory relay.
  3. Pump>Dump

    Pump>Dump New Member

    Thanks for the easily understood instructions. I followed each step and it works perfectly! I am grateful for your expertise and willingness to share it.
    The new electric valve will assist the leaking modulating valve until I can replace it. With well water and a 60 PSI cycle stop valve, it started leaking in 4 years.
    I guess it was the turbulence and particulate matter that wore on it. An entering water filter plus a 20 lb pressure reducing valve on the exit water may help? Thanks.

Share This Page