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IBC HC 20-125 Continuously heating the DHW for Indirect water tank

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kab7791
kab7791 Member Posts: 2
edited August 2022 in Gas Heating
Seems as if the zone for the indirect hot water tank seems to be continuously heating. Display says 171 degrees and code 6 for heating DHW. The DHW is set at 130 degrees and the bottom light and the DWH COmfort/ECO button is lit. Never seems to shut off and stop circulating and heating the water in the tank. We're in the dead of summer so the only thing really making heat calls on the boiler is DHW. Anything I should check?

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  • GGross
    GGross Member Posts: 1,047
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    Check the water temp in the tank, if you have a temp gauge check that, check temp at faucets. If it's continuously heating at 171 eventually that tank will be close to the SWT so don't reach in with your hand use a thermometer. Determine if your tank is overtemp first before someone gets in the shower, though you hopefully have mixing at the showers to prevent scalding.


    The comfort mode on those boilers will keep the boiler temp maintained at the temp it will deliver when a call for DHW is made, it is possible that is what is happening however code 7 should be displayed if that is the case. Personally I like to turn stuff like that off, especially in the summer as it can create excess heat to deal with.
    kcopp
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,835
    edited August 2022
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    My first test would be to disconnect the wire that connects the DHW aquastat or thermostat to the boiler control. I'm not familiar with this particular boiler but it appears that the wire I'm referring to is connected to X4 connector at pin 9 & 10 where the low voltage wiring is all connected. This is the same connector that the room thermostat and the outdoor sensor is located


    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,835
    edited August 2022
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    Further research of the boiler I/O manual indicates that your DHW control can be of the ON-OFF aquastat type or a 10K thermal resistance sensor. There is no programing needed to change from one type to the other at first glance. This means that you could have a thermistor that changes resistance based on the surrounding temperature. If you have that type of sensor, be sure it is located properly inside the appropriate sensing well of the DHW tank. If you have the on off type switch then check that the temperature is properly set on the aquastat.

    Either type of temperature control device will stop the boiler operation if at least one of the wires are disconnected. I would disconnect both wires to pin or terminal 9 and 10 on connector X4

    Hope this helps
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
    kcoppGGrosskab7791
  • kab7791
    kab7791 Member Posts: 2
    edited August 2022
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    That was my problem. I don't have an aquastat on my superstor. I have a 10k resistance sensor and when I touched the thermostat wires it fell out. So it was at the edge of the welded tube. I disconnected the wires and made sure the sensor was bottomed out to end of the tube and uzed a zip tie to secure it from ever backing out of the tube again. Powers the IBC unit back up and all is well again and back to normal
     Thank you all for your responses.
    EdTheHeaterMan

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