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Argo AR842 Relay Chatter

I have a 30-year-old Argo AR842 with HW Priority, connected to a Buderus boiler and an Indirect Water Heater. A few years ago and perhaps after minimal water exposer, on rare occasion I would hear some relay chatter. I changed out the arcing relay and noticed another relay occasionally arcing. At this point I am easter egging the problem and to no avail. I was wondering if my power stealing thermostats and system age are producing this issue. Since the system is 30 years old, I am hesitant to replace the box, knowing that is a few years I will be replacing the entire system. Trying to understand if a voltage drop or old PCB mounted transformer is the culprit.


  • Big Ed_4
    Big Ed_4 Member Posts: 2,687
    edited January 16
    Is the voltage coming is in range ? Yes ,you can get chatter from one of the thermostat circuits . Any changes with that ?
    I have enough experience to know , that I dont know it all
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 7,509
    edited January 16
    Are the power steeling thermostats also 30 years old?
    If the power steeling thermostats are more recent, then I would ask if the chatter start around the time when the thermostats were replaced?
    When I would Quote on a new system, I always like to quote all new controls and zone valves or zone circulators (depending on the system) and thermostats. that way i never have the argument about charging for a new thermostat or zone valve or whatever, during the warranty period, because it was not included in the price of the boiler job. So I understand your apprehension over buying a new zone relay panel only to have it replaced in a year or so.

    You have 2 options, put a dumb thermostat on the problem zone(s), or get the new control that is compatible with the power stealing thermostats. If it is only a year old when you get your new system, the contractor may discount the job by an amount that will reflect the cost of the control. If the control becomes a problem during the new boiler warranty period, then you will just have to pay the difference if and when that happens.
    Edward F Young. Retired HVAC ContractorSpecialized in Residential Oil Burner and Hydronics
  • OzoneSal
    OzoneSal Member Posts: 1
    Just fixed mine, Give me a shout