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High low boiler aquastat

Wayco Wayne_2Wayco Wayne_2 Member Posts: 2,472
We don't see many boilers with the tankless bundle heater around here, so I am not well aquainted with the high low aquastat that comes with them. I met one today and got confused. Can somone give me a simple sequence of operations to explain how it should work and the why's and wherefores. What does the differential do? Make it as simple as possible please. Break out the sock puppets if you have to. Thanks


  • Wayco Wayne_2Wayco Wayne_2 Member Posts: 2,472
    29 views so far and no replies.

    Is it really so simple that no one will comment? Or does no one know and the entire industry is clueless? I've been reading and think I understand. The high setting is for heat temperatures, the low setting is to keep the boiler at a temperature high enough that it can heat the tankless bundle. They both have a differntial of 10 degrees. The differential knob brings on the circulator but that's where I'm a little confuse. It's called a differential adjustment but differential from what? 
  • ChasManChasMan Member Posts: 459
    edited November 2009
    Tripple aquastat relays..

    Some models have more features than others.

    The basic principle is that there is a high and low limit which allows the boiler temperature to swing between those two values. The high limit setting is also the high limit safety.

    The diffential setting Is the amount of temperature drop allowed below the low limit that the boiler can drop to without firing when there is no call for heat.

    If there is a call for heat then the boiler will fire when it reaches the low limit. If not, it has to hit the low limit minus the dfferential.

    Thats the basic principle.

    I have a link to a PDF that teaches the basics. Its on another Heating site not sure if its allowed.

  • Wayco Wayne_2Wayco Wayne_2 Member Posts: 2,472
    Thank you

    That was just what the doctor ordered. The house in question has had a problem with the last room on the run getting warm. The circulator turning off might explain this problem. 
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