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A question to the munchkin folks

I am replacing a GV boiler that has rotted out (my fault as I was running an undersized boiler with an out door reset to try and get the most efficiency as possible I can give you more on my theory of why and undersized boiler can save money)and thought I would try a munchkin, I all ready have a Weil Mclean DHW storage tank. Its the 46 gallon one that has a built in thermostat/aqua stat.

So I am installing a 140 munchin with the vision pac on it.It seams the munchin is designed to work with the superstore DHW tank and it seams the super store has a place for the probe to be inserted into.I was thinking I would just insert the probe from the vision pac in place of the probe already installed in the Weil Mclean storage tank. I removed the thermostat housing on the Weil Mclean storage tank and removed the aqua stat and found that the probe goes all the way to the bottom of the tank.The probe that comes with the vision pac has about an 18" lead so its seams if I install it I will be sensing the top of the tanks water Witch would actually be reading higher then what the water actually is in the tank.I think I could add some wire to the probe and let it settle down to the bottom of the tank where the other one was, Does anybody think this will be a problem. A couple of the fellow from my company had went to the classes on this system but I missed the class as I was away for fireplace training.

I have been reading the dislikes of the munchkin from some of the folks here, But I agree with the boilers theory so much that I just had to try one in my own home.

Any and all advice is greatly appreciated


  • chuck shaw
    chuck shaw Member Posts: 584
    You will be ok


    If you wish to use the probe, that will not be a problem, I would try to get it down to the bottom of the well in the storage tank. Take the extra time to solder the wire, and shrink wrap them, that way you wont have to worry about a wire nut fitting (or not fitting) in the opening. If you wish, you can use the mechanical aquastat that comes with the Weil-McLean tank, and just hook it to the two blue leads. At this point, you would loose the ability to set the temperature from the control pad. You would only see a 1 (for on) or a 0 (for off) on the status menu.

    I have heard, that the tank-in-tank design works really well with a condensing, modulating boiler, but I have not tried it myself, but I have had great luck with the Weil-McLean tanks in the past.

    Hopes this helps,

  • radmix
    radmix Member Posts: 194
    Weil Mclain

    I use these tanks all the time with the munchkin. make sure the senser is at the bottom of the tank. I use butt splices for my connections.
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