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    Mercury control replacement (14 Posts)

  • burnamon burnamon @ 9:28 AM
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    Mercury control replacement

    Am looking to replace an old Minneapolis Honeywell L428B3X1 aquastat and am thinking I could use a Honeywell 6006A but am not sure
  • Tim McElwain Tim McElwain @ 4:38 PM
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    What is it being used for?

    Is it SPST or SPDT? The L6006A is a SPDT but can be used to replace SPST by wiring to R - B (Normally closed opens on a temperature rise) used as High limit, Low Limit or Domestic aquastat, or R - W (Normally open closes on a temperature rise) used as a circulator control.

    The L428 is a series 40 - 120 volt control so the 6006A can be used to replace it.
  • burnamon burnamon @ 10:53 AM
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    SPST/SPDT

    Am not sure what it is. Believe to be the high limit. There is another old Honeywell aquastat L84ZA control on the tankless sidearm. Have thought of removing them both and installing a L8124A
  • Big Ed Big Ed @ 1:35 PM
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    Dual Aquastat

    L4081 is an replacement but you will need to change the well . I don't those well adapter kits are still around ... They kinda sucked anyway ... The old control is a helix probe
    I have enough experience to know , that I dont know it all
  • Big Ed Big Ed @ 1:37 PM
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    Dual Aquastat

    L4081 is an replacement but you will need to change the well . I don't those well adapter kits are still around ... They kinda sucked anyway ... The old control is a helix probe
    I have enough experience to know , that I dont know it all
  • icesailor icesailor @ 9:13 AM
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    Replacements:

    As shown in the photo, it looks like a SPDT or two STDP's. One is a high limit, to the left, the other to the right, is an operator that goes to the tankless to keep the boiler hot.
    On old hot water boilers with a tankless, we always used 2-"A's" and 1-"B". Two 6006A's, one as a high limit, one as the operator to the tankless connected to the thermostat to start the boiler. The other "A" shut it down in high limit. The "B" "Break on Fall" would stop the circulator(s) when the temperature dropped when the operator closed and started the burner.
    You'll have to keep the control that goes into the tankless working or you won't have any hot water. Unless the tankless is no longer in the circuit. Then, its another issue.
    As I remember.
  • Big Ed Big Ed @ 1:38 PM
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    look closely

    I remember that control , the upper makes on temperature rise, it's a B for the circulator the other is the A for winter limit.. They were used in the era of the series 10 summer and winter control that was installed in the side arm , Can't remember the number , top lever hozontal control with a switching relay .....
    I have enough experience to know , that I dont know it all
    This post was edited by an admin on March 16, 2014 1:41 PM.
  • icesailor icesailor @ 6:44 AM
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    Series 10:

    The only thing I remember about Series 10 controls is that they were 3-wire on the low voltage, Red, White, and Blue. And if you changed it to a 2-wire thermostat, you used the Blue and White. If you used the Red and White, it wouldn't run. Especially if you ran it to a RA-117 stack switch. You remember, the ones that could fail in such a way that even if they didn't get ignition, they could keep running and pump your oil tank dry into the combustion chamber.
  • Big Ed Big Ed @ 9:59 PM
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    Old Crap

    I was introduced to ... The R powered a heater in the thermostat which you can change the disks to give you different cycles on the thermostat which was a big thing converting from coal to oil with huge radiators . The heat anticipator replace the disks, now we can just program ..

    The RA117 before that was the Mercoide with mercury tubes which lasted forever but was loaded with brass and you can cash in on the mercury too back then and it was slow as Kansas ... Yes if the the motor clapper welded shut on the 117 you would loaded the boiler if you had a low voltage limit . . The ing clapper had to pull in first , the side points on the clapper made the motor clapper ... We use to replace the helix and clappers out in the field and clean the points with files and coat with #2 pencils
    The first ones where three wire for the series 10 thermostats ... Those old heat sensor controls where so slow action and easy to throw out of step . Yes that old crap .
    I have enough experience to know , that I dont know it all
  • icesailor icesailor @ 8:29 AM
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    Stepping:

    Oh the "Stepping" to re-set it. You knew that if it didn't re-start after hitting the reset, and you pulled it out to re-step it, you'd be back to change it.
    I read the instructions on how to reset the "steps". I could never remember if you pulled it out slowly, or pushed it in slowly. So, I always pulled it out slowly, then pushed it IN slowly. Then pulled it OUT slowly. If it didn't run, I changed it. I still don't know the proper sequence.
    You knew you lucked out when you had a no-heat call, you got there, and the burner was running, had been running for hours, and the tank was empty. That the burner stopped because of no oil. But the R117 didn't stop the burner, It would have flooded the space. A sigh of relief.
  • Big Ed Big Ed @ 7:48 AM
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    Cycle

    Pull it out to set start cycle ,push in to put set on run ...
    I have enough experience to know , that I dont know it all
  • icesailor icesailor @ 8:52 AM
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    Not to worry.

    Not to worry. If I ever see another one, I will do like the last one I saw. REPLACE IT. Can you even buy them anymore? Why would you want to?
    If someone was so cheap that they wouldn't be upgrading, I'd be wishing them health, happiness and long distance.
    Reminds me of when I was younger and I would get panic attacks over crawling alone under old crib houses and obsessing that the house would fall on me, I'd be stuck, and the boss wouldn't come looking for me until the next day when my wife had called him to ask where I was.
    I get almost the same feeling when thinking about those R117 stack switches.
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  • burnamon burnamon @ 9:15 AM
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    Thank You

    Thanks for all the replies to my original post of "Old aquastat". A lot of good topics here and useful information. Unlike the new technology these day I would rather see the older stuff. Give me a shellhead oil burner any day of the week. Nothing better than seeing them still out in the field. I remember when I first started my uncle teaching me how to clean the contacts on a stack switch with money. He always told me that the higher the dollar amount the more abrasive they were, Me being a kid I believed him.
  • icesailor icesailor @ 10:13 AM
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    Shellhead Burners:

    Shell head burners were a vast improvement over the flamethrowers that preceded them. But anyone today who sees one, if you don't know how it works or how to adjust it, rip it out and put in a modern adjustable head flame retention burner. Its the least you can do for a good customer.
    Any customer who wants to keep their Shellhead burner, needs to be wished health, happiness and long distance. Thank the Stars for 3450 RPM motors and Flame Retention burners. Like Carlin 100 CRD's. You almost needed sunglasses to look at the flame it was so intense.
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