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  • Anyone else have problems with American Range A11105 thermostats losing calibration?

    guest created 1 year, 6 months ago 1 Member · 11 Posts
  • guest

    Member
    March 14, 2018 at 12:00 am

    These thermostats seem to also be known by the Manufacturer’s (Robertshaw?) model #KXT-466-36. Three in a row that I installed in an American Range AR series convection oven have all begun to run 100-150 degrees over the set temp, some as soon as 6 weeks after installation.

    These are not calibrate-able thermostats, and there is nothing wrong with the knob or indicator face plate…anybody else experiencing this?

  • fixbear

    Member
    March 14, 2018 at 5:32 pm

    Six of them?    A month and a half?    Doesn’t make sense.   I know they are a bit difficult to replace without damaging the tube or bulb.  And the bulb mounts are always a bit of a problem.  But what is the user doing?   Running at 550 all the time?  Slamming a pan into the bulb or tube?   And have you verified your digital thermometer?.  Did you add a pan of water to stimulate a load?  Some ovens will overrun empty.   BTW,  I believe that that thermostat is adjustable. But you have to have the proper tool and know both cut in and cut out. before changing. 

     

    Is the thermostat area clean and free of spills or steam damage.

  • ectofix

    Member
    March 14, 2018 at 5:46 pm

    I haven’t heard of that, but a manufacturer’s defect IS possible.

     

    Have you contacted American Range about this?

     

    What makes you say they’re not calibrate-able?  I see a calibration screw in this picture:

    American Range A11105 THERMOSTAT,KXT ELECTRIC M/MSD 

     

    Are you sure the bulb or capillary tube isn’t incurring some sort of damage – maybe due to how they’re being installed?

     

    These three in a row (as you said):  Are they in different ovens at different businesses…or all at the same location?

     

    Is there any indication of something like moisture or chemicals getting onto the thermostat body? 

  • ectofix

    Member
    March 14, 2018 at 5:52 pm

    Great minds think alike…

  • fixbear

    Member
    March 15, 2018 at 5:27 am

    Unfortunately we don’t have any idea as to our Guest skills or ability.  Robershaw KXT series are a old design and ussually quite reliable.  But being a snap action switch, they have a drift designed into them.  Most I have seen are about 50 degrees  But I’m certain they  make all different ranges.  We all know how a empty oven can overun the thermostat.  It’s not made to be empty.  Where you mount your thermistor to measure the oven has a big effect as well.  All ovens have hot spots  and a difference in temperature from top to bottom and corner to center.  Hopefully they are using a K couple wire and fastening to a rack in the middle. but the sensing bulb in the air. 

     

    Not knowing the oven model,  some of the Americans had the thermostat down on the left side mid oven height.  Prime place for spillage and steam.  Let alone running a cart into it.  Never did like that design.

     

    The only oven I ever came across that held temp within a couple of degrees was using a hydraulically modulated flame valve.  I can’t remember if it was a Franklin or South Bend.  The Navy depot in Scotia had 6 of them that later were donated to the BSA   Loved how the flame would go to just nubs as it got to temp.

  • guest

    Member
    March 17, 2018 at 5:19 am

    A hundred years ago, when many of the mfg were moving “off shore”, there was some quality control issues that caused problems with t stats. Its possible that they may have changed vendors. I would call Shaw and ask them. Some companies are not always forth coming when they have a bad batch.

    As above< I would look for bulb or capillary damage, first.

    On a related note, steam? I never heard of this problem and I have a few years doing this. Can someone school me on this?

  • fixbear

    Member
    March 17, 2018 at 6:29 am

    Four or six inch deep hotel or roasting pan full of product, but gains liquid during cooking to the point it is hard to remove from the oven without a spill.  They are not going to spill on them self’s and get a burn, so they spill on the oven door and front of the oven.  It immediately flashes to steam and penetrates the whole front of the range.  Now over time the controls accumulate dust, and grease.  Add hot steam to that and they migrate internal of controls and cause sticking or delayed action.  This is often seen on the American ranges with the side temp control.  It’s just the right height for a direct hit from a spill that goes right in the shaft area..  Mostly I seen this in volunteer kitchens.  They tend to forget that the meat contracts during cooking.

  • fixbear

    Member
    March 17, 2018 at 8:25 am

    Guest wrote:

     

    A hundred years ago, when many of the mfg were moving “off shore”,

    The foundation for that was the Ford administration.  However it was the Clinton that went all in and pasted NFTA and started the Far east sourcing. 

    As above< I would look for bulb or capillary damage, first.

    Exactly were one should look fist. Funny how the bulbs are always loose and hanging in ovens.  Then someone slides a pan in aggressively and OOP’s  My thermostat is off.

  • guest

    Member
    March 21, 2018 at 1:19 pm

    I’m the author of original question. As for my skill level, I may not even know how to use this forum!

    I’d say I’m an advanced D.I Y’er who has learned by asking real techs a lot of questions.

    Thanks for your input, I’m embarrassed to have missed the calibration screw on the AMRA11105 – I swear someone who supposedly knew more than me told me these were not calibrate-able.

    Steam and chemical exposure are unlikely in my case; the bulb being hit by pans, etc. is definitely happening, but has always been an issue in the restaurant I maintain…

    Thanks for responses and any further are welcome.

  • fixbear

    Member
    March 21, 2018 at 2:08 pm

    If you register,  You’ll get a email reply at every post.  Most manufacturers say to replace any T-stat that has drifted more than 100 degrees F. 

    Not sure about your oven bulb mounting location,  but most are in clips at the top rear where a pan will not come in contact.  That’s where the mounting of it becomes so important to longevity.

  • ectofix

    Member
    March 21, 2018 at 5:06 pm

    Rex, thanks for for the courtesy of getting back with us on that.  Most folks who come here don’t bother.  Feedback is always welcomed.

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