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  • Rational SCC202G issues about top hot gas valve burner 

  • guest

    Member
    June 17, 2017 at 12:00 am

    The ignition and burner of the steam generator works properly and the burner below also but I have problems with the upper burner because after a few seconds it stops receiving 208 volts in the gas valve.

    the top and bottom burner hot air plus ignition electrode are new.

     

    Greetings to all the technicians

  • ectofix - Nashville

    Member
    June 17, 2017 at 3:24 pm

    So I guess it eventually displays GAS RESET, correct?  Is the top air burner blower running?

     

    If it stops sending 208v to the gas valve, then that’s happening because the ignition control is locking out due to a failure to prove flame.  This can be observed by doing a function test of the burner in the technician’s level of programming.

     

    Anyway, I’m not there to look at it with you, but the two most common problems I’ve had with those AIR burner systems are with either the ignition electrode or the ignition control:

     

    • Several times I’ve found the insulator for the GROUND ignition electrode will eventually loosen, slide over and enshroud the ground electrode’s tip.  As such, sometimes that burner simply won’t light…and sometimes it will have a delayed igniton (BOOM!).  It’s a flawed design which I hope Rational gets around to resolving.  Nonetheless, you said you replaced the electrodes, so that shouldn’t be your problem.
    • I’ve had the ignition module fail in some way in it’s operation of one of its respective burners.  In YOUR case, that module operates the STEAM burner and the TOP AIR burner.  The half of it for operating the AIR burner might have gone out.  For instance, it may not be sending a spark to that burner.

    There are various creative ways to test for problems with those ignition modules – which I won’t get into here.  But it’s possible that you’ll be needing a new ignition control module.

     

    I’m not saying that either of those are indeed your problem, but they’re the two most common problems that I’ve seen.

  • ectofix - Nashville

    Member
    June 17, 2017 at 3:49 pm

    I had asked whether the burner blower was running.  Here I’ve dug up an old post I’d made regarding that:

    Rational SCC Oven Burner Blower Issue 

     

    So…something to be aware of.  If you’ve tampered with those connectors at all during repairs, those wires (where they go into that plug) can be easily damaged.

  • rknauer

    Member
    June 17, 2017 at 7:00 pm

    Originally the burner gaskets were destroyed and dirt had been introduced into the hot air heat exchanger and therefore install new burners and electrodes.
    When placing the menu at the technical level I can independently check each of the burners and there is when I see the problem just in the superior hot air burner . Exactly the display shows “RESET GAS”
    In the place of inconvenience there are other units and I exchange the ignition module and I continue with the same.
           On Friday I communicated with  Rational   Technical   Services  they said it was advisable to check the gas pressure  (I COULD YOU EXPLAIN THIS) because any other gas equipment has the 1/8 plug in the manifold to be able to measure the pressure but in Rational I do not see this plug.
    The other thing Rational said was that it would corroborate the green light on inside the ignition module and it actually stays on.
    Other modern combi ovens  offer the possibility to erase the history of errors (SCCWE-202E) but in this model SCC202G I can not find how to erase.
    Anyway I’m going back to the kitchen with new ignition modules and harness.

     

                                                             thank you very much for your help

                                                                                                                      from NY 

                                                                                                                                     R Knauer

  • ectofix - Nashville

    Member
    June 17, 2017 at 8:05 pm

    The gas pressure test is through a built-in fitting on the gas valve.  It’s brass with a tapered end on it and has a needle valve in it.  You use a small screwdriver to open the pressure tap, then fit your gas pressure meter’s hose-end over it.

     

    You should do this test on the INLET pressure tap ONLY.  For natural gas, you want to read 7 to 11″WC.  Remember that the 7″ minimum should be met with this oven and all other gas equipment on the line calling for heat.

     

    Here’s a picture of the valve.  The INLET pressure tap is on the LEFT.  It’s a brass fitting.  There’s an identical one on the right.  Don’t use that one:

  • guest

    Member
    June 23, 2017 at 5:32 am

    Just a small addition. I have had the flame sensor wire, that is attached to the burner housing flange, become oxidized due to the heat from the flange. When this happened, the resistance in the wire going back to the ign module, went way up, causing a gas reset condition.

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