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  • Rational SCC WE 202G heat exchanger failures as well as several other component within 1st 3 years

     rationaltechnician updated 4 months, 3 weeks ago 1 Member · 8 Posts
  • guest

    May 23, 2019 at 12:00 am

    I am curious if anybody has had these same issues? I have had to replace 2 lower and 1 upper exchanger as well as a steam generator, all of the blowers, burners, electrodes, gas valves, pumps, solenoids and a main PCB. We had really hard water and have since added a water softening system but they both had popping issues even though I was keeping the flue gas dialed in. Any ideas why I have had all of these failures within the first 3 years of operation.? They do get a lot of use but so does our hospital to the north and they don’t have as many issues as us.

  • fixbear

    May 23, 2019 at 2:47 pm

    Has the software been updated?  Ectofix or badbozo would be able to help better with this one.  Cleaning and water quality have a efffect.   When was the last time a Rational tech looked at it?

  • badbozo2315

    May 23, 2019 at 2:53 pm

    By “you replaced”, I hope you mean you had a service company replace *under warantee* all those parts you mentioned, yes?


    And I’ll bet with that being a hospital setting, all the ones I’ve seen are left running (yes! running on steam mode continiously) or on standby 24/7. Without being idled during non-cooking times, those boilers will turn into scale-making masterpieces, regardless of what the manufacturer will say. And treating the water with scale stick type systems or water-softener systems doesn’t help much, and are not recommended by Rational. We’ve been through this on this site in the past and on The Other Site. If you can do it, a proper treatment system just for the boiler feedwater will do wonders.


    Have you turned down the btus of the burners in accordance with Rational service bulletins? They know they have problems with exchangers in long-running kitchens.


    Popping units can be a nightmare for techs, especially on propane, in my (direct) experience.


    And Rational pumps can be just annoying little critters.


    Finally, I’ve seen new machines have catastrophic failures right out of the box (on many manufacturers), so having hard-working units have issues over 3 years time would not seem out of the ordinary, from my experience. I realize it’s painful, but they are, as you know, complicated evil machines. 

  • tonyd

    May 30, 2019 at 7:57 am

    In My experience what you are seeing is only a little out of normal. Some questions though. The we units will delime their own boiler so soft water is not good as well. Watch a wash cycle with detergents. See how much bubbles you have building in the unit. It should not be building up over 6” high. If you do you need to harden your water back up or switch the unit to soft water. This will reduce the amount of failures you are having with valves and such.


    The popping sound your getting from the ignition system, be it hot air or steam. How long was the popping was going

     on? Was it violent at times? If so and this happened for a week or so, your gas valve is damaged and will not operate correctly. Good luck seeing it fail. I have seen low micro amps when I did catch it. I have 9 of these puppies and have had all the same issues.


    Once a week it is a good idea to shut them down for five min or so. This will allow the unit to reset itself. Every three months run a cal and it will show you any issues the unit may be having before it becomes an issue. Good luck and keep the cooling fans clean and working. My kitchen gets over 90 degrees and the boards do not like it. Lol.  

  • rationaltechnician

    June 25, 2019 at 12:19 pm

    I will add some things to those that have already been mentioned.  The question was not specific to only one thing so I will touch on all of them.


    From date of installation (the unit records this);

    Rational standard warranty since September 2011 is 2 years parts, labour and travel.


    Since January 1, 2013, Rational offered a 5-year warranty on steam generators including travel and labour for units Index G or later (approx. October 2008).  But read the small print.  You have the responsibility of supplying good water and preventing scale build-up in the steam generator.  If you are cleaning daily using light, medium, strong and/or , “save” (units produced since 2011); the steam generator will remain clean regardless of what the sceptics say.   Care control works when used daily and according to manufacturer’s instructions using their tablets.

    If you are replacing a steam generator on a gas model where the water enters the combustion chamber, your problem is not scale, you have aggressive water (e.g. high chlorine, chloramine, chlorides, and/or low alkalinity and pH).  In looking online, in most cities, you are good in getting a carbon filter that filters chlorine and chloramine as well as a 5 micron sediment filter.  This is the simplest of water filters and lower cost.  Don’t try to save money on this part, you will improve overall performance of the rational.  Our cities don’t treat water for equipment, they treat water so that it is safe to drink and prevent corrosion of their older pipes. They don’t take into consideration the effect it will have on your equipment.


    If for some reason you have high amounts of chlorides in your water, you are either ona sodium water softener or in an area where it leached into the water supply.  Unfortunately, reverse osmosis is your only option and then you need to add minerals to bring up your pH and alkalinity again (get water back into neutral).  Read up on the Baylis curve to understand the relationship of pH and alkalinity in regards to how corrosive your water is. 


    Hot air heat exchangers

    Someone already mentioned about recent bulletins so I will answer the warranty question.

    1st and 2nd year – repair covered including labour and travel

    3rd year – part only on heat exchanger

    4th year – 75% of part only on heat exchanger

    5th year – 50% of part only on heat exchanger


    The rational trained technician who is updated will change some settings on the unit and ignition electrodes.

    This should help eliminate popping.

    The rational burner system is a much more precision burner system than an open top burner which gets primary and secondary air.  Your supply gas pressure as an impact (even if you did not have problems before).  Natural gas supply pressure must be between 6.5″ and 10″ wc static and dynamic.  The pressure drop must not exceed 20% from static to dynamic.  Models 202 must have a minimum 1″ gas hose to handle the 340K btuh. (don’t go cheap, make sure it is a Dormont, you’re good for 7 years).


    Technicians who have worked on these units might get caught up on the heat exchanger problems and be in the fog about other potential problems.  Don’t overlook dust in the air supply hoses, burner blowers, failing gas valves and ignition modules.  You will be chasing your tail all day.  But I admit, not the easiest to diagnose down to in these cases.  Just check what you know and look for what is not within spec.


    Hope this helped and good luck.

  • ectofix

    June 25, 2019 at 6:23 pm

    rationaltechnician wrote:


    If you are cleaning daily using light, medium, strong and/or , “save” (units produced since 2011); the steam generator will remain clean regardless of what the sceptics say.   Care control works when used daily and according to manufacturer’s instructions using their tablets.

    Thanks for your input, rationaltechnician.  I read all of your responses to this and the other threads.  You definitely know your stuff on Rationals and took a good bit of time to write all that out.


    Yes, the tablets DEFINITELY work.  Our three newer units, all SCCWE202s, have survived their first three years of service with very little of my intervention.  I stay on the Chefs by constantly telling them their ovens require frequent and regular cleanings. 

    As for the little that I’ve had to do as an in-house tech?  The CDS readings (in tech level) and my own visual inspections confirm that there’s little (if ANY) scale within the generators.  Nonetheless, I STILL can’t let myself let it go, so I still manually descale them once a year…JUST to say it got done and so I can record that fact.

    ON THE OTHER HAND…j-u-s-t TODAY – I addressed the scale buildup within an old (95 model) CCD202.  A model built well before CleanJet and CareControl was invented.  It hadn’t been descaled in two years (another tech’s area of responsibility).  I harvested about three quarts of sand and rock out of that generator.


    That’s a fairly fair comparison of two heavily used 202 ovens where one gets maintained by the tablets and one does NOT.  So – naysayers be aware!  The Rational CareControl system and their Care tabs DO work.


    On another note:

    I just re-read the OP’s initial question.  He’d said that his steam generator had to be replaced.  That caught my eye.  WHY?

    Well, of my fourteen SCCs (including those newer WEs), I’ve had to replace exactly TWO steam generators, but I know exactly why they failed.

    Understand that those were in our newest ovens up until we got those WEs in 2015 & 16.

    Both ovens are a combi-duo set, so…located within the same kitchen (we have allot of kitchens).

    At some point, we discovered that the Chef-in-charge, who judiciously used the cleaning tablets to keep her ovens ****-n-span…was feeding the tablets into the ovens…BACKWARDS!  She was putting the RED tabs in the drawer and the BLUE tabs in the blower basket!

    Those tablets are two totally different chemicals designed for two entirely different purposes in the CareControl cycle.  The BLUE ones are a mild acid, used mainly for deliming the generator.  The RED ones are highly caustic and a strong alkali serving SOLELY (and quite effectively) to break down all the foodstuff adhering to the oven’s walls.


    We corrected that Chef’s maligned usage of the two types of tablets.  As a reminder, we showed her the animated graphic on the control panel’s screen illustrating where the RED and BLUE tabs go.  However, the damage was done:

    • Within a year of each other, BOTH steam generators failed (evidenced by water migration into combustion chambers).  So the RED tablets caused metal fatigue in the generator’s heat exchanger.
    • Sometime LATER, the blower baskets in the blower baffle rusted through and crumbled.  There’s also rust on the cooking compartment walls and pan supports.  So, the BLUE tablets caused failure of the stainless-steel’s designed resistance to corrosion.


    Make SURE the RED and BLUE tablets are fed to the oven PROPERLY.


    ONE MORE note:

    One of our prior in-house techs used to exclusively maintain ALL of our Rationals on property (he went to school on ’em).  He’s gone now, so I became that guy.

    There was something that HE used to do that I (as the NEW in-house tech at the time, coming from the field) specifically told him NOT to do.  He would add descaler (Cleveland’s “Dissolve”) to a generator (as you know, we frequently call the boiler)…and THEN – let it “soak” for a few days.

    I’m NOT LYING!


    When I left the field to go in-house, I TRULY did NOT know what I’d gotten myself in to.

  • ectofix

    June 25, 2019 at 6:59 pm

    ectofix wrote:


    …who judiciously used the cleaning tablets to keep her ovens ****-n-span

    Dear TechTOWN,

    Please forgive me, for I have SINNED.

    Image result for spic and span

  • rationaltechnician

    June 25, 2019 at 8:20 pm

    I always love these good stories.  But you brought some points I totally forgot of now that technicians are becoming more familiar with Rational.

    Great catch on the user errors.  We take these things for granted but forget sometimes it is new to others.

    A few more cautions.

    Never bake the detergents in the cabinet.  Instant chemical burn of the stainless steel.

    I understand there was a few Cleveland technicians that were told back in the day to leave the descale in there and sometimes even boil the descale solution.  Just like the medical industry, we have come a long way and realize some of these things were a huge mistake.  But I understand in extreme scale situations, it helped speed things up.  But never do it on a Rational.  I have seen the whole interior cooking cabinet corrode because of a veteran technician boiling descale in the boiler in addition to the other problems you mentioned.  This is where experience sometimes hurts us.  We can’t apply the same solution to everything.


    I love seeing the stories and I bet many here can learn from them as well.

    Good luck to all if your lucky enough to have a Rational or work on them frequently.  For sure my favourite equipment to work on.

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