--- title: "Deliming Steamers and Combi Ovens: Hard Water, Maker Intervals and a Descaling Cycle Step by Step" description: "What scale does to elements, probes and drains, how often Alto-Shaam, Blodgett, Rational and Cleveland ask for descaling, water limits, a SteamChef procedure…" url: "https://commercialappliancerepair.center/guides/deliming-steamers-and-combi-ovens/" date_modified: "2026-09-26" --- Maintenance and prevention # Deliming Steamers and Combi Ovens: Hard Water, Maker Intervals and a Descaling Cycle Step by Step Deliming steamers and combi ovens removes the mineral scale that boiling leaves on elements, probes and drains. How often depends on water hardness and hours of steam: Alto-Shaam asks for monthly descaling, Blodgett's BCX prompts after 30 boiler hours, and Rational's iCareSystem reports scale as it builds. Use only the maker's product and follow its procedure step for step. By [CommercialApplianceRepair.center technical team](https://commercialappliancerepair.center/authors/technical-team/) Published September 26, 2026 ## At a glance. Every gallon a steamer boils leaves its minerals behind. Scale grows on the heating elements, the water level probes and the drain until the unit heats slowly, misreads its water level or stops, and the makers treat removing it as the owner's job. Read the whole guide ### Blodgett's view of deliming The single most important preventive task Problems from insufficient deliming are not covered by its warranty. ### Cleveland SteamChef feed water Dissolved solids under 60 ppm, alkalinity under 20 ppm Poor feed water voids equipment warranties. ### SteamChef 22CET descaling time About 1 hour 30 minutes With the steamer left unheated while the descaler works. ### Never mix with bleach Delimer plus chlorine can form a hazardous gas Hobart's warning for chemical-sanitizing dish machines. In this guide 1. What scale does inside a steamer or combi oven 2. How often the makers ask for it 3. Why every model has its own procedure 4. Handling delimer safely 5. Step by step 6. Questions ## What scale does inside a steamer or combi oven Hard water carries dissolved calcium and magnesium that stay behind when it boils. Blodgett calls deliming the steam generator the single most important preventive maintenance task, because lime builds up inside it, cuts efficiency and damages the boiler. Cleveland notes that scale collects in the bottom of a SteamChef reservoir and in its drain, and that removing it can prevent a costly service call. Scale does its damage quietly. A coated element takes longer to make steam, a crusted level probe can tell the controller the tank is full or empty when it is not, and a narrowed drain leaves water standing in the cabinet. By the time the crew notices slow cooking, the scale has usually been there for weeks. Source: [Blodgett — BCX and BX combi oven manual](https://middleby-cdn.com/usermanuals/Blodgett_BCX-BX_CombiOven_Manual_1.pdf) — Deliming the steam generator is the single most important preventive maintenance task; problems from insufficient deliming are not covered by the warranty; reminder after 30 hours of boiler operation; interval settings by water hardness; cycle about 45 minutes after cooling below 140°F.; [Cleveland — SteamChef 22CET3.1 and 22CET6.1 operator's manual, archived copy](https://web.archive.org/web/20101122223545/http://clevelandrange.com/docs/uploaded/cle/CRManuals/22CET(ES)-OPM_Rev.C_MAY_07.pdf) — Scale deposits in the reservoir and drain; feed water under 60 ppm dissolved solids and 20 ppm alkalinity; poor feed water voids warranties; frequency set by the owner; use only DISSOLVE descaler; the 22CET procedure takes about 1 hour 30 minutes with the steamer unheated; gloves and eye protection required. ## How often the makers ask for it There is no single interval, because water differs from one street to the next. Each maker sets its own rule, and several let the unit decide. - Alto-Shaam CT PROformance combis: descale monthly, with the steam generator and oven interior on its monthly checklist. - Blodgett BCX combis: a delime reminder after 30 hours of boiler operation, with the interval set by local water hardness, from Setting A above 14 grains per gallon to Setting C below 7. - Rational iCombi Pro: the iCareSystem shows care status as green, yellow or red, and a red status calls for a cleaning program at the next prompt at the latest. - Cleveland SteamChef boilerless steamers: descaling is not normally required, and its frequency is set by the owner according to water quality and daily cleaning. ### Treat the water before blaming the schedule Frequent scale is usually a water problem. Cleveland sets SteamChef feed water at under 60 ppm dissolved solids and under 20 ppm alkalinity and states that poor feed water voids its warranties. Alto-Shaam leaves water quality and steam generator upkeep to the owner as well. Test the water, then size a filter or softener to the maker's figures. Source: [Blodgett — BCX and BX combi oven manual](https://middleby-cdn.com/usermanuals/Blodgett_BCX-BX_CombiOven_Manual_1.pdf) — Deliming the steam generator is the single most important preventive maintenance task; problems from insufficient deliming are not covered by the warranty; reminder after 30 hours of boiler operation; interval settings by water hardness; cycle about 45 minutes after cooling below 140°F.; [Cleveland — SteamChef 22CET3.1 and 22CET6.1 operator's manual, archived copy](https://web.archive.org/web/20101122223545/http://clevelandrange.com/docs/uploaded/cle/CRManuals/22CET(ES)-OPM_Rev.C_MAY_07.pdf) — Scale deposits in the reservoir and drain; feed water under 60 ppm dissolved solids and 20 ppm alkalinity; poor feed water voids warranties; frequency set by the owner; use only DISSOLVE descaler; the 22CET procedure takes about 1 hour 30 minutes with the steamer unheated; gloves and eye protection required.; [Alto-Shaam — Combitherm CT PROformance operator's manual (MN-35948), archived copy](https://web.archive.org/web/20220509173647/https://www.alto-shaam.com/en/media-library/widen-assets/technical-literature/operators-manual/operators-manual_combitherm_ctp_mn-35948-en-18-pdf.pdf) — Descale monthly with 7 ounces of Scale Free in the drain and a heavy-duty cleaning cycle; water quality and steam generator maintenance are the owner's responsibility; damage from cleaning agents not recommended by Alto-Shaam is excluded.; [Rational — iCombi Pro 20-1/1 and 20-2/1 original instructions for use (US)](https://hcms.rational-online.com/hcms/v1.7/entity/documents/155435/storage/MTU1NDM1LzAvbWFzdGVyLy8vMTAxNTcwMzIw/download/manual_original_instruction_icombi_pro_20-1_1,_20-2_1_english_usa.pdf) — iCareSystem shows care status green, yellow or red; only Rational cleaner and care tabs in automatic cleaning; the steam nozzle is removed and soaked in descaler; safety eyewear and chemical-resistant gloves. Close on white scale on the inside wall of a steamer compartment. ## Why every model has its own procedure Cleveland warns that descaling differs by model and that the whole procedure must be read before starting. The differences are large. Rational's iCombi Pro removes scale inside its automatic cleaning programs with Rational care tabs, and its manual has the steam nozzle unscrewed and soaked in descaler separately. Blodgett's BCX draws delimer from a jug through its own pump and runs the cycle itself in about 45 minutes once the cabinet is below 140°F. Alto-Shaam's CT PROformance takes 7 ounces of its Scale Free product in the drain and a heavy-duty cleaning cycle. Because of that, the steps below follow one model only, the Cleveland SteamChef 22CET boilerless steamer, as its operator's manual gives them. Use them as a picture of what the job involves, and follow your own manual on your own unit. ### Only the product the maker names Cleveland names DISSOLVE descaler and says no other product or method should be used. Rational allows only its own cleaner and care tabs in automatic cleaning, and Alto-Shaam excludes damage from cleaning agents it did not recommend. A generic acid from the chemical closet can pit stainless steel, attack seals and void coverage in one afternoon. ### Dish machines and booster heaters Dish machines scale too. Hobart recommends water at 3 grains of hardness per gallon or less, says to delime when a white chalky film shows on the walls and wash arms or when the machine prompts, and runs the delime from its menu with a 10-minute wash and a 1-minute flush. Source: [Blodgett — BCX and BX combi oven manual](https://middleby-cdn.com/usermanuals/Blodgett_BCX-BX_CombiOven_Manual_1.pdf) — Deliming the steam generator is the single most important preventive maintenance task; problems from insufficient deliming are not covered by the warranty; reminder after 30 hours of boiler operation; interval settings by water hardness; cycle about 45 minutes after cooling below 140°F.; [Cleveland — SteamChef 22CET3.1 and 22CET6.1 operator's manual, archived copy](https://web.archive.org/web/20101122223545/http://clevelandrange.com/docs/uploaded/cle/CRManuals/22CET(ES)-OPM_Rev.C_MAY_07.pdf) — Scale deposits in the reservoir and drain; feed water under 60 ppm dissolved solids and 20 ppm alkalinity; poor feed water voids warranties; frequency set by the owner; use only DISSOLVE descaler; the 22CET procedure takes about 1 hour 30 minutes with the steamer unheated; gloves and eye protection required.; [Alto-Shaam — Combitherm CT PROformance operator's manual (MN-35948), archived copy](https://web.archive.org/web/20220509173647/https://www.alto-shaam.com/en/media-library/widen-assets/technical-literature/operators-manual/operators-manual_combitherm_ctp_mn-35948-en-18-pdf.pdf) — Descale monthly with 7 ounces of Scale Free in the drain and a heavy-duty cleaning cycle; water quality and steam generator maintenance are the owner's responsibility; damage from cleaning agents not recommended by Alto-Shaam is excluded.; [Rational — iCombi Pro 20-1/1 and 20-2/1 original instructions for use (US)](https://hcms.rational-online.com/hcms/v1.7/entity/documents/155435/storage/MTU1NDM1LzAvbWFzdGVyLy8vMTAxNTcwMzIw/download/manual_original_instruction_icombi_pro_20-1_1,_20-2_1_english_usa.pdf) — iCareSystem shows care status green, yellow or red; only Rational cleaner and care tabs in automatic cleaning; the steam nozzle is removed and soaked in descaler; safety eyewear and chemical-resistant gloves. ## Handling delimer safely Descalers are acids. Cleveland calls for rubber gloves, OSHA-approved eye protection and protective clothing, and Rational asks for close-fitting safety eyewear and chemical-resistant gloves around its cleaning products. Hobart adds the warning that matters most in a kitchen with chemical-sanitizing machines: delimer must never meet bleach or a rinse containing bleach, because the mix can form a hazardous gas. - Gloves, goggles and sleeves on before a container is opened. - Delimer kept on its own shelf, away from chlorine sanitizer. - The cabinet cool and the unit off where the manual says so. - Nobody cooking in the unit until the final rinse is complete. Source: [Cleveland — SteamChef 22CET3.1 and 22CET6.1 operator's manual, archived copy](https://web.archive.org/web/20101122223545/http://clevelandrange.com/docs/uploaded/cle/CRManuals/22CET(ES)-OPM_Rev.C_MAY_07.pdf) — Scale deposits in the reservoir and drain; feed water under 60 ppm dissolved solids and 20 ppm alkalinity; poor feed water voids warranties; frequency set by the owner; use only DISSOLVE descaler; the 22CET procedure takes about 1 hour 30 minutes with the steamer unheated; gloves and eye protection required.; [Rational — iCombi Pro 20-1/1 and 20-2/1 original instructions for use (US)](https://hcms.rational-online.com/hcms/v1.7/entity/documents/155435/storage/MTU1NDM1LzAvbWFzdGVyLy8vMTAxNTcwMzIw/download/manual_original_instruction_icombi_pro_20-1_1,_20-2_1_english_usa.pdf) — iCareSystem shows care status green, yellow or red; only Rational cleaner and care tabs in automatic cleaning; the steam nozzle is removed and soaked in descaler; safety eyewear and chemical-resistant gloves.; [Hobart — LXn and LXGn series dish machine instructions (F41243)](https://www.hobartcorp.com/sites/default/files/webdam-assets/LXn%20Dishwashers%20Instructions%20Manual%20F41243%20(10-23).pdf) — Recommended hardness 3 grains per gallon or less; delime when lime deposits show or the machine prompts; 10-minute delime wash and 1-minute flush; deliming solution must not contact bleach, since mixing may form hazardous gas. ## Where to stop Book a visit when a unit still shows a water level or steam generator alarm after deliming, when scale returns within days, when water leaks from under the cabinet, or when a steam generator needs its elements or hand hole opened. Cleveland limits descaling to its own technicians or trained onsite maintenance staff, and anything behind a panel with power or gas connected stays with a technician. Written by [CommercialApplianceRepair.center technical team](https://commercialappliancerepair.center/authors/technical-team/). Technicians who service restaurant, institutional and laundry equipment, working from site visits, service logs and makers' manuals. Sources: [Blodgett — BCX and BX combi oven manual](https://middleby-cdn.com/usermanuals/Blodgett_BCX-BX_CombiOven_Manual_1.pdf) · [Cleveland — SteamChef 22CET3.1 and 22CET6.1 operator's manual, archived copy](https://web.archive.org/web/20101122223545/http://clevelandrange.com/docs/uploaded/cle/CRManuals/22CET(ES)-OPM_Rev.C_MAY_07.pdf) · [Alto-Shaam — Combitherm CT PROformance operator's manual (MN-35948), archived copy](https://web.archive.org/web/20220509173647/https://www.alto-shaam.com/en/media-library/widen-assets/technical-literature/operators-manual/operators-manual_combitherm_ctp_mn-35948-en-18-pdf.pdf) · [Rational — iCombi Pro 20-1/1 and 20-2/1 original instructions for use (US)](https://hcms.rational-online.com/hcms/v1.7/entity/documents/155435/storage/MTU1NDM1LzAvbWFzdGVyLy8vMTAxNTcwMzIw/download/manual_original_instruction_icombi_pro_20-1_1,_20-2_1_english_usa.pdf) · [Hobart — LXn and LXGn series dish machine instructions (F41243)](https://www.hobartcorp.com/sites/default/files/webdam-assets/LXn%20Dishwashers%20Instructions%20Manual%20F41243%20(10-23).pdf) ## Step by step. Five steps, in the order worth doing them. 01 ### Drain and clear the cabinet Open the door, set the timer or control to off so the 3-minute drain runs, remove the pan racks and KleanShield, and lift out any loose scale from the bottom. 02 ### Refill and add the descaler Turn the unit back on to refill without starting the timer, leave the door open, and pour in 1 to 1½ quarts of DISSOLVE slowly while it fills; do not heat the steamer. 03 ### Let it soak for an hour When the fill ends, switch off the main external power switch and leave the descaler in the reservoir, door open, for 1 hour. 04 ### Drain, refill and heat to rinse Restore power, drain, refill and add half a gallon of water, drain again, refill, then close the door and heat for 20 minutes before a final drain. 05 ### Check the drain and return to service If the reservoir still drains slowly, clean the drain with an NSF-approved drain cleaner; once it flows freely the steamer is ready for normal use. For the heart of your home. ## Questions owners ask. ### Is vinegar enough to keep scale away? It helps with daily wiping. Cleveland suggests a half vinegar, half water wipe of the SteamChef cabinet each day to slow scale, but the reservoir itself is descaled with the maker's product. ### Can we skip deliming if we installed a water softener? Not entirely. Treatment slows scale, and some makers let you lengthen the interval with filtered water, but the unit's own reminder or care status still decides when it is due. ### Why does our combi ask for deliming more often than the one at our other location? Usually the water. Hardness varies between neighborhoods, and a combi that steams all day builds scale faster than one used mostly in dry heat. ## The problems behind it. Each has a page of its own: what it usually means and the causes in the order worth checking. [All 17 problems](https://commercialappliancerepair.center/problems/) Problem ### Combi Oven Steam Problem: Weak Steam, Scale or a Dry Cavity 6 causes, cheapest first Problem ### Dish Machine Not Reaching Temperature on the Wash or Final Rinse 6 causes, cheapest first Problem ### Commercial Appliance Error Code on a Combi, Fryer, Dish Machine or Laundry Display 8 causes, cheapest first ## When it needs a technician. The repairs on the right are where this guide ends when the checks do not settle it. ### Commercial oven and combi oven repair Convection, combi and rapid-cook ovens, steamers and kettles: blowers, steam generators, probes, igniters and controllers. ### Dish machine repair Undercounter, door-type and conveyor dish machines: tank heaters, boosters, wash pumps, fill and drain valves. ### Commercial preventive maintenance plan Scheduled visits across cold, cooking, warewashing and laundry: coils, gaskets, calibration, gas checks and a written log. ## More in maintenance and prevention. The routines that keep commercial equipment off our schedule, from cleaning condenser coils and filtering fryer oil to deliming combis and boosters, checking gaskets and emptying lint screens. [The whole section](https://commercialappliancerepair.center/guides/maintenance-and-prevention/) A maintenance plan that keeps the line running ### A Preventive Maintenance Plan That Pays: Daily, Monthly and Yearly Tasks From the Manuals Why the plan belongs on paper, a schedule built from the makers' own intervals for fryers, combis, cold cabinets, dish machines and tumblers, who does which task, and logs that show where the next repair is coming from. A maintenance plan that keeps the line running ### Cleaning Condenser Coils on a Schedule: Reach-In Intervals, Grille Access and Greasy Fins Why a matted coil shortens compressor life, the intervals Delfield, Turbo Air and Traulsen publish, where the coil sits on each cabinet, the power-off steps from the manuals, and when a greasy coil goes to a technician. Guides ### All 18 guides Six sections, by what you are trying to find out. --- **[Read on the site: Deliming Steamers and Combi Ovens: Hard Water, Maker Intervals and a Descaling Cycle Step by Step](https://commercialappliancerepair.center/guides/deliming-steamers-and-combi-ovens/)** **[Book a visit with CommercialApplianceRepair.center](https://commercialappliancerepair.center/schedule/)**