TECH REPORT: Taking Care of Steamers & Combis

If you’ve ever had a steamer or combi in your kitchen, you know they’re two of the more maintenance-sensitive pieces of equipment in your arsenal. That said, it’s worth noting that doing the maintenance actually is pretty straightforward and simple. All you have to do is follow the directions and devote a few minutes each day. Do that, and you’ll see the payback in vastly better performance and fewer service calls. Ignore a few basic items, though, and you proceed at your own risk.

It’s The Water

Whether you’re talking about a boiler/generator-driven unit, a boilerless model with plumbing, or a connectionless model, the first key to maintenance is the water quality. Get it right, and you’ll spend less time compensating for bad water. Get it wrong, and you’re in for a long uphill run. Unfiltered tap water is never a good idea, regardless of connections and generators, or lack thereof.

“All water is local,” as one manufacturer we interviewed for this story put it. And when he says “local,” he means right there on site. In some areas, you could test the water at locations a block apart and get results different enough to require different kinds of filters. Which means the standard water reports from the local water company won’t be specific enough about your street address.

So call your local service rep, manufacturer’s rep or dealer and find out who in your area will come out to get a water sample and test it. Or find out where you can get a test kit and do it yourself. Once you know what kinds of minerals, other solids and contaminants you might have, in what levels, you’ll know what kinds of filtration to look for.

For steamers and combis, the two biggest concerns in water are mineral deposits and disinfectant agents. Among mineral deposits, lime is the usual suspect, but it’s not the only one. If your water supply isn’t filtered, minerals float in with the water and build up along the flow route over time. That sediment accumulates especially quickly wherever the water is being heated and turning to steam. Sediment can cause blockages, hindering the passage of water at inlets, drains and in between, as well hindering the transfer of heat from burners or elements to the water.

As for disinfectants, historically the most common one is chlorine. Chlorine is notoriously corrosive to metals, including stainless steel and iron, and that’s why it needs to be taken out of water going to cooking equipment. Also worth noting, temperature makes a difference. And adding heat makes chlorine more corrosive.

Chloramines On The Rise

Cousins of chlorine, chloramines are even more damaging to steel, stainless, copper and other metals. Chloramines are combinations of chlorine and ammonia, and they’ve been used in some water supplies as disinfectants for decades. They’re usually used in combination with chlorine, and they have advantages and disadvantages. On the negative side, they’re not as effective as chlorine for disinfecting. But on the flip side, they’re much more stabile and longer lasting in the water, and chloramines don’t impart the odors and tastes associated with chlorine. Plus chlorine has some negative health and air-quality implications, and chloramines offer a viable alternative.

What’s news about all this is that chloramines are showing up in more and more water supplies, and operators who might be a little loose with routine maintenance are seeing much accelerated corrosion and not knowing why.

All that is to say this: You really want a filtration system. And before we leave the topic of filtration, here’s one more note: Filter maintenance is just as important as anything else in your kitchen. As filters do their jobs, they fill up, and water flow is hindered. Which means the water coming into your steamer or combi is coming in at a lower pressure. If you’re using any kind of steam generator that creates its own positive pressure, your incoming water flow could be even further slowed. So watch your filter, learn to read the pressure gauge if you have one and change filters in a timely fashion.

Installation & Factory Recommendations

So once you’ve dealt with your incoming water supply, the steamer or combi comes next. And this part might sound like a broken record, but you really need to read the manufacturer’s materials, follow the recommended maintenance schedule, etc. There is no shortcut worth taking, and that’s especially true with equipment that uses water. “Manufacturers’ periodic cleaning instructions are paramount,” one manufacturer said. Do the simple periodic tasks, and you’ll prevent big failures and expenses down the road.

Staying on schedule is extremely important, all manufacturers will tell you, and the heavier your usage, the more important the schedule. Obviously, a steamer or combi at a school is one thing; one at a 24-hour casino is something else entirely. One manufacturer said he recommends operators schedule periodic tasks, such as changing filters, on Microsoft Outlook Calendar. It’s handy, right there on the operator’s computer and “one of the nice things is you can reset the pop-up notice.”

As several makers emphasize, the recommendations start with the installation. Make sure you get someone qualified to do the installation and start-up properly, accounting for proper water pressure, electric rating or gas pressure, elements or burners, water inlet and drain fittings, etc.

And give careful thought to where you’re locating your steam equipment. One manufacturer tells of an investigation of a field problem that revealed scorch marks on an external side panel, suggesting a high heat source butting up against the steamer. So observe clearance requirements, and use your head about nearby sources of heat and/or airborne grease. Neither is good for controls, air intakes, etc.

Boiler & Generator Steamers

Does your equipment have a boiler or generator? Most do. Often the terms are used interchangeably, but when they’re not, boiler often but not always refers to a steam generator that creates some positive pressure, while generator

  • Daily compartment maintenance is minimal beyond the basic cleaning/wiping down with vinegar or factory-recommended cleaner.
  • Periodically descale the generator based on usage, water quality and factory recommendations. Generally, descale countertop units quarterly and boiler style steamers twice a year based on usage. Descaling also will clean out the lines and keep the drain free and clear.

Boilerless, Plumbed Steamers

Regardless of whether or not your unit has a boiler/generator, if it has a connection for incoming water or for the drain:

  • The drain is active during cooking and most proteins and starches are flushed, which means the compartment might only need a weekly cleaning, depending on usage and menu. Other than that, it should just need a daily wipe down, as with any steamer.
  • De-lime according to the manufacturer’s schedule.

Connectionless Steamers

One of the great things about connectionless steamers is that they’re simpler. No generator, no plumbing. Just an open vessel, manually filled with water, heated by gas or electric elements. They use much less water—roughly a tenth as much—than a conventional, plumbed unit, and much of that water savings is because they don’t require a condensate drain. With no drain, they don’t need to run extra water down the drain to cool the temperature of the condensed steam.

Ironically, however, that simplicity can lull operators into skipping maintenance completely, and that’s a mistake.

Start with filtered water, which seems like an obvious idea. But in the heat of kitchen battle, staffers usually go to the closest water source to refill. And if the closest source isn’t filtered, you’re pouring a problem into your equipment.

  • Without a drain, the unit needs more frequent cleaning. Clean the vessel and the compartment daily, wiping down with vinegar or according to manufacturer’s recommendation.
  • If your steamer has elements immersed in the water, the sediment insulates the elements, slowing heat transfer and causing premature failure. Deliming is crucial. Remove the reservoir, add the deliming/cleaning solution according to manufacturer’s instructions, soak and flush.


In general, what applies to steamers applies to combis, too. If you’re buying a new unit, consider an auto clean option for the interior as well as for the boiler/generator system if available. Cleaning the compartment will be especially important if you use the unit for roasting. One of the manufacturers notes the type of water filter is important—Scalestick types, he says, may cause abrasion on the compartment walls and the windows.

A Word On Door Gaskets

A good seal on a steam compartment obviously is important, so door gaskets are important. They need to be pliable to create a good seal, so they need to “breathe” when the steamer or combi is not in use. To do that, keep doors open when possible. That’ll extend the gasket life and also air out the compartment.

Do the basics, and you should be able to extend the life of your equipment and reduce service calls significantly.


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