Cabinet Convectors

Frequently Asked Questions

Features and options:

Can I get an enclosure height or length not listed in the catalog? If so, how do I order them?

Yes, you can get custom height convectors, as this is something that Zehnder Rittling can easily accommodate. Simply select the next larger standard size for pricing and note the request in the comments of the order.

For example if you require a 30” high unit select the 32” height. The same applies for custom lengths. This is limited to 1” increments.

There may be an added price for this change. Custom lead times will apply.

What if the required size exceeds what is available in Rittling Online? What if they are smaller than available selections?

If you require a height greater than 32” or a length greater than 64” Zehnder Rittling may be able to provide a custom unit. There are limits to height and lengths based on unit style, material size, handling and assembly

If you require a height less than 18” or a length less than 24” Zehnder Rittling may be able to provide a custom unit. There are limits to shorter heights and lengths based on unit style, coil size/active area, position of the coil and inlets/outlets.

Convector sizes outside of the published dimensions must be reviewed and quoted by Zehnder Rittling.

There will be a price add for these changes. Custom lead times will apply.

What if a custom depth is required?

Custom depth convectors are not available due to depth and position of the coils used in the units. The only exception to this is 10” units. We are able to expand the depth to 10”, but not any incremental sizes.

There will be a price add for this change. Custom lead times will apply.

Why aren’t all access door locations available with all units?

Access door locations are limited based on the effect of the access doors on the inlet and outlet openings. In some combinations the location of the access doors would require the removal of significant inlet or outlet area. This in combination with the style height and length affects the available locations. See the catalog or submittal drawings for available arrangements.

Access door sizes are limited based on the unit size. For units that are 20” of less in height the standard size is 4” x 5”. For units over 20” the size is 5” x 5”.

Why are some options not available on some sizes?

There are certain options that cannot be used in conjunction with each other. We have logic built into the configurator that will not allow you to select them together, but that does not tell you why they are unavailable. For the most part it come down to space and/or interferences.

For example when ordering a 4” deep slope top unit, SL or SF style, you cannot use the bar grille outlet, as there is not enough room in the slope top to accommodate the grille. You also cannot have a damper on any bar grille unit.

If there is a question on any eliminated answer please contact the factory for clarification, if necessary.

What direction is the coil feed?

All coils have opposite end header connections. There are two choices for coil arrangements, same direction and opposite (one up feed and one down feed). The standard coil has the headers pointing in the same direction. This coil can be used as up or down feed for both the supply and return. The coil slides out of the side mounting brackets for the unit installation and can be piped in either arrangement.

The optional coil with up/down feed can be piped installed with either the supply or return in the up or down feed position.

See the catalog for additional piping information.

What if I only need to replace part of the unit?

There are many times that only the coil or the cabinet may need to be replaced, due to specific damage.

Replacing the coil can be done simply by determining the depth and overall length of the existing coil. Once you have that information you can contact customer service for a quote. Only the overall coil dimensions can typically be matched. See the submittal drawing for details.

Replacing the cabinet (unit without a coil) is also a custom option, though less common. The most common request for replacement is the front panel. Zehnder Rittling can match existing front panel sizes, however it is not always possible to match mounting styles. Typically replacement fronts are provided with mounting locations for fasteners only.

Price and lead time add, must be quoted by Zehnder Rittling prior to ordering. Custom lead times apply.

What color is your prime coat?

Our prime coat is unique to Zehnder Rittling, as we offer a powder coat finish as our prime coating. We collect the overspray powder that is part of the powder coating process and reuse that as a mixture for our prime coat. The color is different at any given time and cannot be matched. However it does provide a more durable finish than a typical prime, with no additional steps for field painting.

What do I need to do for field painting?

With the Prime coating the process is the same as any other field painting procedure. The surface should be scuffed/roughed up to ensure adhesion of the liquid paint. A oil based enamel paint (alkyd, acrylic, urethane, epoxy) should be used. Latex or lacquer paints should not be used. Spray the paint to achieve an even coating and let dry completely before using the product.

Any powder coating finish can be field painted, if desired by the customer. The process is the same for the standard colors as with the prime coating.

What about custom material or color?

Convectors are typically made from cold rolled steel and finish in one of our six standard powder coat finishes, or the standard Zehnder Rittling prime coat. However we can make them from alternate materials or custom color:

Stainless Steel

  • Unpainted, 304-4B finish is typical, though alternate finishes are available (polish/mirror finish not recommended).
  • 18 or 16ga available with any inlet or outlet, 14ga only available as perforated, 12ga is not available in stainless steel.
  • Price and lead time add, comments added to the order denoting what items are to be stainless. Customer service will make the necessary adjustments to the order.
  • Custom lead times apply.
  • Both fronts and liners must be stainless. With most models the sides of the unit are visible when the unit is installed. There is also contact between the two and any rusting or corrosion of a painted cold rolled steel liner can shorten the life of the stainless steel front.

Galvanized Steel

  • Unpainted for field finish. 18, 16, 14 gauge available
  • Price and lead time add, must be quoted by Zehnder Rittling prior to ordering.
  • Custom lead times apply.

Custom color

  • Zehnder Rittling is able to match existing or special colors. Color chip must be provided for match (manufactures part number alone is not recommended due to potential variations in charts/chips). Chips are typically not returned and may be cut for match by the vendor. Finished goods should not be sent for paint match.
  • Price and lead time match, see Custom pricing sheet. Price is dependent on total amount of units at time of order.
  • Orders can be placed for standard product with custom color selections by choosing the required product and adding a comment to the order referencing the color. Customer service will make the necessary adjustments to the order.
  • Chips should be sent to Zehnder Rittling customer service immediately to reduce lead time/delays.
  • Two processes are available for custom color orders, depending on required approval, that will affect lead time. If the chip is provided for match only the order can be entered and released once the chip is received by Zehnder Rittling.
  • If color match approval is required once the chip is provided it will be sent to our vendor for match. Chips will then be sent out to you for approval. Once the color is approved the order can be released for production.
  • Metallic matches are not available. However we are able to provide two metallic colors, Silversmith and Bright Argent. These are the only two approved metallic colors.
  • Contact customer service for samples.


Performance ratings:

How do I get performance data for my convectors?

It is recommended that you use for all performance rating and product capacity, including all cabinet unit heaters.

Base performance data can be found in the catalogs.