As an integral part of our continuous improvement process, you will begin to notice an update to our model number system for residential water heaters beginning in June 2006.  This change is essentially transparent since the base model number remains the same, but it is an important enhancement to our internal systems. 

This Product Bulletin explains the new model number system and has a sample rating plate and sample carton label detailing the improvements.

RESIDENTIAL GAS WATER HEATERS

For the residential gas water heaters, the engineering revision level will be removed from the base model number.  For example, an atmospherically vented 40 gallon unit currently has a model number of M-I-403S6FBN7.  The new model number will now be M-I-403S6FBN.  The engineering revision level will be in a separate field and will now be an alphanumeric value, starting with “A.”  This field will be to the right of the model number on the rating plate and under the bar code on the carton label (see Figures 1 and 4).  The engineering revision level may be important for future servicing or parts requirements.

If there is a need for a non-standard heater, a dash number will be added to the model number. For example, if the 40 gallon water heater is ordered with an aluminum anode, the new model number will be M-I-403S6FBN-264.  The dash number will be after the  “D/N:” on the rating plate, in the serial number line.  The carton label will have the dash number as part of the model number.  In addition, the carton label will have an explanation of the dash number, which in this case is Aluminum Anode.  Multiple dash numbers may be used.

RESIDENTIAL ELECTRIC WATER HEATERS

For the residential electric water heaters, the engineering revision level will also be removed from the base model number.  The configuration of the heater and element will be added as a suffix to the base model number.  Specifically, the element’s wattage and voltage will be called out as an extension of the model number.  In addition, the phase and wiring configuration will be denoted (see Figure 2).

For example, a 50 gallon M2 heater wired non-simultaneous single phase with 240 volt, 4500 watt upper element and 4500 watt lower element would have the suffix “-1NCWW”.   Therefore, the complete model number of the heater would be M250S6DS-1NCWW.  The details of the configuration can be found in Table 1.

As with the gas units, if there is a need for a non-standard heater, a dash number will be added to the model number.  For example, the model number for a 50 gallon M2 heater with an aluminum anode would be: M250S6DS-1NCWW-264.  The dash number will be after the  “D/N:” on the rating plate in the serial number line.  The carton label will have the dash number as part of the model number.  The carton label will also have an explanation of the dash number, which in this case is Aluminum Anode.  The heater’s electrical phase will also be added to both the rating plate and carton label (see Figures 3 and 4).

In an effort to simplify inventory and reduce potential code issues, most of our 240 volt elements will become dual rated -- meaning that the elements will generate a specific heat output (example: 4500 watts) at 240 volts and a “derated” output (example: 3500 watts) at 208 volts.  This, as well as the other electrical characteristics is captured in Tables 1 and Table 2.

Table 1.  Configuration (example:  -1NCWW)

*Note: “L” will be used ONLY for those models ordered as 208v and wattages of 5000, 5500 and 6000

Table 2.  Dual Rated Elements‡

‡ Note: These elements are dual rated only. Other elements that are non dual rated are available.

Most standard 240 volt products use dual rated elements.  When a 208 volt model is ordered, the wattage designator in the model number will be based on the higher voltage (240 volt) if it has the dual rated element.  For example, if a 208V/4500 watt model were ordered, the last two characters would be ZZ (6000W /6000W at 240V, but 4500W / 4500W at 208V).

Therefore, the model number for the 50 gallon M2 electric heater with a single phase, non-simultaneous, 208 volt, 4500W/4500W configuration would now be: M250S6DS-1NCZZ.

For non-simultaneous wiring, the rating plate (Figure 3) will show the maximum wattage as the wattage of the element with the highest wattage.  For simultaneous wiring, the rating plate will show the maximum wattage as the sum total wattage of both elements.

As noted in Table 1, for residential electric water heaters that need 5000 watts or greater on 208 volt service, the voltage designator has to be an “L”.  So, going back to our example heater, if we wanted to use 5000 watts in a 50 gallon M2 heater, the model number would then be M250S6DS-1NLXX.

OLD/EXISTING MODEL NUMBERS

To aid in the transition, the previous model number will be printed under the new model number information on the carton label.  Please see the note “Prior Model” on Figure 4.

A model number converter has been developed and will be available on our website to aid in model number translation.  This can be accessed here.  Towards the top of the page will be a Search box.  Entering the current (legacy) model number will return the corresponding new model number.  Entering the new model number will return the legacy model number.  A brief description of the heater is also included.

In summary, the “new” model numbers do not reflect a major change, but rather an extension of the base model number.  However, if it is needed, we can provide a spreadsheet that shows a customer’s purchase history by current model number, current UPC, and the corresponding new model number and new UPC.

PB 052606