This is the fourth edition of CSA C191, Performance of electric storage tank water heaters for domestic hot water service. It supersedes the previous edition, published in 2000 under the title Performance of Electric Storage Tank Water Heaters for Household Service. The 2000 edition superseded the previous editions of the CAN/CSA-C191 Series, which consisted of CAN/CSA-C191.0, Performance and Energy Efficiency of Electric Storage Tank Water Heaters, and CAN/CSA-C191.1, Performance Options for Electric Storage Tank Water Heaters. Those editions of CAN/CSA-C191 Series were published in 1990 and 1983.
This Standard specifies requirements related to delivery, minimum standby performance, heater element ratings, and marking of electric storage tank water heaters.
This Standard applies to stationary storage tank water heaters that have a rated capacity of 184 or 284 L (40 or 60 gal) and are intended for use with pressure systems in residential premises and similar locations.
For convenience, the term water heater is used in this Standard to refer to such heaters. In addition, the standby loss test and its associated calculation (see Clause 4.8) may be applied to stationary storage tank water heaters that have a rated capacity of 50 to 454 L (11 to 100 gal).
In CSA Standards, shall is used to express a requirement, i.e., a provision that the user is obliged to satisfy in order to comply with the standard; should is used to express a recommendation or that which is advised but not required; and may is used to express an option or that which is permissible within the limits of the standard. Notes accompanying clauses do not include requirements or alternative requirements; the purpose of a note accompanying a clause is to separate from the text explanatory or informative material.
Notes to tables and figures are considered part of the table or figure and may be written as requirements. Legends to equations and figures are considered requirements.
Units of measurement
The values given in SI (metric) units are the standard. The values given in parentheses are for information only. All measurements in gallons refer to imperial gallons.