(a) General rules.
(1) Air conditioning and refrigeration.
(i) Each direct water connection to a refrigeration or air conditioning unit using City water for cooling purposes shall be equipped with a check valve set not more than two (2) feet from the unit.
(ii) Each unit containing more than twenty (20) pounds of refrigerant shall be provided with a relief valve installed between the check valve and the unit. The relief valve shall be set at five (5) pounds above the maximum water pressure at the point of installation.
(iii) All water-cooled air conditioning or refrigeration systems shall be connected to a metered supply.
(iv) Water conserving devices shall be designed and operated in accordance with American Society for Heating, Refrigeration and Air Conditioning (ASHRAE) standards that consumes City water for make-up purposes at no more than two (2) percent of the total flow of water through the system. An additional two (2) percent shall be allowed for the purpose of bleeding and wash down.
(v) Where the City water is piped to a water conserving device, the piping supplying such water shall discharge at least two (2) inches above the over-flow rim of the pan.
(vi) Condensate from steam used directly or indirectly to produce the cooling effect in air conditioning or refrigeration systems shall be collected and used as part of the make-up water to the water conserving device or shall be put to some other beneficial use which displaces potable water.
(2) Refrigeration.
(i) All refrigeration systems in excess of six (6) tons of rated capacity using City water and installed before January 1, 2011 must be equipped with approved water conserving devices. Once-through, water-cooled refrigeration systems are prohibited in new construction effective January 1, 2011, in accordance with § 428.1.1 of the New York City Plumbing Code.
(ii) All refrigeration systems of six (6) tons of rated capacity or less using City water without an approved water conserving device shall be equipped with an automatic water regulating device on each individual unit.
(3) Air Conditioning.
(i) All air conditioning systems in excess of two (2) tons of rated capacity using City water and installed before January 1, 2011 must be equipped with an approved water conserving device. Once-through, water-cooled air conditioning equipment is prohibited in new construction effective January 1, 2011, in accordance with § 428.1.1 of the New York City Plumbing Code.
(ii) All air conditioning systems of two (2) tons of rated capacity or less using City water without an approved water conserving device shall be equipped with an automatic water regulating device on each individual unit.
(b) Hours of use of air conditioning systems.
(1) Hours of use of air conditioning systems may be limited by the Department from time to time as water supply conditions so warrant.
(2) Lists of "permissible hourly operation" will be on file in the Department and may be obtained upon request.
(3) The hours during which air conditioning using City water is allowed shall be posted prominently in each building and establishment using such air conditioning.
(c) Variances. The Department will receive and review requests for variances from this section due to demonstrated peculiar individual situations.