In cooperation with CSA International, Vulcano Termodomesticos SA of Averriro, Portugal, announced today a voluntary corrective action program for approximately 96 of their Aquastar and Bosch instantaneous natural gas water heaters.

The manufacturer has become aware that in many cases these water heaters have been installed for space heating purposes only, and that some installations may be using inadequately sized circulating pumps. The pump must provide sufficient pressure to ensure that the gas valve on the water heater opens properly. Incorrect pump sizing may lead to a blockage of the water heater and eventually to the release of carbon monoxide into the residence. CSA certification of these water heaters for space heating requires that they be used in combination with potable water heating.

Two incidents involving these water heaters have been reported in Canada. It is reported that one of these incidents resulted in two deaths from carbon monoxide poisoning.

Also, water heaters providing space or water heating may have been manufactured with a gas input higher than the certified rating. As a result, the heaters may be producing carbon monoxide in excess of acceptable levels. In the event of improper venting or negative pressures in the building in which the heaters were installed, there is the possibility of carbon monoxide entering the residence.

The water heaters affected by this corrective action program are “Aquastar” models AQ38-BNG and “Bosch” models W125KV3P23S(3100 or 3104) with or without suffix T1. The water heaters are white in color and are approximately 28 centimetres wide, 66 centimetres high and 23 centimetres deep and are intended for mounting directly on a wall. This program affects only units operating on natural gas and does not apply to units using propane gas.

The 96 units sold in Canada since January 1998 were distributed across the country. Approximately 300 units were sold in the U.S.

A program has been initiated by Vulcano to modify the water heaters to readjust the gas input. Consumers should stop using the affected water heaters immediately and call the Bosch representative, Astravan Distributors Ltd. at 1-800-663-8405 or the Aquastar representative, Controlled Energy Corporation at 1-800-642-3111 for further information on the corrective action program. The gas input correction will be made at no cost to the owner of the water heater. At the same time, any space heating installation will be evaluated to help ensure that it is correct