Melvin purchased a heavy duty water heater manufactured by Heatco to use as a backup to his solar water heater. The solar heater only worked on sunny days, so Melvin wanted to link the water heater and the solar heater so that the water heater tank would hold solar-heated water when available but activate to provide gas-heated water on overcast days. Melvin asked his neighbor Paul to assist him with the installation of the water heater. When the installation was complete, Melvin and Paul got a couple of beers and a couple of chairs and sat down in front of the heater to see how their efforts succeeded. Melvin opened the valve, which permitted water to enter the tank from the solar unit. Because of a defective pressure relief valve in the water heater, the valve failed to activate until the water from the solar unit entering the water heater became superheated. The link then suddenly exploded, seriously scalding Melvin and Paul. Paul brought an action against Heatco for the physical injuries he suffered as a result of the water heater explosion. Which party will probably win this lawsuit