
    Merchants Mutual Insurance Company, as Subrogee of Sox Box of Forest Hills, Inc., Respondent, v Surrey Electric Company, Inc., Appellant. (And Other Actions.)
   In a subrogation action to recover the sum paid by the plaintiff insurer to its insured as a result of a fire on the insured premises on the ground that the defendant’s negligence allegedly caused the fire, the defendant Surrey Electric Company, Inc., appeals from an order of the Supreme Court, Queens County (Sacks, J.), dated July 24, 1986, which granted the plaintiffs motion for summary judgment and set the matter down for an assessment of damages.

Ordered that the order is reversed, on the law, with costs, and the plaintiffs motion is denied.

On January 9, 1984, the defendant installed an electric heating system consisting of a ceiling-suspended unit heater, and a wall-mounted line voltage thermostat in the insured premises, a women’s apparel store. On the evening of December 24, 1984, a fire broke out in the store. In the opinion of the plaintiffs expert, the defendant’s misuse of a low-current-rated line voltage thermostat was the proximate cause of the fire. The defendant’s expert, on the other hand, concluded, upon an examination of the thermostat involved in the fire, that the thermostat had not caused the fire. Rather, the expert determined that the thermostat had been damaged by the fire.

Inasmuch as the obligation of the court on a motion for summary judgment is issue finding rather than issue determination (see, Sillman v Twentieth Century-Fox Film Corp., 3 NY2d 395, 404, rearg denied 3 NY2d 941), we conclude that the Supreme Court erred in determining the cause of the fire and thereupon granting the plaintiffs motion. In view of the-existence of disputed issues of fact, the case must proceed to trial. Weinstein, J. P., Eiber, Spatt and Sullivan, JJ., concur.  