
374 So.2d 553 (1979)
Nolan BREWER, Thomas Duckett and Ronald Shears, Petitioners,
v.
William J. VANDERVALK et al., Respondents.
No. 79-798.
District Court of Appeal of Florida, Third District.
July 31, 1979.
Rehearing Denied August 29, 1979.
Leo Greenfield, North Miami, for petitioners.
John R. Sutton, Coral Gables, for respondents.
Before PEARSON, HENDRY and SCHWARTZ, JJ.
PER CURIAM.
We are presented with a petition for writ of certiorari to review a judgment of the circuit court acting in its appellate capacity. See Fla.R.App.P. 9.030(b)(2)(B). The question for our determination is whether the circuit court's affirmance of a county court's judgment amounted to a departure from established principles of law. See Sossin Systems, Inc. v. City of Miami Beach, 262 So.2d 28 (Fla. 3d DCA 1972). We will not pass upon the merits of the appeal taken to the circuit court. See Brinson v. Tharin, 99 Fla. 696, 127 So. 313, 316 (1930); and State v. Katz, 108 So.2d 60 (Fla. 3d DCA 1959).
The petitioners urge that the circuit court should have found that the respondents were estopped to maintain their action for possession in the trial court because of an agreed renewal of the lease to the disputed premises. The existence of estoppel in pais is a question to be determined by the trier of fact. See 28 Am.Jur.2d Estoppel and Waiver § 149 (1966), and cases cited thereat. The trial court upon disputed facts failed to find an estoppel. The circuit court in its appellate capacity found no error. We will not substitute our judgment for that of the two courts concerned.
Certiorari denied.
