diff --git a/pina/solvers/pinns/rbapinn.py b/pina/solvers/pinns/rbapinn.py
index 770b0a7..527f2f4 100644
--- a/pina/solvers/pinns/rbapinn.py
+++ b/pina/solvers/pinns/rbapinn.py
@@ -117,7 +117,7 @@ class RBAPINN(PINN):
         # initialize weights
         self.weights = {}
         for condition_name in problem.conditions:
-            self.weights[condition_name] = 0
+            self.weights[condition_name] = 1
 
         # define vectorial loss
         self._vectorial_loss = deepcopy(loss)
@@ -158,7 +158,7 @@ class RBAPINN(PINN):
         residual = self.compute_residual(samples=samples, equation=equation)
         cond = self.current_condition_name
 
-        r_norm = self.eta * torch.abs(residual) / torch.max(torch.abs(residual))
+        r_norm = self.eta * torch.abs(residual) / (torch.max(torch.abs(residual))+1e-12)
         self.weights[cond] = (self.gamma * self.weights[cond] + r_norm).detach()
 
         loss_value = self._vectorial_loss(