diff --git a/lib/cartodb/backends/cluster.js b/lib/cartodb/backends/cluster.js
index e305eb28..f858b27a 100644
--- a/lib/cartodb/backends/cluster.js
+++ b/lib/cartodb/backends/cluster.js
@@ -7,7 +7,7 @@ const AggregationMapConfig = require('../models/aggregation/aggregation-mapconfi
 
 module.exports = class ClusterBackend {
     // TODO: reduce complexity
-    // jshint maxcomplexity: 13
+    // jshint maxcomplexity: 10
     getClusterFeatures (mapConfigProvider, params, callback) {
         mapConfigProvider.getMapConfig((err, _mapConfig) => {
             if (err) {
@@ -43,7 +43,7 @@ module.exports = class ClusterBackend {
 
             let { aggregation } = params;
 
-            if ( aggregation !== undefined) {
+            if (aggregation !== undefined) {
                 try {
                     aggregation = JSON.parse(aggregation);
                 } catch (err) {
@@ -77,10 +77,9 @@ module.exports = class ClusterBackend {
                 }
 
                 if (expressions !== undefined) {
-                    if (!isValidExpression(expressions)) {
-                        const error = new Error(
-                            `Invalid aggregation input, expressions should be and object with valid functions`
-                        );
+                    try {
+                        validateExpressions(expressions);
+                    } catch (error) {
                         error.http_status = 400;
                         error.type = 'layer';
                         error.subtype = 'aggregation';
@@ -91,36 +90,6 @@ module.exports = class ClusterBackend {
 
                         return callback(error);
                     }
-
-                    for (const { aggregate_function, aggregated_column } of Object.values(expressions)) {
-                        if (typeof aggregated_column !== 'string') {
-                            const error = new Error(`Invalid aggregation input, aggregated column should be an string`);
-                            error.http_status = 400;
-                            error.type = 'layer';
-                            error.subtype = 'aggregation';
-                            error.layer = {
-                                index: layerIndex,
-                                type: layer.type
-                            };
-
-                            return callback(error);
-                        }
-
-                        if (typeof aggregate_function !== 'string') {
-                            const error = new Error(
-                                `Invalid aggregation input, aggregate function should be an string`
-                            );
-                            error.http_status = 400;
-                            error.type = 'layer';
-                            error.subtype = 'aggregation';
-                            error.layer = {
-                                index: layerIndex,
-                                type: layer.type
-                            };
-
-                            return callback(error);
-                        }
-                    }
                 }
             }
 
@@ -264,6 +233,22 @@ function hasColumns (columns) {
     return Array.isArray(columns) && columns.length;
 }
 
+function validateExpressions (expressions) {
+    if (!isValidExpression(expressions)) {
+        throw new Error(`Invalid aggregation input, expressions should be and object with valid functions`);
+    }
+
+    for (const { aggregate_function, aggregated_column } of Object.values(expressions)) {
+        if (typeof aggregated_column !== 'string') {
+            throw new Error(`Invalid aggregation input, aggregated column should be an string`);
+        }
+
+        if (typeof aggregate_function !== 'string') {
+            throw new Error(`Invalid aggregation input, aggregate function should be an string`);
+        }
+    }
+}
+
 function isValidExpression (expressions) {
     const invalidTypes = ['string', 'number', 'boolean'];