diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/common/IValidable.java b/navalplanner-business/src/main/java/org/navalplanner/business/common/IValidable.java
new file mode 100644
index 000000000..155645bff
--- /dev/null
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/common/IValidable.java
@@ -0,0 +1,21 @@
+package org.navalplanner.business.common;
+
+import org.navalplanner.business.common.exceptions.ValidationException;
+
+/**
+ * Entities implementing this interface have a method <code>checkValid</code>.
+ * This method validates the business rules of the entity.
+ *
+ * @author Manuel Rego Casasnovas <mrego@igalia.com>
+ */
+public interface IValidable {
+
+    /**
+     * Checks if an entity is or not valid.
+     *
+     * @throws ValidationException
+     *             if entity is not valid.
+     */
+    void checkValid() throws ValidationException;
+
+}
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/orders/daos/IOrderDAO.java b/navalplanner-business/src/main/java/org/navalplanner/business/orders/daos/IOrderDAO.java
index b6b5209db..8b277bd45 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/orders/daos/IOrderDAO.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/orders/daos/IOrderDAO.java
@@ -1,5 +1,7 @@
 package org.navalplanner.business.orders.daos;
 
+import java.util.List;
+
 import org.navalplanner.business.common.daos.IGenericDAO;
 import org.navalplanner.business.orders.entities.Order;
 
@@ -9,4 +11,11 @@ import org.navalplanner.business.orders.entities.Order;
  */
 public interface IOrderDAO extends IGenericDAO<Order, Long> {
 
-}
\ No newline at end of file
+    /**
+     * Gets all the orders.
+     *
+     * @return A {@link List} of {@link Order} objects
+     */
+    List<Order> getOrders();
+
+}
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/orders/daos/OrderDAO.java b/navalplanner-business/src/main/java/org/navalplanner/business/orders/daos/OrderDAO.java
index 374645591..61db0af9d 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/orders/daos/OrderDAO.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/orders/daos/OrderDAO.java
@@ -1,5 +1,7 @@
 package org.navalplanner.business.orders.daos;
 
+import java.util.List;
+
 import org.navalplanner.business.common.daos.GenericDAOHibernate;
 import org.navalplanner.business.orders.entities.Order;
 import org.springframework.beans.factory.config.BeanDefinition;
@@ -14,4 +16,10 @@ import org.springframework.stereotype.Repository;
 @Scope(BeanDefinition.SCOPE_SINGLETON)
 public class OrderDAO extends GenericDAOHibernate<Order, Long> implements
         IOrderDAO {
+
+    @Override
+    public List<Order> getOrders() {
+        return list(Order.class);
+    }
+
 }
\ No newline at end of file
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/orders/entities/Order.java b/navalplanner-business/src/main/java/org/navalplanner/business/orders/entities/Order.java
index c31347e84..551176d7e 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/orders/entities/Order.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/orders/entities/Order.java
@@ -8,13 +8,15 @@ import org.hibernate.validator.NotEmpty;
 import org.hibernate.validator.NotNull;
 import org.hibernate.validator.Valid;
 import org.navalplanner.business.common.BaseEntity;
+import org.navalplanner.business.common.IValidable;
+import org.navalplanner.business.common.exceptions.ValidationException;
 import org.navalplanner.business.planner.entities.TaskElement;
 
 /**
  * It represents an {@link Order} with its related information. <br />
  * @author Óscar González Fernández <ogonzalez@igalia.com>
  */
-public class Order extends BaseEntity implements IOrderLineGroup {
+public class Order extends BaseEntity implements IOrderLineGroup, IValidable {
 
     private static Date copy(Date date) {
         return date != null ? new Date(date.getTime()) : date;
@@ -143,4 +145,18 @@ public class Order extends BaseEntity implements IOrderLineGroup {
         return false;
     }
 
+    @Override
+    public void checkValid() throws ValidationException {
+        if (this.isEndDateBeforeStart()) {
+            throw new ValidationException("endDate must be after startDate");
+        }
+
+        for (OrderElement orderElement : this.getOrderElements()) {
+            if (!orderElement.checkAtLeastOneHoursGroup()) {
+                throw new ValidationException(
+                        "At least one HoursGroup is needed for each OrderElement");
+            }
+        }
+    }
+
 }
diff --git a/navalplanner-business/src/test/java/org/navalplanner/business/test/planner/services/TaskElementServiceTest.java b/navalplanner-business/src/test/java/org/navalplanner/business/test/planner/services/TaskElementServiceTest.java
index 6580a69b7..9703139bd 100644
--- a/navalplanner-business/src/test/java/org/navalplanner/business/test/planner/services/TaskElementServiceTest.java
+++ b/navalplanner-business/src/test/java/org/navalplanner/business/test/planner/services/TaskElementServiceTest.java
@@ -18,12 +18,12 @@ import org.junit.Test;
 import org.junit.matchers.JUnitMatchers;
 import org.junit.runner.RunWith;
 import org.navalplanner.business.common.exceptions.ValidationException;
+import org.navalplanner.business.orders.daos.IOrderDAO;
 import org.navalplanner.business.orders.entities.HoursGroup;
 import org.navalplanner.business.orders.entities.Order;
 import org.navalplanner.business.orders.entities.OrderElement;
 import org.navalplanner.business.orders.entities.OrderLine;
 import org.navalplanner.business.orders.entities.OrderLineGroup;
-import org.navalplanner.business.orders.services.IOrderService;
 import org.navalplanner.business.planner.entities.Dependency;
 import org.navalplanner.business.planner.entities.Task;
 import org.navalplanner.business.planner.entities.TaskElement;
@@ -51,7 +51,7 @@ public class TaskElementServiceTest {
     private SessionFactory sessionFactory;
 
     @Autowired
-    private IOrderService orderService;
+    private IOrderDAO orderDAO;
 
     private HoursGroup associatedHoursGroup;
 
@@ -87,7 +87,8 @@ public class TaskElementServiceTest {
         order.setInitDate(new Date());
         order.add(orderLine);
         try {
-            orderService.save(order);
+            order.checkValid();
+            orderDAO.save(order);
             sessionFactory.getCurrentSession().flush();
         } catch (ValidationException e) {
             throw new RuntimeException(e);
diff --git a/navalplanner-webapp/src/main/java/org/navalplanner/web/common/converters/OrderConverter.java b/navalplanner-webapp/src/main/java/org/navalplanner/web/common/converters/OrderConverter.java
index 583284fa5..b3542a7e0 100644
--- a/navalplanner-webapp/src/main/java/org/navalplanner/web/common/converters/OrderConverter.java
+++ b/navalplanner-webapp/src/main/java/org/navalplanner/web/common/converters/OrderConverter.java
@@ -1,12 +1,13 @@
 package org.navalplanner.web.common.converters;
 
 import org.navalplanner.business.common.exceptions.InstanceNotFoundException;
+import org.navalplanner.business.orders.daos.IOrderDAO;
 import org.navalplanner.business.orders.entities.Order;
-import org.navalplanner.business.orders.services.IOrderService;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.context.annotation.Scope;
 import org.springframework.stereotype.Component;
+import org.springframework.transaction.annotation.Transactional;
 
 /**
  * A {@link IConverter} for {@link Order} <br />
@@ -17,12 +18,13 @@ import org.springframework.stereotype.Component;
 public class OrderConverter implements IConverter<Order> {
 
     @Autowired
-    private IOrderService orderService;
+    private IOrderDAO orderDAO;
 
     @Override
+    @Transactional(readOnly = true)
     public Order asObject(String stringRepresentation) {
         try {
-            return orderService.find(Long.parseLong(stringRepresentation));
+            return orderDAO.find(Long.parseLong(stringRepresentation));
         } catch (InstanceNotFoundException e) {
             throw new RuntimeException(e);
         }
diff --git a/navalplanner-webapp/src/main/java/org/navalplanner/web/orders/OrderModel.java b/navalplanner-webapp/src/main/java/org/navalplanner/web/orders/OrderModel.java
index 04a353de8..655d0cf01 100644
--- a/navalplanner-webapp/src/main/java/org/navalplanner/web/orders/OrderModel.java
+++ b/navalplanner-webapp/src/main/java/org/navalplanner/web/orders/OrderModel.java
@@ -11,10 +11,10 @@ import org.hibernate.validator.ClassValidator;
 import org.hibernate.validator.InvalidValue;
 import org.navalplanner.business.common.exceptions.InstanceNotFoundException;
 import org.navalplanner.business.common.exceptions.ValidationException;
+import org.navalplanner.business.orders.daos.IOrderDAO;
 import org.navalplanner.business.orders.entities.IOrderLineGroup;
 import org.navalplanner.business.orders.entities.Order;
 import org.navalplanner.business.orders.entities.OrderElement;
-import org.navalplanner.business.orders.services.IOrderService;
 import org.navalplanner.business.planner.services.ITaskElementService;
 import org.navalplanner.business.resources.daos.ICriterionDAO;
 import org.navalplanner.business.resources.entities.Criterion;
@@ -45,7 +45,8 @@ public class OrderModel implements IOrderModel {
 
     private static final Map<CriterionType, List<Criterion>> mapCriterions = new HashMap<CriterionType, List<Criterion>>();
 
-    private final IOrderService orderService;
+    @Autowired
+    private IOrderDAO orderDAO;
 
     private Order order;
 
@@ -57,24 +58,22 @@ public class OrderModel implements IOrderModel {
     @Autowired
     private IOrderElementModel orderElementModel;
 
-    private final ITaskElementService taskElementService;
-
     @Autowired
     private ICriterionDAO criterionDAO;
 
     @Autowired
-    public OrderModel(IOrderService orderService,
-            ITaskElementService taskElementService) {
-        Validate.notNull(orderService);
+    private ITaskElementService taskElementService;
+
+    @Autowired
+    public OrderModel(ITaskElementService taskElementService) {
         Validate.notNull(taskElementService);
-        this.orderService = orderService;
         this.taskElementService = taskElementService;
     }
 
     @Override
     @Transactional(readOnly = true)
     public List<Order> getOrders() {
-        return orderService.getOrders();
+        return orderDAO.getOrders();
     }
 
     private void loadCriterions() {
@@ -99,7 +98,7 @@ public class OrderModel implements IOrderModel {
 
     private Order getFromDB(Order order) {
         try {
-            return orderService.find(order.getId());
+            return orderDAO.find(order.getId());
         } catch (InstanceNotFoundException e) {
             throw new RuntimeException(e);
         }
@@ -121,8 +120,7 @@ public class OrderModel implements IOrderModel {
         InvalidValue[] invalidValues = orderValidator.getInvalidValues(order);
         if (invalidValues.length > 0)
             throw new ValidationException(invalidValues);
-
-        this.orderService.save(order);
+        this.orderDAO.save(order);
     }
 
     private void reattachCriterions() {
@@ -139,9 +137,10 @@ public class OrderModel implements IOrderModel {
     }
 
     @Override
+    @Transactional
     public void remove(Order order) {
         try {
-            this.orderService.remove(order);
+            this.orderDAO.remove(order.getId());
         } catch (InstanceNotFoundException e) {
             throw new RuntimeException(e);
         }
diff --git a/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/OrderPlanningModel.java b/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/OrderPlanningModel.java
index 0fcb4327a..49a8cfa72 100644
--- a/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/OrderPlanningModel.java
+++ b/navalplanner-webapp/src/main/java/org/navalplanner/web/planner/OrderPlanningModel.java
@@ -7,8 +7,8 @@ import java.util.List;
 import java.util.Set;
 
 import org.navalplanner.business.common.exceptions.InstanceNotFoundException;
+import org.navalplanner.business.orders.daos.IOrderDAO;
 import org.navalplanner.business.orders.entities.Order;
-import org.navalplanner.business.orders.services.IOrderService;
 import org.navalplanner.business.planner.entities.TaskElement;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.config.BeanDefinition;
@@ -26,7 +26,7 @@ import org.zkoss.ganttz.adapters.PlannerConfiguration;
 public abstract class OrderPlanningModel implements IOrderPlanningModel {
 
     @Autowired
-    private IOrderService orderService;
+    private IOrderDAO orderDAO;
 
     private PlanningState planningState;
 
@@ -160,7 +160,7 @@ public abstract class OrderPlanningModel implements IOrderPlanningModel {
 
     private Order reload(Order order) {
         try {
-            return orderService.find(order.getId());
+            return orderDAO.find(order.getId());
         } catch (InstanceNotFoundException e) {
             throw new RuntimeException(e);
         }