Timeout occur sometimes when executing a Store Procedure - sql

Question

I have this stored procedure, which works if I execute manually. But sometimes I see timeout exception on running this Stored Procedure. Is this is due to MERGE, http://www.mssqltips.com/sqlservertip/3074/use-caution-with-sql-servers-merge-statement/
ALTER PROCEDURE [dbo].[InsertOrUpdateMobileUser]
(
#ID BIGINT
,#Name NVARCHAR(255)
)
AS
BEGIN
SET NOCOUNT ON;
DECLARE #TranCount INT;
SET #TranCount = ##TRANCOUNT;
BEGIN TRY
IF #TranCount = 0
BEGIN TRANSACTION
ELSE
SAVE TRANSACTION InsertOrUpdateMobileUser;
MERGE INTO MobileUsers MU
USING (SELECT #ID AS ID) T ON (MU.ID = T.ID)
WHEN MATCHED THEN
UPDATE SET [Name] = CASE WHEN #Name IS NULL OR #Name = '' THEN [Name] ELSE #Name END
WHEN NOT MATCHED THEN
INSERT ([Name])
VALUES (#Name)
SELECT *
FROM MobileUsers
WHERE ID = #ID;
LBEXIT:
IF #TranCount = 0
COMMIT;
END TRY
BEGIN CATCH
DECLARE #Error INT, #Message VARCHAR(4000), #XState INT;
SELECT #Error = ERROR_NUMBER() ,#Message = ERROR_MESSAGE() ,#XState = XACT_STATE();
IF #XState = -1
ROLLBACK;
IF #XState = 1 AND #TranCount = 0
rollback
IF #XState = 1 AND #TranCount > 0
ROLLBACK TRANSACTION InsertOrUpdateMobileUser;
RAISERROR ('InsertOrUpdateMobileUser: %d: %s', 16, 1, #error, #message) ;
END CATCH
END

Answer 1

You differentiate between two execution methods. What are they, exactly? You mean that it works if run only the code of the procedure, and doesn't work when you EXECUTE the proc? Of it works through EXECUTE, and fails in a job?
Timeouts only concern client applications. You have SqlCommand .CommandTimeout property in .NET, and in Management Studio there's Tools>Options>Query Execution>Command Timeout. If you have a job, then it should run infinitely, there's even no option to set the timeout in Sql Server Agent.