There is another concept of moving the Equipment (Serialized Material) from one storage location to another storage location by using movement types 313 & 315.
Check the below links & configure Additional movement types for Refurbishment order. In this case, cost will not be posted as Expense as this is just stock transfer & still it is in warehouse under blocked stock.
http://help.sap.com/erp2005_ehp_05/helpdata/en/4a/9f2170952b6c3de10000000a42189c/content.htm
http://help.sap.com/erp2005_ehp_05/helpdata/en/e8/00e93a2876a81ae10000000a11402f/content.htm