Follow the steps under to rebuild your Office Web Apps 2013 farm in case you need it.
Step 1: Take farm offline (only if there is a load balancer in use)
Step 2: Collect the current Farm information via Powershell (This you have to do on the WAC Server):
Get-OfficeWebAppsFarm > c:\MyOWAfarm.txt
Step 3: Use Powershell (on the WAC Servers) to remove each child machine
Remove-OfficeWebAppsMachine (On each child machine)
This step you only have to go through if you have a multi server farm in your Office Web Apps farm
Step 4: Use Powershell (on the WAC servers) to remove the parent machine
Run the following command in Powershell to delete the farm:
Then Restart the OWA servers.
Step 5: Recreate the farm via Powershell (on the WAC Server)
If you want you could use the parameter values from “MyOWAfarm.txt”.AppsMachine
New-OfficeWebAppsFarm -InternalURL “http://karm-OWA.sharepoint.com” -AllowHttp -EditingEnabled -OpenFromURLEnabled
Replace http://OWA.sharepoint.com with the value for your OWA server.
Step 6: Add all the other servers to the OWA-farm via Powershell (on WAC Server). Run this from each child server:
New-OfficeWebAppsMachine -MachineToJoin <ParentServer>
Replace the value of <ParentServer> with your name of your ParentServer
Step 7: Bring farm back online.
You may want to rebuild the bindings via SharePoint Powershell (this you have to run on the SharePoint 2013 Server)
Disconnect SharePoint from the OWA farm:
Reconnect SharePoint to the OWA farm:
New-SPWOPIBinding –ServerName “KARM-OWA” -AllowHttp
Congratulations you have successfully recreated your Office Web Apps Farm.
Configure Office Web Apps for SharePoint 2013