Runspace opening multiple remote powershell connections and not closing them

Question

Hello,
I hope this has not already been asked as I have been searching for good amount of time.
I have an asp.net site that runs some remote PowerShell scripts. Below is the code I Pass the script to. Everything works fine except it does not close all connections.
When I do a netstat -ao I see that each time this is called it leaves 2 sessions opened to the remote server. I go on the remote server and do a Get-PSSession and do not see any of the sessions opened. When stepping through the code, "pRunspace.Open()"
creates 2 connections to the destination server, Then the "psresult = pShell.Invoke" creates another open connection. The Dispose() only closes one of the 3 connections. Upping the amount of connections or changing the idle time on the receiving
server is not an option as I have already increased/lowered them and it still gets maxed connections. . iisreset clears the open connections. I have tried .disconnect() but the destination does not have PowerShell 3.0. Am I missing something stupid here? Is
there a better way to go about this. 
Any help is appreciated.
Thank you,
Mike
Public Shared Function RunRemotePSScript(ByVal script As PSCommand, ByVal ServerURL As String, ByVal shellurl As String) As String
Dim pCredential As PSCredential
Dim pConnectionInfo As WSManConnectionInfo
Dim pRunspace As Runspace
Dim pShell As PowerShell
Dim securepass As New System.Security.SecureString
Dim serverUri As New Uri(ServerURL)
Dim psresult As New System.Collections.ObjectModel.Collection(Of PSObject)
For Each c In "Password"
securepass.AppendChar(c)
Next
'-- set credentials
pCredential = New PSCredential("Domain\username", securepass)
'-- set connection info
pConnectionInfo = New WSManConnectionInfo(serverUri, shellurl, pCredential)
'-- create remote runspace
pRunspace = RunspaceFactory.CreateRunspace(pConnectionInfo)
pRunspace.Open()
'-- create powershell
pShell = PowerShell.Create
pShell.Runspace = pRunspace
'-- add command to powershell
pShell.Commands = script
Try
'-- invoke the powershell
psresult = pShell.Invoke
pShell.Dispose()
pRunspace.Close()
pRunspace.Dispose()
Dim sb As String = ""
For Each result As PSObject In psresult
sb &= result.ToString
Next
Return sb
pShell.Dispose()
pRunspace.Dispose()
pRunspace.Close()
pRunspace = Nothing
Catch ex As Exception
If Not IsNothing(pShell) Then
pShell.Dispose()
End If
If Not IsNothing(pRunspace) Then
pRunspace.Dispose()
pRunspace.Close()
End If
Return Err.Description
End Try
End Function
That is the netstat output I get after running through the function one time.
c:\Windows\system32>netstat -ao |findstr Server1
  TCP    MycomptuerIP:49307    RemoteServer1:http           ESTABLISHED     7632
  TCP    MycomptuerIP:49312    RemoteServer:http           ESTABLISHED     7632
Here is an example of how i call the function. 
Public Shared Function Set_UM_PinNumber(ByVal UserSamAccout As String, ByVal PinNumber As String) As String
Try
Dim output As String = ""
Dim psh As New PSCommand
psh.AddCommand("Set-UMMailboxPIN")
psh.AddParameter("Identity", UserSamAccout)
psh.AddParameter("Pin", (PinNumber))
psh.AddParameter("PinExpired", 0)
output = AD.ADWrapper.RunRemotePSScript(psh, "http://Server.domain.com/powershell?serializationLevel=Full", "http://schemas.microsoft.com/powershell/Microsoft.Exchange")
If output = "" Then
Return "Pin Updated"
Else
Return output
End If
Catch ex As Exception
Return Err.Description
End Try
End Function

Answer 1

Fred, 
Thank you for taking time to reply. From what I got and tested "The EndInvoke method
is used to retrieve the results from the completed runspace" Then you clean up after that.. Close is supposed to close all the connections. But I could be very wrong. I am self taught and
truly could be going at this all wrong. This was working in the past ( could be that more people are using it now that I am seeing the connections full). I really hope someone can help me or direct me in the right direction as this is causing a lot of problem
for me.
Mike