Significant speed drop after unplugging router for a week

[#1]

I had to unplug the router because there were building works going on in the room where the master socket is.

During this time when the router was unplugged, the router downstream/upstream sync speeds dropped from 80/20 (which the Openreach engineer confirmed on his device during installation of the socket) to about 40/9. Speeds are now at 48.89/10.35 but this is still far below the 80/20 speeds I had for nearly 2 months after installation of the socket and initial activation.

Emails I have from Plusnet also state the following:

We estimate your broadband speed should be between 68 Mb and 80Mb and your minimum guaranteed access line speed is 60Mbps. 

&

66Mb average download speed

 How can I get my speeds back up to what they were before? I am on the most expensive package yet not getting the stated speeds...

[#2]

I would check your wiring carefully. Sounds like something has changed with your wiring possibly during the building work which is causing the problem. Have you tried connecting the router to the test socket only ? What work have you had done - anything that could have caused damp in the master socket such as plastering ?

[#3]

I have not tried connecting the router to the test socket only. I'm not keen to unplug it as the power was turned off the other day and the speeds dropped when I plugged the router back in again!

The builders screeded the floor and some plastering was done to patch up some small inspection holes but far away from the master socket (opposite side of the room). I have checked all the wiring and it all looks in tact. I don't think it would have got damaged as the cabling sits above skirting board level.

[#4]

The speed has dropped due to errors/noise on the line, until you fix the issue the speed won't recover. In fact the longer it's like that the longer it will take to eventually recover due to DLM responding to the errors.

I would disconnect everything and check that your builder hasn't been playing while you weren't looking. I would definitely check he hasn't shorted something across the extension wiring, which is why I suggested checking at the test socket.

[#5]

I only have one socket (Master Socket 5C). I have just tested through the test socket with a microfilter and speed has gone from 49.53/10.63 to 49.20/11.95.

One thing I have noticed is that the internet has disconnected several times at 3am with a marginal speed increase on reconnection. Could it be that the speeds are slowly recovering after the router has been disconnected for a week?

[#6]

The resyncs at 3AM will be the DLM trying out different things. If it's backing out things it should get progressively better until you get back to 80/20 - it can take up to a couple of weeks to back out really aggressive DLM actions.

There is no way just disconnecting the router should have caused this unless there was a High Resistance fault on the line previously that was being covered up by the whetting current. Something is going badly wrong for the sync to have dropped that much. Some other things to look at:

Do you have a spare router just to check the router hasn't developed a fault whilst it's been unplugged ?
What are your router stats like - can you paste the information from the help desk page.
Can you plug a phone in and dial 17070 option 2. Do you hear any unusual noise on the quiet line test ? If so try running a line test using the PlusNet online tester.

[#7]

The speed has dropped because your router was disconnected. To DSLAM equipment at the exchange, it meant that there was no sync and so came across as problems on the line. 

You should ask Plusnet to have your profile reset or wait a few weeks and the speeds will be back up again. Don't disconnect your router during this time.

The 3am disconnection is a maintenance one. 

The above highlights that the router should be connected to the socket all the time (some people switch it off overnight which is wrong).

[#8]

DLM doesn't make changes due to the router being disconnected - it should see the week disconnection as just that, router turned off = no data.  I do agree with Edinburgh_wg that routers should normally be connected at all times, otherwise DLM will see the regular disconnects as evidence of a faulty line and take action.  For full details of how DLM works please see https://community.plus.net/t5/Library/FTTC-DLM-What-it-is-How-it-works/ba-p/1322799

In this instance a large amount of noise has been introduced on the line since the router has been reconnected, and DLM may well have intervened - finding out why is the challenge here.

In the worse case and DLM doesn't recover then I believe PlusNet can now request a DLM Reset, but I wouldn't do that until I was absolutely sure I didn't still have a faulty line/wiring/router - otherwise you will be back in the same position within a week or so...

[#9]

Thanks for your post @chrisr22 and welcome to our Community Forums.

I'm sorry to see you're having speed issues.

I've tested your line today and the tests are actually showing an external fault, so I think the building work you had may be a red herring. The type of fault I've detected is what's known as a "Dis one leg in network" so I've raised this across to our suppliers, and we've been given an estimated response time of by 04/01/22 23:59:59 for an engineer to investigate further.

We'll provide an update as soon as we know more, but feel free to post back here with how things go. 

[#10]

Thank you for looking into this. I await further updates once you know more 😄

[#11]

No worries @chrisr22, if you have any further queries in the meantime at all, don't hesitate to get back to us.

[#12]

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@Gandalf wrote:

The type of fault I've detected is what's known as a "Dis one leg in network"  

---

Which would have been immediately obvious from doing a basic "Is the phone line working" test first.  Broadband can limp along with just one side of the circuit connected, albeit slowly!  A Quiet Line Test is also the most pragmatic way of checking a line for noise as mentioned by several posters on here as being a potential contributor.

Issues such as this illustrate the essential importance / merits of having a telephone handset available / plugged into the line, irrespective of any intention to use the phone service.

[#13]

Fixed now and back up to 80/20 speeds. Thanks everyone.

[#14]

Thanks for the update @chrisr22, that's good to hear!