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“Gateway serial number not valid” error during Vaillant onboarding

Fixing the gateway serial number error

Asma Mohamoud avatar
Written by Asma Mohamoud
Updated yesterday

If you see a “Gateway serial number not valid” message while connecting your Vaillant heat pump to Havenwise, don’t worry, this guide will walk you through what to do.

Step 1: Check if the PCB (Main Board) Has Been Replaced

The most common reason for this error is that the PCB (main motherboard) in your heat pump has been replaced since it was first installed.
If you’re not sure, your installer can usually confirm this.

  • If the PCB has not been changed, please close the app completely and try again.
    If the error continues, contact our support team.

  • If the PCB has been changed, follow the steps below.

Step 2: Ask Vaillant to Update Their System

When the PCB is replaced, the heat pump’s serial number sometimes stops matching what Vaillant has on file.
To fix this, Vaillant’s support team will need to update your details on their system.

Here’s how:

  1. Contact Vaillant Support

    • In the myVAILLANT app: go to Settings → Customer Support, or

    • On the myVAILLANT website: click Customer Support on the login page.

  2. Send Vaillant this message (you can copy and paste):

    Hi team,

    I’m trying to give Havenwise access to my heat pump system via the API, but I’m getting an “Invalid serial number” message. My aroTHERM+ unit’s main PCB has been changed, so the serial numbers no longer match.

    I confirm that:

    • I’m happy for you to re-add the serial number into the heat pump PCB.

    • My postcode and address line 1 are: [insert details].

    • I’ve attached an image of the unit’s label or a document showing the serial number of the heat pump.

    Please confirm once this has been updated so I can continue with Havenwise setup.

    Best,
    [Your name]

  3. Vaillant will update their system and confirm when this is done.

Step 3: Grant Permission to Havenwise

Once Vaillant has updated your details, you’ll receive an email asking you to grant Havenwise permission.

  1. Open the email from Vaillant.

  2. Click the link titled “Grant Permission”.

  3. Return to the Havenwise app and continue where you left off.

  4. If you still see the “Invalid serial number” message, close the app completely and reopen it again.

That’s it!
Once these steps are complete, Havenwise should connect successfully to your Vaillant system.
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If you still experience issues after following this guide, please contact our support team for further help.

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