Troubleshooting Your Central Heating System: VR66 Not Calling for Heat (2023 Update)

[Anonymous]

Hi, i have had a new boiler and central heating system fitted, with an agreement with the installer that i was to complete the wiring.

I am a competent electronics engineer of some 30 years standing.

The system consists of a Vaillant ecotec plus 428 boiler a Vaillant VR66 controller and a VRT350 remote room thermostat and timer, not wireless. I have proved that there is communication between the VR66 and the VRT350 by turning hot water on and off and turning the tank stat up

My problem is that i cannot turn on heating, there is no output to the 3 port diverter valve to change water flow and presumably no communication to the boiler to start working when heating is required this all points to a software glitch but without more information it is going to be difficult to pin down.

Has anyone had this problem before and what did you do ti correct it, i have already fitted a new VR66 without any success, without any information of internal circuitry and logic i am stumped...............................HELP please

[Theo]

7 years on, but did you ever figure this is out? I have a similar issue.

[HomeOwnersHub Advisor]

Before we dive into things, I want to make sure you know that my advice is based on the information you've given me, so if you've got any more relevant details, don't be afraid to share 'em.

Alright, let's get started. So, it sounds like you've got a Vaillant ecotec plus 428 boiler, a Vaillant VR66 controller, and a VRT350 remote room thermostat and timer. You mentioned that you're able to communicate between the VR66 and the VRT350, so that's a good start.

But now you're having trouble turning on the heating and getting any output to the 3 port diverter valve. Based on what you've shared, it's possible that there's a software glitch somewhere in the system.

Now, let's talk about your options. You've already tried replacing the VR66 without success, so the next step would be to further troubleshoot the issue. Here's what I suggest:

1. Check all of the wiring to make sure everything is properly connected and secure.
2. Double-check the programming on the VR66 controller to make sure it's set up correctly.
3. Test the diverter valve to make sure it's functioning properly.
4. If all else fails, it might be time to call in a professional.

If you do decide to take matters into your own hands, here are the tools and materials you'll need:

• Screwdrivers (flathead and Phillips)

• Wire cutters/strippers

• Electrical tape

• Multimeter

• Replacement diverter valve (if necessary)

Now, I want to make sure you understand that attempting to fix this issue yourself does come with its own set of risks. If you're not comfortable or confident in your abilities, it might be best to call in a professional. But if you're up for the challenge, go ahead and give it a shot!

So, to sum things up, if you're experiencing a VR66 not calling for heat, there are a few things you can try before calling in a pro. And if you do decide to tackle the issue yourself, just make sure you're properly equipped and prepared. Good luck, partner!