DIY Doctor UK DIY Forums

We have a VRC430 Weather Compensator control panel installed on our Vaillant ecoTEC Plus 837 boiler and also have a VR81 remote control unit installed in the living room.

1. What is the relationship and interaction between the programmed times for heating and hot water, and the two big control dials on the left handside of the boiler control panel? For example, what temperature does the hot water go to if the time programme dictates 52 degrees, but the temperature control dial on the left is set to, say, 45 degrees? Similarly for the heating: the heating dial on the left is turned to the lowest setting (30 degrees) and the time programme for heating is set to, say 18 degrees. Which setting takes precedent?

2. In relation to the question above, the radiators do not start heating up until the bottom-left dial is turned up, even though the target temperatures on both the time programme and remote control unit have been set to well above the actual room temperature. What's going on?

3. Section 4.3.3 in the user manual for the VRC 430 Weather Compensator states that the display should return from the basic display to the default display after 5 minutes or by clicking either dial. This does not happen. In fact, I've never seen the default display. Can you clarify?

4. Should the room temperature control (Menu C8 - HC1 parameters) be set to 'none', 'modulating' or 'thermostat'?

5. In menu A5 ("Installation Assistant Module Test Menu") there is an option for Heat Source Choice, which can be set to either 'OFF' or '50 degrees'. What does this mean and what value should I select?

6. The heating is set to automatically go on at 15 degrees, but it seems to kick in when the outside temperature falls below 15 rather than the inside temperature. (I have two sensors). Could they be connected incorrectly? What's going on?

1. Both dials for water and c/h must be turned fully clockwise when VRC 430 is fitted. This way the programmed temperatures are used by the 430.

2. If the bottom left dial is turned down any amount the VRC 430 is not given its full operating range capability.

3. The default display screen is only, repeat only, available when the VRC 430 is wall mounted... this way it acts as a room thermostat too.

4. I have set mine to thermostat, as the VRC 430 is acting as the room stat and, for example, provides the target room temperature.

5. This is for testing only, leave it set to off.

6. I assume the 15 degrees is your set back temperature... ie the boiler will fire up even when not on a time programme. If not set c/h uses 5 degrees for frost protection. Sensors 2 ? VRC430 has outside temp sensor, VR81 is room stat sensor, boiler monitors temp of flow and return... have I misunderstood you?

Thanks, watcha - that was useful

thanks watcha