Recent content by Yikes

Dear Mr Bunny Could you advise me on another mystery please, this time with the VRC470F weather controller. It gives longer burn times but the boiler fires up every 17 minutes before the HW cycle comes on at 5am. Any idea why? Mike

I've always struggled with the boiler settings so thank you for that advice. Regarding the pump speed, I reduced it to increase the temperature differential between flow and return. My heating engineer said it was fine on 1 and the house warms up just the same as it did on 2. I've now switched...

Sorry that's a typo. The target was set at 18C. Mike

I was right about the control board. I had it replaced and it fixed the problem. Not surprising really as it was 13 years old. Mike

Shortly after the heating came on this afternoon I reduced the modulation from 55% to 33% but the instability is still there. My heating engineer is going to replace the control board shortly so I'll leave it until then. Thanks for your input. Mike

OK I'll try reducing d.0 when it's stabilised. In the past I have tried many configurations, including weather control and return regulation but at the moment I'm keeping it simple until I'm confident it's working properly. Thanks. Mike

There is no Auto setting for d.0, it's just the part load in kW. Factory setting is 18 which is far too high for my system. 2-point control is like a conventional on/off thermostat. Flow temperature is set to 65C. The controller has an analogue mode which reduces the flow temperature as the...

d.0 is set to 10kW, hence the 55% modulation for CH (HW is 18kW). The controller is a VRT350f set to 2-point control. Mike

Happy New Year everyone and good luck with all your plumbing adventures. Regular visitors to this forum will know that I have an unhealthy obsession with monitoring my boiler's ebus. I noticed recently that the modulation during the CH on periods has a weird instability that has been getting...

Vaillant ecoTEC Plus 418 with VRT392f controller. Why does the return temp exceed the flow temp when the pump switches off? Does it matter? Mike

Sure, but I wondered what other people are seeing? Mike

What is a typical figure for the rate of increase in room temperature when a heating system starts up? A friend of mine said it should be 4degC per hour but mine only manages about 1degC per hour between 6am and 9am. Mike

The logic behind changing the NTCs was to see if modulation was reacting to flow temperature but as the behaviour hasn't changed it must be the other way round. If I saw that behaviour in an audio circuit I'd suspect a faulty decoupling capacitor. 100% modulation is 18kW but my boiler won't go...

Oh yes, this saga is never ending. I have tried just about every setting at one time or another. I do have a different thermostat I could try (a VRC470f with weather controller) but that would introduce even more variables and I don't think that's the problem. I did consider sending my graphs to...

I monitor the boiler remotely and I wasn't looking at the S codes. d.09 is the flow target temperature if determined by an external controller. So if I set my thermostat to analogue mode it would adjust the flow temperature down as the room approaches the set temperature. As my thermostat is in...