Adsibob

Indeed! And on calling them this morning they did speak to a technical guy who said it sounded like a manufacturing problem. My installer is abroad till 10th Jan, and I really don’t want to take any chances (with gas leaks or loss of heating/HW over the next couple of weeks.

I called Veissman and they think it might be a manufacturing fault so are going to send out an engineer on Monday under the 12 year warranty I paid for. Of course if it’s not a fault, I get charged £144! You may be right about local gas supply. If there is a sudden drop in temperature as we had, everyone will suddenly use more gas.

Sorry my mistake. I think I calculated heat loss PLUS requirements to heat the cylinder at about 15kw and decided to go with a 18kw boiler. My gas engineer /installer laughed at me, and insisted it wouldn’t be enough. I think he was wrong but he’s the so called professional, so I just accepted his view.

Yea, I discovered the usefulness of this for the very first time yesterday. Once we had got the boiler working again, it powered up to 90% modulation, the highest I’ve ever seen it modulate to. I guess with the water temperature from the mains being quite cold, the house having an average temp of 17.8C and the UWC being cold, it needed quite a bit of power to heat everything up. It’s a 1920s semi that has been extended at the back on all levels. The back is therefore built to modern standards, but the rest, although covered in some 45mm of EWI and very airtight with MVHR, is ultimately solid wall construction, no cavity. Maybe the heat loss is only 15kw, but I erred on the side of caution, got to 18kw then my heating engineer practically doubled it! No short cycling thank god. But we didn’t make the most of the boiler’s capabilities unfortunately. I trusted the installer too much and didn’t commission a proper design. Had I done that, we would have got the benefit of WComp and low temperature heating. Instead we are heating water to 65C and sending that to the UFH manifolds where it is mixed down to about 35C. Silly really, but I’ve learnt my lesson now!

Just quite annoying that we came home to a cold ish house and no hot water. Turns out the fault had developed almost 36hr prior to that and even though it’s very cold outside, the house is sufficiently well insulated that it took that long for us to notice. Anyone know what I need to sign up to the boiler’s alert system? Is connected to the WiFi so might as well get that alert functionality working.

I hope you are right. I will call Veissman in the morning

Funnily enough, this has solved the issue. But I’m still concerned given the fault is something to do with a gas valve. If the gas valve is faulty I rather not run the boiler! Hmmm… what now?

We have a Veissman Vitodens 200-W system boiler. Installed new 3 years ago, only used for 2.5 years. At 35kw massively oversized, so rarely modulates above 40% (this was not intentional, I mistakenly followed my heating engineer’s advice and went much bigger than the 19kw my heat loss calcs showed). It has been serviced each year and still under warranty. But not much use the week before Christmas. Do I get it repaired by whoever I can find and then sue Veissman?!? Ffs! Here are the error messages:

You will need to drill through the floor to find a way. You really don’t want stagnant water anywhere near this system.

Not sure. Can you run a drain pipe upwards? Seems odd to me.

The boost switches have probably just been wired incorrectly. They should be retractive switches, but there are different types so maybe the wrong retractive switch was used, or the right one was used but incorrectly wired. Easy enough to fix. I would just ask them to come back and address boost issue first and then any other issues. If you want an objective reading on the sound, you can get a decibel meter from Amazon for about £12.

This is your problem. It is normal in my experience at least for the system to be audible when boosted. But you should only boost it occasionally, after a very smelly session in the toilet, or a long steamy shower. Fix the boost issue first.

Thanks @ProDave so is that sufficient to serve an oven that has a “total electricity loading” of 3000W?

This close up is in sharper focus k in case any of those font size 8 characters mean anything:

Here are two photos, one showing the whole CU and the other a close up. I’m concerned given the labelling that the sparky has wired it for a microwave and not for a combination oven: