Thermor boiler water usage issue

Hi Everyone,

I am currently renting a place in Europe. The property, which is a cottage on the landlord’s property, is fed by a spring, but due to a prolonged drought, the spring has been reduced to a trickle.

As a result, we’ve been very careful with water since summer, but the other day, our landlord called us and asked what we were playing at, because our water usage had gone up from about 150 litres a day, to over 600l. We were very surprised, as we hadn’t used much. over the next few days, we used less and less water, and although the reported usages dropped too, it was still a lot over what we were using.

Our landlord checked the meter by having us use no water for an hour while they filled up several jerrycans, and the reported consumption for that period matched the amount in the jerrycans, so the meter is accurate, and there doesn’t seem to be a leak.

There is a 200L 15 year old Thermor electric boiler for the property that heats water off peak, from 10pm to 6am, and then provides water during the day. My working assumption is that there’s something with the expansion chamber, or pressure valve, or inlet or something that causes it to give up water when heating. Maybe the more hot water we use during the day, the more water it wastes or something like that, because, like I said, our water use does affect the total, and it’s not a fixed number above our actual use. In other words, if we use 50l, it might says 130l, which is 80l more, but if we use 200l, it might says 600l was used.

Our contract renewal is coming up, and this is making things somewhat fraught, so I’d really appreciate any ideas, suggestions, or advice, anyone can provide.

Thanks a lot