France in Focus

I recently put a new thermostat on the water heater, one of these large white double pole blocks, that just fixes under the base. Having returned from a trip, I did switch the breaker off for the heater at the board, and back on when we returned. Next morning, no hot water, reset button on stat had opened, reset by pushing in, ok for 2 days now cold water again. I suspect the only reason it is going out is due to excessive heat but cant remember if it can be adjusted down or not? Any suggestions.

You seem to have big problems recently. It sounds like you may have offended the plumbing fairy.
Wish I could help but sadly I can't.

thermostats generally have an adjustable set point and a maximum trip point, which should also be adjustable. Do you have solar panel hot water heating? This can cause the thermostat to reach trip temperatures when we have lots of hot sun. You write that the thermostat is new so it would be wise to RTFM. I’m sure you will find how to do the adjusting in the manual. It sounds like you need to raise the trip temperature to avoid the unit cutting out.

Bit of the problem solved, it does help if you reset the breaker in the consumer unit. I will leave well alone and see if it comes on OK overnight.

There are two thermostats involved: the one to set the temperature at around 65 C or a little bit lower. Not lower than 55 C, legionella waiting. Some thermostats have a little scroll wheel for fine tuning of the temperature range. Turning left/right several times might help to get rid of an intermittent contact(resistance) problem.

It is a series connection: the other other one is the safety thermostat with a fixed preset temperature of 90 C. Switches off if the adjustable temperature thermostat keeps on heating, defective. The red push button is for the safety thermostat. Sometimes nuisance triggering, pushing this button can be the solution.
Resistance measuring to be sure what is going on or not. Let the boiler cool down, switch the MCB to off and measure the stat with a simple continuity test. Should be close to zero Ohm. The same procedure for the boiler heating element, resistance between 15 Ω and 100 Ω.

MCBs of the lower ranking species (Deblex and others), special offers, only 4 euros, avoid them. Always problems, not doing anything, intermittent faults or switching off at too high or too low currents. Question: does yours feed the hungry boiler, open the tableau électrique and check the two output contacts of your 16 or 20 amp MCB. A far better solution: use Schneider, Legrand, Hager, ABB or Siemens.

For those with a contacteur jour/nuit (hc/hp) read this:

Two almost identical wiring diagrams to connect the contacteur jour/nuit for a chauffe-eau électrique. For a modern digital meter and the slightly older arrangement with dial meter and a separate relais de découplage. For a triphasé chauffe-eau, this is the connection diagram. During heures pleines, the relay contact on the user side is open, easy to measure yourself by flipping up the protective cap at the bottom: then the full mains voltage is across it. During the heures creuses, the relay is energised and you obviously measure zero volts across these two terminals. With the SAGEM digital meter (and the new Linky smart meter) the same story. There, it is about the contact points C1 and C2 under the bottom cover. What is under the top lid is off limits to the user. Occasionally, the coil (bobine) in the contacteur jour/nuit is broken. This is easy to measure: between contact points A1 and A2 a resistance of about 3200 Ohm. But first switch off the main switch. Incidentally, you can also measure things with the mains voltage, see here for a further explanation in French. Then you can check whether the control signal in the meter is doing its job. If the switch in the meter behind the two connection points C1 and C2 is doing its job, a possible problem lies in the wiring or the distribution board of the house installation. If the control signal turns out to be completely absent for several days, sometimes just overnight - then it is time to contact the network operator ENEDIS. Sometimes it is only a temporary ENEDIS problem: a day later and everything is back to normal. Or the little glass fuse inside a SAGEM meter, to protect the so called fil-pilote signal (wake up / shut down) is defective, easy to replace.

According to the French regs (NFC 15-100), connecting such an electric boiler (à accumulation) or a flow-through device (instantané) is not allowed via a socket.

Take the thermostat off again........?

Yes I will have to get under and take the stat off again and see if I can alter the safety thermostat, as that is what is tripping out. As per normal I buy something from Amazon, then read the customer reviews, there are several on this product lasting 2 months and then nuisance tripping, which is what I am getting.

Amazon is good for speed of delivery, moderate for price, and apalling for quality control.

But good for getting your money back. In my experience.

The quality of yesterday. Our chauffe-eau made by Sauter (mentioning 220 V, not 230 V) decided that it was time to say farewell to us. Here in demolition position. Much too heavy, brute force method. Respectable age of 29 years. Quality, no complaints, original components kept doing what they were supposed to do. It was a 200 litres boiler, always more than plenty of really hot water. A non-adjustable stat, fixed temperature oi 80 C as I noticed when reading the specs at the bottom of the boiler. Hiding inside the plastic bottom. Lots of hot water, lots of electrons..... What emerged from the inside of the boiler makes it clear that sometimes a water filter is not a luxury.

Leroymerlin and others here in France also have thermostats for boilers made by Atlantic, Thermor, Sauter and the rest of this French family. Probably a better quality compared with Amazon no-name products.