Faulty Junkers water heater

Your issue will be on the input or mains supply side of your electrics.
Check your wiring for keakage to earth.

these units have an inlet filter i would check that first, 2nd i would turn on 3 hot water sources and see after doing see if it corrects last try resetting the unitit. the 3 - 220 circuits are for the heating elements.

Check pilot is clean and strong Also check sensor is clean and connections are clean and tight .

Is it gas or electric? if it is gas and has a pilot, and the pilot is out. If you don't smell gas go through the start pilot proceedure. when the pilot is running it produces a small electric current sufficient to hold the main gas valve open; then the temperture sensor allows the unit to keep the water heated.

http://documents.junkers.com/download/pdf/file/7181465057.pdf Sometimes there are several parts on this model to find buit beware on some marketing technical made differences inbetween one year of build there can be some modifications inside.

Succes

i have a junker water heater. what side does the cold water pipe go the the geyser

Most electronic ignition models only show the red light if there is a problem, (did not ignite) for one reason or another. To start with, make sure your propane is on, and you have a good flame at stove top burner, just to be sure the water heater is getting propane, and all air is bled from the line, which may cause water heater to go into check. (red light) If it does, shut switch off, and retry. Let me know what happens. As far as pressure relief opening and emptying the water heater, and your sure it's not a faulty pressure relief valve, then there's 2 things to start with checking. 1st, does the water seem extremely hot, thus a possible faulty thermostat &/or ECO . Secondly, if the incoming water pressure is too high, that will also cause it to leak bad. Try installing a pressure regulator (usually 40 psi.) at your hose connection. Let me know what you find.

After it is stored for the 2 weeks, do you turn water on to it, then bleed out any air through the taps before lighting it? If not try that and see what happens and let me know if any different.

sounds like one of the saftey relays might be going bad. or the ingniter might be cracked or need cleaning

Yes that is going to be the contoll valve on that heater. You can probley fix it very easy with the right part. You will need to locate a plumbing supply over there in the UK. Give them the make and model number and tell them you need a unitroll gas valve for it.