My central heating is an open vented system and is about 35 to 40 years old. It has been cleaned (with Fernox F3) and then drained down, so has been empty for some months now. I'm thinking about leaving it empty and unused over summer (I wont be needing any hot water from taps over that period).
I would like to know if it is safe to leave the system drained and empty. I presume there wont be any corrosion since there is no water in the system but could anything else undesirable happen if the system is empty for a prolonged period?
HELLO SEMOLINA --- this is a question which would be answered differently [correctly] by an engineer in one or more of the various technologies, which include central heating and hot water, in any system, of any size, in any country.
The reason is, there is ONLY ONE SCIENCE, technology and methodology follows known science.
Both Scientific, Metallurgical and Mechanical technology dictates that " DISSIMILAR BASE METAL ALLOYS CANNOT AVOID ELECTROLYTIC PARTICLE TRANSFER COMMONLY CALLED CORROSION " when exposed to variations in temperature and humidity.
Very experienced and qualified Central Heating engineers will know this, and they WILL advise you to keep your system FULL AND WORKING AND PERIODICALLY RUN WHEN SYSTEM IS NOT NEEDED [ SUMMER ETC. ].
They will also advise you to have an approved " CORROSION INHIBITOR " flushed into the entire system AFTER ANY FAULTS HAVE BEEN RECTIFIED. A good example of maintaining a working system is RUN IT FOR ONE HOUR - MONTHLY.
Please post to me ANY Engineering question you may have, including more Science on the above if you would like to know.