One night I forgot to drain the Rinnai water header when leaving the boat and the next time I visited the water in the heater exchanger had frozen and split the two half-found copper pipes at the top left of the heat exchanger.
Given that a replacement HE is around £100 (expensive when the entire heater can be had for around twelve that amount), Graham "the gas" Freeman suggested that the HE was eminently repairable. It looked like one of the pipes had already been repaired in the past with a blob of solder which had failed.
The HE is made of copper and, after the pipes were thoroughly cleaned a patch was soldered over each split (copper or brass will do). I used phosphoric acid flux and both a high-wattage mains iron and a gas-fired pencil iron to ensure both that the patch was secure and the edges filled with a fillet of solder. I did the repairs with the HE removed but this was merely to made access easier.
To date these repairs have lasted well and have shown no tendency to fail. For anyone out there who can turn their hand to some soldering then it is well worth attempting a repair to save the cost of a new HE.
or take it to a car radiator repair gaff,last winter i failed to drain our paloma properly and the inevitable hapened,took it to a radiator place on dock rd in liverpool,burst in three places,repaired inc new section of approx 6" being inserted,pressure tested,£30 a bargain in my opinion.has been spot on ever since.
The strongest repair to copper is to use copper stick. It has to be heated to cherry red then the copper stick applied witch runs as if it was being brazed and you don't need any flux. I use to use it on refrigeration joints
Rinnai Heat Exchanger repair
Posted - 12 Feb 2012 : 11:37:52
