The manufacturer is claiming "thermal shock" is the cause of this problem. It has not been determined beyond a reasonable doubt that this is the problem. We will be visiting the jobsite soon, and the cracked section has been saved. Perhaps our observation of the crack size, type and location...
We have recently designed the installation of a cast-iron sectional boiler an have experienced multiple crackings of the sections. The manufacturer of this boiler insisted that blend pumps be installed, despite the fact that the boiler has a three-way valve on the supply that diverts hot water...
