I recently re-plumbed my pool that had set empty for 2 years. When I started to let water go through the system, water dripped out from a hairline crack at the heater manifold where the 2" pipes connect. I am very certain that the crack was caused by a hard freeze sometime ago because my above ground pipe and valve also cracked.
A new heater is about $2000 and the part is about $300. If this is the only part I need to change, I will replace it. However, I just don't know if other components may also be damaged by the freeze or sitting idle for so long. Does anyone have any experience on heaters damaged by freeze?