5 things that crack on a hot water unit when it freezes

Water expands roughly 9% as it turns to ice, and it splits whatever is holding it — a hairline crack you'll never see until the machine is back under pressure and weeping at the seam. On a hot water unit, five spots take that damage almost every time, and they take it in a fairly predictable order.

1. Pump manifoldTrapped water in the head has nowhere to go. A cracked manifold means the pump comes off the machine before it runs again — this is the expensive one on the list.
2. UnloaderIt holds a column of water between the seat and the piston, sitting still, which is exactly the condition ice needs. A cracked unloader housing is usually the first thing we find on a bench in November.
3. CoilHot water units keep water in the coil between uses. A frozen wrap can split without leaking a drop until the machine is back under load — it's why we pressure test a coil rather than just looking at it.
4. Hose reel and fittingsStanding water in the swivel and the first few feet of hose freezes fast because it's exposed to the air. Cracked swivels and split hose ends are the cheapest fix on this list and the most common.
5. Float tank and inletA tank left full over a hard freeze can crack the tank itself or split the inlet fitting, and it's often not noticed until the next startup floods the pad.

Why this list matters now

Central Pennsylvania usually sees its first hard freeze in mid-to-late October. None of the five items above are expensive to prevent and all of them are expensive to repair after the fact — a cracked pump manifold or a split coil is the single most preventable repair bill we write every year.

We wrote the full drain-and-antifreeze procedure, plus what a drop-off winterization actually covers, on the winterization & freeze-repair page. If a freeze already got to a machine, that page also covers what a rebuild or a coil pressure test looks like — book it here or call and describe what you're seeing.