Winterize
A guided diagnosis for RV techs. Each step is a check, a reading or a question.
- What do you need? Pick the job.
- Which method? Both work. Blow-out leaves no taste; antifreeze protects traps and the pump that blow-out can miss.
- Bypass the water heater first The heater holds 6-10 gallons you do not want to blow around. Set the bypass valve(s) at the back of the heater to BYPASS. If there is no bypass kit, drain the heater fully via the anode/drain plug. Expect: Heater isolated from the lines
- Drain everything Open all low-point drains (usually two, red/blue or marked), the fresh tank drain, and the hot and cold low points. Open every faucet to let air in. Leave them open for the blow-out. Expect: Water stops running everywhere
- Bypass the water heater first Same as the blow-out: set the bypass so you do not fill the heater tank with antifreeze. Expect: Heater isolated
- Set up the antifreeze pickup Most coaches have a winterizing valve that lets the pump draw from a jug via a hose. If not, disconnect the pump inlet and put a hose into the jug. Expect: Pump draws from the jug
- De-winterize: what was used? Ask what was done in the fall.
- Check before use Blow-out leaves the system empty. Before pressurizing: bypass back to NORMAL, close every drain you opened, and check the anode/drain plug is in. Expect: All drains closed, plug in, bypass normal
- What froze and what is wet? Find every wet spot. Freeze damage shows as split PEX or PVC fittings, a cracked pump body, a split water heater fitting, or a cracked toilet valve. Expect: N
Causes and repairs
Blow-out procedure
With a regulated adapter on the city water inlet at 30-40 psi MAX, blow each faucet (hot then cold), the toilet, the shower, and the outside shower until only mist comes out. Do the city inlet last. Done when no water mist appears anywhere.
Tools: regulated air adapter
30-40 psi only. Open one fixture at a time. Finish with the toilet valve - it holds water in the mechanism.
Antifreeze procedure
With the pump drawing from the jug: run every faucet (hot then cold) until pink flows solid, the toilet until pink, the shower, the outside shower, and the washer/icemaker if fitted. Pour a cup into every P-trap and the toilet bowl. Done when every fixture runs solid pink.
Tools: RV antifreeze
Two to three gallons covers most coaches. Do not forget the outside shower and the washer prep lines.
Recommendation
For most owners: antifreeze in the lines. It protects the pump, the traps and the toilet seal that a blow-out can leave wet. Blow-out suits owners with compressors who dislike the taste. Both need the water heater bypassed and drained.
Tools: none
Whichever they pick, the heater bypass and the outside shower are the two steps everyone misses.
Flush the pink out
Set the water heater bypass back to NORMAL first. Fill the fresh tank, run the pump, and open every faucet (hot and cold), the toilet and the showers until the water runs clear with no pink.
Tools: none
Bypass back to normal BEFORE running hot faucets or the element can run dry. Flush until clear. Then sanitize: 1/4 cup of household bleach per 15 gallons of tank, mixed in water, into the fresh tank. Fill, run every faucet until you smell bleach, let it sit 4 hours, drain, and flush with fresh water until the smell is gone.
Fill and test
Fill the fresh tank, run the pump, and open every fixture one at a time until air stops and water runs steady. Check under the coach for leaks at the low-point drains you closed.
Tools: none
Air in the lines is normal at first. Watch the low-point drains. Then sanitize: 1/4 cup of household bleach per 15 gallons of tank, run every faucet until you smell it, sit 4 hours, drain, and flush.
Split lines or fittings
Frozen lines split at fittings and outside runs first. PEX with cinch rings is repairable with a fitting and a crimper.
Tools: PEX fittings, crimper
Cut out the split section, fit a coupling, crimp, pressure-test with the pump before closing up. Check EVERY outside run and low-point drain - they freeze first.
Water heater freeze damage
The heater froze with water in it. The tank, the nipples, or the relief fitting can be split. Do not fire it until inspected.
Tools: flashlight
Inspect the tank exterior, the relief valve, and the fittings for weeping with water in the tank. A split tank means replacement. Split nipples or fittings are replaceable.
Pump freeze damage
The pump froze and cracked its housing or the internal check valve. Symptoms: leaks from the pump body, or it runs and never builds pressure.
Tools: hand tools
Replace the pump or its head assembly. Check the strainer housing too - it cracks first on many models.
Fixture freeze damage
Toilet valves and single-handle fixture valves crack internally. Symptoms: water running with the fixture off, or a steady drip.
Tools: hand tools
Replace the toilet flush valve seal/valve or the fixture cartridge. These are standard parts.