The forecast says twenty eight degrees Thursday night. Your rig is sitting where it always sits, with water in the pump, water in the coil and a charged hose on the reel.
Nothing happens Thursday. Nothing happens Friday either, because the damage a freeze does is quiet and you do not find it until the next time you pull the trigger and the gauge does not move.
So here is how to winterize a pressure washer, in the order you actually do it. Four parts: what a freeze breaks and why, the sequence itself, what the chemicals and the rig need separately, and what to check on the first cold morning before you drive out.
Water expands and your pump is in the way
Water picks up volume as it freezes. That is the whole mechanism, and everything expensive follows from it.
In a pump, the water sitting in the head has nowhere to go, so it pushes outward on whatever is holding it. You get a cracked housing, a split manifold, or valves that seat badly from then on. In a coil on a hot water machine you get the same pressure inside tubing that was never built to take it from the inside. In a hose you get a blown braid, sometimes right away and sometimes three weeks later at full pressure, which is worse. An unloader that froze once rarely comes back quite right, and it will cost you a week of hunting for a pressure problem you cannot see.
None of that announces itself. You find it in March, standing in a parking lot you quoted in February, with a property manager watching you load a machine back onto the trailer. She does not know what an unloader is. She knows you said Tuesday and it is now a week from Tuesday and the lot is still dirty.
How to winterize a pressure washer, in the order you do it
We have written this up three times over the years. The winter maintenance checklist is the list to work down, our winter maintenance guidance covers the method, and what we tell people about long term storage goes furthest on the engine. They do not agree on everything. Where they differ, both answers are below, because either one works and which you pick usually comes down to what is already on your shelf.
The machine, before it sits
- Change the pump oil to the manufacturer’s specification before anything goes into storage.
- Look at the seals, packings and plungers. Wear you can see now is a rebuild you schedule instead of a breakdown you get handed.
- Put antifreeze through the pump. This is the step the next section is about, and it is the one that saves the expensive part.
- Work the unloader and confirm it moves smoothly rather than sticking.
- Check the pressure gauge against something you trust.
- On a hot water machine, drain and winterize the coil completely, then look at the burner nozzle, the electrodes and the air band.
- Drain every hose, pressure and garden, all the way. Then look at them for exposed braid and damaged crimps while they are in your hands anyway.
- Clean and inspect the nozzles and the surface cleaner, and replace any trigger gun that leaks or trickles.
The engine, if the machine is going away until spring
- Fuel. Top the tank off and add a stabilizer, which keeps condensation out and keeps the fuel from turning to varnish. Or go the other way, drain the tank and run the engine until it is out of gas, which our storage page calls the better practice. Both are in our guidance. The stabilizer route is the one most contractors do.
- Fog the engine. Pull the spark plug wires and spray WD-40 into the carburetor while you turn the engine over. If it is going away for the whole winter, pull the plugs too and spray WD-40 into the cylinders, or use Marvel Mystery oil, then turn it over a few times to coat the walls.
- Change the engine oil, the oil filter and the fuel filter. Skip the oil change and the sludge settles to the bottom of the pan and solidifies over four months, which is a problem you inherit in March.
- Check the battery voltage, clean the terminals, then disconnect it so it does not trickle itself flat while you are not looking.
That is the whole thing. Twelve steps, and more than half of them are looking rather than doing.
The antifreeze step, and what comes back out in spring
Step three is the one that saves the pump, so it is worth doing properly rather than quickly.
AR Pump Saver is what we carry for it. Its page states that it “allows cold weather storage by protecting the pump from freeze damage.” It also says the product “lubricates the pump seals which extends the pump life,” and that one bottle “has enough product for 4-5 pump treatments.” That middle claim is the one contractors skip past. You are not only displacing water. You are leaving something behind that keeps the seals from drying out while the machine sits.
For a bigger machine the method in our winter maintenance guidance is to put antifreeze in the float tank, start the machine and push the water out ahead of it. Pull the tip off the wand, put the wand back into the tank, and let it recirculate for a couple of minutes while you squeeze the trigger on and off. The on and off is the part people miss. That is what drives fluid into the unloader bypass line, which is the circuit that otherwise sits full of water all winter. Put a second bucket on the chemical line while you are there.
Catch what comes out in a clean five gallon jug and you will use the same fluid all winter. Check its freeze point before you trust it.
One honest note, since we are merging three of our own articles here. Our long term storage page describes doing this with automotive antifreeze and says units have come through five winters that way with nothing worse than a popped pump inlet valve. Plenty of contractors do it. AR Pump Saver is what we sell and what we would put through a pump, because it lubricates the seals on the way through and automotive antifreeze does not.
What comes back out in spring is just fluid. Run clean water through until it does. On a hot water machine, keep the burner off until you have flow established. Firing a burner into a line that is not moving water is how a bad morning becomes a dangerous one.
The spring list is short: fresh fuel, new spark plugs, and a shot of WD-40 into the carburetor intake if it does not want to start. Clean the battery connections and grease them before you reconnect. Descale the coils, and if you run a burner, Red Devil Soot Remover goes in the diesel or kerosene.
The chemicals and the rig have their own winter
The machine is not the only thing on the trailer that a freeze gets to.
On the soft wash side, flush the lines, look at the diaphragms, valves and fittings, and drain or protect the proportioners and injectors. Sodium hypochlorite needs to be stored properly and anything past its life needs to go. That is a better conversation to have in November than in April, when you are mixing for a roof.
Then the rig itself. Secure the tanks, reels and anything mounted. Walk the plumbing looking for low spots that hold water, because that is where a freeze finds you after you thought you were done. Lubricate the reels and swivels. Pull the PPE out and replace what is damaged while you are thinking about it.
If you have a shop, the bay door is worth twenty minutes too. Weather stripping, a door kept lubricated and serviced, Styrofoam panels, a heater at the threshold, and one door open at a time so you are not running a wind tunnel through the building. Two of our pages say to swap the steel rollers out, one for magnum rollers and one for magnesium, so take whichever your door supplier stocks.
The first cold morning
Winterizing is not only for the machine you are putting away. Most of you are still working.
Before you pull out on a morning below freezing, put your hand on things. Turn the pump over by hand with the plugs disconnected before you ask an engine to do it, because if something is frozen solid you want to find that out gently. If the machine did freeze, it wants around half a day somewhere warm, and it wants you to watch it afterward, because freeze damage shows up late as often as it shows up immediately.
On the road, a machine freezes at a higher outside temperature than you would guess, since low ground runs colder than the number on the dash. If you are running a tank, keep the water moving rather than letting it sit.
And keep a spare unloader on the shelf. Not because yours is going to fail, but because the one week you need it is the week nobody has one.
What this is worth
Price the two outcomes against each other before you decide this can wait until the weekend.
On one side: a bottle of antifreeze, twenty minutes at the end of a Thursday, and a list you work down once. On the other: a pump, or a coil, or a hose and an unloader, plus the labor to fit them and the days you are not earning while you wait. Add the jobs you move and the one customer who does not call back because you moved theirs twice. Most contractors have a number for that from a year they would rather not talk about.
So do the twelve steps. Put AR Pump Saver through the pump properly, drain the hoses all the way, and keep enough parts on the shelf that a cold morning is an inconvenience instead of a week. If you are replacing something that already went, pumps and plumbing, pump parts and hose are where that lives.
We have been family owned since 1973, and the people answering the phone have put a machine away for the winter and gotten it wrong at least once.
Call 1-800-433-2113 and we will go through your setup before the first hard freeze.
