Using hot water with a pressure washer? Bad idea?

[Dan Friedrichs]

I've read conflicting reports regarding this - is it a super bad idea to run hot water (like, 120F water from my residential water heater) through a homeowner-grade pressure washer? I understand the pump may get hotter, but does hot water clean better, potentially justifying the increased risk to the pump?

[Mike Henderson]

My pressure washer has a specification for the max temp of the water. I don't remember but 120 may be acceptable, or maybe just a bit over the spec.

I have a CAT triplex pump on my pressure washer.

Mike

[Kevin Bourque]

The cheap-o plastic impeller and other cheap-o parts may be damaged by very hot water.

[Biff Johnson]

I don't think it would be a problem. Have you ever felt the pump on a pressure washer when it's running, especially a homeowner-grade cheapie unit? They get plenty hot by themselves! Your poor water heater will be working overtime though.

[Brian Ashton]

I would say hotter water can absorb more of the cleaning chemical or wetting agent you choose to use compared to cold water but hotter water doesn't necessarily clean better. I.e. does 140F water clean better then 100F water - don't think there's much if any evidence on that... Steam cleaning does clean a great deal better but that's a whole different scenario that's not available to you with a pressure washer. Sp if you need more of a solvent to clean something then hotter water may be a benefit. If all you want to do is blast off crud with high pressure then probable not.

[Brian Elfert]

I worked at a fairgrounds in my youth. My very first day on the job involved working with a steam cleaner to clean an animal barn (All the chunky stuff was long gone.). We also used the steam cleaner in some other buildings. The steam cleaner was dangerous and I heard rumors about at least one death related to it. The steam cleaner burned diesel and a lot of it. A 55 gallon drum might make it two days. We had a pallet with four fuel drums on it.

I worked at the fairgrounds for seven years during the summer and switched to grass cutting after a year. Some time during my tenure they ditched the steam cleaner and went with a pressure washer that had a built-in water heater. The hot water pressure washer worked as well as the steam cleaner for the most part. They had a nifty device for cleaning concrete that worked way faster than the steam cleaner. I assume they wouldn't have spent the extra fuel to heat water if it didn't make a difference. I don't believe they used any chemicals with the pressure washer, but not really sure.

I couldn't imagine running a pressure washer for very long from a home water heater. The water heater on that hot water pressure washer was pretty big and was designed to heat water continuously.

[Jason Roehl]

I couldn't imagine running a pressure washer for very long from a home water heater. The water heater on that hot water pressure washer was pretty big and was designed to heat water continuously.

Right--most pressure washers fall in the 3-5 GPM range, so a typical 40 gal water heater would be drained of its original water in 8-13 minutes if you hooked the supply hose directly to it. That's not much time to get much done. Plus, once you were halfway through the original water, the water temp would be halfway between the starting temp and the supply temp--if those numbers were 120ºF and 50ºF, respectively, in about 5 minutes, you'd be using 85ºF water (recovery on water heaters is not very good, so the burner's contribution would be just about negligible).

[Greg Portland]

I've read conflicting reports regarding this - is it a super bad idea to run hot water (like, 120F water from my residential water heater) through a homeowner-grade pressure washer? I understand the pump may get hotter, but does hot water clean better, potentially justifying the increased risk to the pump?
The pump on a cold water unit uses the water to cool the pump. Running hot water through it would likely overheat the pump causing premature failure. I can almost etch concrete with my cold water unit (rotary nozzle)... why do you think you need to run yours with hot water?

[Jim Becker]

Necro Thread is from 2013. It was resurrected by a spammer who was removed.