low flow heater problems

[Dan Mauser]

Hello!

I want to buy one hot box to serve both my carpet cleaner that has .25 to 2 gpm and pressure washing of 4-5 gpm. I spoke with 3 or 4 manufacturers, a couple of whom recommended I talk to a place that retails their hot boxes.

The retailer said there would be a few problems with a 350kbtu hot box serving such low flow rates compared to a 65kbtu heater. He said there would be a large fluctuation in outlet water temp (120-210F), and that this wouldn't happen at higher flow rates. But I don't understand how that can be.

Here's how I understand a hot box works:

1. Water temp 50, so hot box fires up, heat until 210 then shuts off burner

2. I spray hot water slowly with my carpet cleaner pump. Water temp gradually drops below thermostat off temperature (~190?) and burner comes on again and the cycle repeats.

Seems to me a high flow system would have more temp fluctuation.

Are there adjustable temperature settings for having the thermostat kick on and also to kick off? Like I could set it for 210 off and 190 on?

Guide me to deeper knowledge, please
Dan

 

[jschessler]

flow rate

To repy to your answer, you cannot convert a pressure washer to a carpet cleaning machine or specialy a carpet cleaning machine to a pressure washer. The carpet cleaning machine operates at 450psi when doing rugs time the flow of water you are looking at about 1000 cleaning units with a flow of 2 gpm, this is typicaly the best was to go belly up in the powerwashing industry if that is all your machine can do. Pressure washing machines typically have 5.2 gpm at 3000 psi which in cleaning units is close to 16,000 units. the higher the flow the higher the btu's need to be in most cases, but if you have to do both you have to start with a pressure washer that is technically adjustable to a carpet washing machine with a large enough blower ,4.5 and up, to recover the water from the carpet. If you got the money start with the prochem 805, otherwise buy a pressure washer.