I've got a old carpet cleaner that I sometimes use to clean carpets in
rentals. I don't clean enough carpets to justify large expenditures for
modern equipment.

My old rig is ok .... but has no heat at all. Frequently the rentals I
service don't have power/water on to obtain hot water from the
faucet .... so I thought about building a low-power solution heater.

If I take a 1000 watt water heater element and install it in a 2"
diameter galvanized pipe, I can somewhat control the temperature with a
water heater thermostat strapped to the pipe (set to 160F). Problem is,
I need a (cheap) serial sensor to measure pressure and close the circuit
only when the line has pressure (a no pressure reading means out-of-
water).

What cheap water pressure sensor/actuator would work for this?

Jus' Joe wrote:
I've got a old carpet cleaner that I sometimes use to clean carpets in
rentals. I don't clean enough carpets to justify large expenditures for
modern equipment.

My old rig is ok .... but has no heat at all. Frequently the rentals I
service don't have power/water on to obtain hot water from the
faucet .... so I thought about building a low-power solution heater.

If I take a 1000 watt water heater element and install it in a 2"
diameter galvanized pipe, I can somewhat control the temperature with a
water heater thermostat strapped to the pipe (set to 160F). Problem is,
I need a (cheap) serial sensor to measure pressure and close the circuit
only when the line has pressure (a no pressure reading means out-of-
water).

What cheap water pressure sensor/actuator would work for this?

1000 watts isn't going to do much with flowing water.

Greg

Jus' Joe:

The idea of putting a water heater element in a piece of 2 inch galvanized pipe doesn't sound crazy. But, somehow making a waterproof 240 volt electrical connection inside that water filled pipe sounds very very scary to me.

If I were you, I would just buy an electric immersion heater, like this:



and heat your water right at the job site in a metal pail.

1 Canadian gallon of water weighs 10 pounds, so 5 Cdn gallons weighs 50 pounds.
Assuming the water starts off cold, say at 40 deg. F, we want to raise it's temperature by 120 degrees F to 160 deg. F.
So 50 pounds of water times 120 degrees F = 6000 BTU of heat is needed
1 Watt = 3.413 BTU per hour
so a 1500 watt immersion heater would provide 5120 BTU in one hour,
so it would take about 70 minutes for a 1500 watt heater to heat up the water assuming 100 percent efficiency. You won't get 100 percent efficiency because some of that heat is going to be lost to the air surrounding the water container.

But, if you have two metal pails and two immersion heaters (plugged into different outlets obviously), then each heater could heat up 25 pounds of water in 35 minutes, and even allowing for heat loss from the metal pail to the surrounding air, the water should still be easily hot enough to use for shampooing a carpet after half an hour.

Alternatively, if you can't find immersion water heaters on sale locally, you can buy square pails like these in various sizes:



They're called "square pails" and I've seen hard ice cream come in these kinds of pails. I expect any place that serves ice cream in the summer would probably give their empty pails to you free.

Drill two 1 1/2 inch diameter holes in a square pail with a hole saw, and use PL Premium construction adhesive to glue an engine block heater in each hole. You can liberate engine block heaters from your local auto wrecker for $1 each, and you can check them for continuity to make sure they work before you buy them.

For a near purely resistive circuit, Watts = volts times amps
but amps = volts / resistance, so

Watts = (volts times volts)/resistance or 14,400 divided by ohms or 14,400/ohms

You don't want to trip a breaker, so you want block heaters that draw 750 watts or less, so that you can plug both block heater cords for each pail into a duplex receptacle on a separate circuit in each house.

To get block heaters that draw less than 750 watts, you need block heaters whose measured resistance is 19 ohms or more.

Then just fill your pails with cold water when you get to the job site, and by the time you spray down your preclean enzyme and give it 15 minutes to work, your water will be warm enough to put in your extractor. It might not be 160 deg. F, but you don't need that kind of heat. Even 120 deg. F is hot enough for your soap solution.

Seriously man, submerging a pair of 240 volt 30 amp electrical connections in water is an easy way to make yourself extinct. There's only one of you, and everyone on this web site wants to keep the one of you we've got for as long as possible. The block heater water pails will give you a practical, cheap, effective and SAFE alternative to heat water for your extractor. With your idea of the water heater element in the iron pipe, everytime you touch that pipe you're going to be thinking: "Touching this pipe very well might be the last thing I do on this good Earth." With the square pails, you can always unplug the heaters before pouring the water into your solution tank, and that makes it safe because you take electricity out of the equation before you pick up the pail to pour the water into your extractor.

If you do opt for the water heater element in the iron pipe, AT LEAST make a point of only touching that pipe with one hand. Keep the other hand firmly in a back pocket. That way, if there's a short, and there's 240 volts in that pipe, the path the electricity takes will be through your arm, through your torso and down to the floor (or wet carpet) through one of your legs. The beauty of that kind of electrical shock is that the electricity does not pass through your heart, and that's absolutely critical. Keep one hand in your back pocket and only touch that pipe with the other hand or the other to ensure there's no path by which electricity can reach ground by passing through your heart. That way you live to tell us all about it and carry on the good fight.