Flexwatt heating tape

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Old 11-10-18, 11:03 AM
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Flexwatt heating tape

THis low wattage heating tape is about 12 inches wide and 2 ft long.
It has plastic insulators on the connector clips.You can buy any length and install your own connectors if you want but I bought a pre made piece ready to go. Its made by Calorique.Its used often to warm reptile enclosures and other things.
I need a way to make sure my water heater doesnt ice up when I am gone for a week at a time so I put this 2 ft strip under the 1 inch fiberglass cover on my electric water heater.I used duct tape fasten it on the metal surface of the water heater.It will ONLY be used when the breaker is OFF. I shut off the breaker when I am gone . DO you see any problem with this. I will have it on a commercial grade metal Intermatic timer to go on 4 times a day for about an hour.
 
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Old 11-10-18, 11:24 AM
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It remains unknown whether the piece of Flexwatt you bought can provde enough heat even if it was on 24/7.

You will need to do that homework, which will probably involve a lot of trial and error.

Use as some of the measuring techniques a thermometer under the water heater blanket on the other side of the heater.

Alternative project: Get a line voltage electric heating thermostat good for 30 amps or 7 KW, provides a safety margin controlling the water heater's own elements. Get a 30 amp 240 volt double pole (for 240 volts) single throw (ordinary on-off) switch.

Install a junction box at the water heater. Run the water heater branch circuit through, connecting up the thermostat (placed under the water heater blanket near the bottom) and using the 30 amp switch as a bypass. (No changes to water heater wiring under its hatches.) With the switch "on" the water heater operates normally and the behavior of the thermostat is moot, With the switch "off" the water heater's own elements will come on via the blanket thermostat when the temperature drops to critical levels and will switch off when the temperature rises to a safe level although the heater built in thermostats are unsatisfied and the tank contents will be far from hot.

Leave the water heater breaker on.
 

Last edited by AllanJ; 11-10-18 at 11:46 AM.
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Old 11-10-18, 05:31 PM
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it only needs to provide a few degrees under the fiberglass.
I think it might work if I put it on 7 hours a day.But if anyone has tried it post here what happened..
 
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Old 11-10-18, 06:14 PM
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Why not leave it on low when your gone?
 
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Old 11-10-18, 08:20 PM
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You would be placing the heat on the shell of the tank, not the inside vessel that actually holds the water. The insulation between the two is going to slow.or.stop the heat reaching the water.
 
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Old 11-11-18, 07:22 AM
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the thermostat idea is good. But....do you mean stuff the whole unit under the insulation or is there a probe that comes with it?? even so its going to read
the outer temp not the water temp. so what makes it turn off?
 

Last edited by stan3992; 11-11-18 at 09:30 AM.
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Old 11-11-18, 09:30 AM
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So long as there is no way the water heater tank can drain dry or be siphoned dry, it is okay to leave the water heater running with the cold water inlet shut off.
 
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Old 11-11-18, 12:09 PM
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regarding that thing about not having heat elements in a dry tank... why is that so bad??
would they just stay on for days???
 
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Old 11-11-18, 12:17 PM
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A heating element running in a tank with no water will burn out almost immediately.
 
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Old 11-11-18, 02:21 PM
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I am looking for a simple but rugged line thermostat online and reading the reviews. There are Many. And many of those have LOUSY reviews.
Breaking down after a few months etc. What 240v models are NOT going to be junk? Or is that impossible to find in china/junkmade America?
 
 

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