Flexwatt Connecting & Herpstat Question

[Sarin]

I am going to be purchasing a Herpstat II along with 15 Feet of 4" Flexwatt.

I plan on building a 10 shelf rack with belly heat, each shelf will have 1 or 2 ft of flexwatt depending on what tubs will be placed on each shelf. Also, the flexwatt on each shelf will be wired to its own extension cord.

I plan on hooking all shelves to a couple high quality power bars and then connecting the final power bar to the Herpstat II (since most power bars only hold 6-8 devices that I am aware of, and I need 10). Is this safe to do?

Each output in the Herpstat II can heat up to 700 watts, 15 Feet of 4" Flexwatt is only about 120 Watts.

Thanks.

[flynn]

...Is this safe to do?...

That should be fine

[chapskis1]

I'm no electrical genius, but I just think you need to make sure that all of the flexwatt that you are hooking up to each input of the herpstat is the same length.

I think you said you would be using 1 and 2 ft pieces of flexwatt -- so just make sure that all of the 1 ft. pieces are controlled with one input, and all of the 2 ft. are controlled with the other. I think otherwise you will get two different temps -- I could be completely wrong, but maybe something to look into a little closer.

Later,

George

[Sarin]

I tested it out yesterday and they seem to be spot on with at most a 1 degree difference. But I didn not have it plugged in for long. I will re-test it tomorrow and leave it plugged in all day and see what I get.

I really hope I don't need 2 thermostats for this rack. It has already cost me a fortune.

[flynn]

The Herpstat II is two thermostats. Two input sensors, two outputs. You really shouldn’t have any problems. Chapskis1 raises a good point though, that your flexwatt needs to be the same length for each output of the herpstat (in other words stick to either 1 foot or 2 foot lengths on either output, dont mix).

Maybe some trial and error with probe placement, but what your trying to achieve will work with the equipment you have.

[Sarin]

I only have the Herpstat. I really hope this isn't the case. I'll be pretty upset. I have 5 shelves of 12" and 4 shelves of 24", the probe is in the middle on a 24" strip.

[Sarin]

Hey, I just had an idea. If this is the case, maybe I could cut the 24" in half and just wire them separately but they'd be basically the same. I'll be adding 4 more wires to hook up but at least I won't have to go buy another herpstat? Opinions?

I am so not good at these things!

[flynn]

Ahh I see. One option would be to run the 12" on a rheostat. The setup would be something like...

Herpstat -> Power bar -> 24"
.............-> rheostat -> power bar -> 12"


I have done this in the past with the same size flexwatts (12" and 24") and it worked well, however the ambient temperature was very consistent. The theory behind this is that the 24" strips will require more power to get and stay at temp then the 12". So if you didnt have the rheo, your 12" would run to hot. With the inline rheo you can dim the power to the 12" strip to come down to the right temp.

I would highly suggest testing this for as long as you can stand to be sure your setup works. I had mine going for about 3 weeks before I trusted the setup (I hate rheos, but the price was right until I found a decent price on a second herpstat).

[Sarin]

I have a few of those hanging around so I will just do that. Phew. I will test it out tomorrow and see how it works out.

Thanks for the help.

[flynn]

To append my previous post....IMHO a rheo should never be 100% trusted, they are a band-aid solution. Like a splint on a broken leg instead of a cast. I would start thinking about a long term solution. Save up for another thermostat, or somehow become flexible in the lengths of your flexwatt.

It depends on how your rack is built, but if you have 12" and 24" strips, would 16" work? Could you change your 12" strips for 24"? If the tubs are only 12" wide for example, the exposed flexwatt is just heating the air (assuming wider shelves). Personally I would rather have exposed and unused flexwatt (that essentially does nothing other than waste power) than a rheostat.

Just some food for thought.