Flexwatt Question

[mattj8501]

I have a home made, three level, 28 qt rack made out of melamine. It's three tubs long. I just recently put in 6 inch flexwatt to replace my old 4 inch because every thing has grown and I planned on using the old 4 inch for a smaller rack. There is 13 feet of heat tape all together, and I have my probe taped to the heat tape on the middle shelf, as I did the last time. But I'm noticing I have to set my thermostat higher than I did with the 4 inch and the temperatures vary more from shelf to shelf. The middle tub in the center of the rack stays the hottest. I have my thermostat (VE-200) set to 95 and its giving me temperatures between 88-93 degrees depending on tub location as for the 4 inch kept me in between 89-91 with the thermostat set to 92. I use a space heater on a Ranco thermostat that keeps the room at 79-80 degrees all day. Anyone have any idea on how to get a more constant temp? Everything is doing great but its just frustrating me. I am also using paper towels for substrate.

[WmHrbst]

Is the t-stat probe fully covered? Any pics of the rack would help as well.

[mattj8501]

Like fully covered with tape? It's not placed under the flexwatt. Just taped on top of it. I can take pics tomorrow.

[WmHrbst]

You want the probe taped down securely but don't cover the entire probe with the tape, it will give you false readings. Depending on when you switched the tape I would also give everything a day or so to fully adjust. I'll try to help you more once I see a picture

[mattj8501]

I switched it like a week ago. I'll take a pic of how it is tomorrow when I get home. Working third shift tonight.

[mattj8501]

This is how it's taped. Middle shelf. I'm between too tubs.

[kitedemon]

Don't use foil tape on the probe it can have negative effects. (not account for the tape as much as the room) You might try a couple of things. First check all the flexwatt connections make sure they are all perfect. The second is to place a strip of foil tape down on the flexwatt where the probe will be. Then place the probe on top of it and use eletrical tape to secure it. This should help even the heat where the probe is rather than isolate it.

[mattj8501]

Why would I put the foil tape under the electrical tape? I don't really understand what you mean

[WmHrbst]

As I mentioned before don't cover the probe completely with the tape, doing so will cause unstable temps in the tubs because the tape acts as a blanket. The temp inside the tape and probe is going to be hotter than the flexwatt that is exposed to the room.

[kitedemon]

All carbon heat elements have hot and cool spots. Aluminum will in a small area conduct heat to the probe and in a small space help to even out the flexwatt some.


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