I completely agree that this works too but is obviously more costly. I think the dimmer would work as a back up especially if you room temps stay pretty decent like mine (72-80)
10-08-2011, 12:38 AM
kitedemon
The problem is, the dimmer limits power from the t-stat. Exactly like you describe. It works perfectly in stable room temps why use a t-stat at all. Stable room temps don't change and a dimmer is all that is needed. Lets say you do not have stable room temps they vary and the use of a t-stat is needed. So you set you dimmer to provide a max temp of 100? say 75% power to the pad. The problem comes in when the room temps drops the t-stat is trying to over come the room temps but the dimmer is restricting the top end temp and at 78º room temp it delivers 100º but at 68 is is maxing out at 90º so the t-stat stays on all the time and the enclosure fails to get over 88 or 90 as the enclosure takes some temps. With tubs that lose heat quickly this can be exaggerated more than my example.
A second T-stat checks temps and as the room temp drops its probe responds the same way. It requires less intervention on the keeper. The part that makes me really question this idea is if it is set in a cool environment and the t-stat fails in a warm one the dimmers maxed out temp could be quite high, too high even. Especially with flexwatt that can get very hot.
10-08-2011, 10:26 AM
Billy305
Good point. I was assuming it would make the t stat stay on.buy not sure how much more. The herpstat says it has feature that will turn it off if it.fails but I guess a backup is still good
10-08-2011, 03:12 PM
aboutsnakes
nice work mate!
10-08-2011, 07:13 PM
kitedemon
Herpstast shut down if the probe fails but the unit can also fail and has a good chance of failure wide open. I have had one of 15 probes fail the unit continued to run full blast. I would always recommend a failsafe, a dimmer if you have stability and a second t-stat if you don't. The units don't fail often but pulled off probes is far more common. Failsafes protect against accidents too.
10-11-2011, 07:59 PM
Billy305
@kitedemon. Thanks again for the input. I just ordered a herpstat for my rack and I think I'm going to order one of those hydrofarms you were talking about in one of these other posts as a on/off back up. What do you think?
I think I am also going to buy a few extra hydrofarms for ambient heat bulb temps for my 40 gallon breeder when the house starts to get a little cooler in the winter. Would you use a back up for the UTH and lamp as well?
