Dimmer as backup to Thermostat?

[td30]

I have ordered my Herpstat but I do not have the cash to order a 2nd thermostat as a backup. This is my idea so please tell me what you think...

1. I plug my UTH into my Dimmer.
2. Set the dimmer level slightly higher than it needs to be to
achieve say 95 deg.
3. Plug this into the thermostat that is set to 92 deg.

With the Thermostat at full output, it should be able to achieve the target temp (92) while at the same it will be capped at 95 deg by dimmer. This would also solve the problem of the in tank temp probe getting water spilled on it or otherwise being cooled and the temp running wild.

Am I making sense to anyone but myself? What am I missing?

[ChrisBowsman]

It would not work that way. Each device is going to limit the current (or voltage, depending upon how it works) that whatever is plugged into it receives.

If used together, the dimmer will be limiting the amount of electricity that the thermostat gets, and that is not what you want.

[ChrisBowsman]

Additionally, a thermostat isn't an incredibly complex circuit, but most circuits are designed to operate at a certain level, and putting the dimmer in front is gonna change that.

Considering that dimmers affect the lifetime of a lightbulb, I've gotta think that it's going to have some affect on something like a thermostat.

[td30]

It would not work that way. Each device is going to limit the current (or voltage, depending upon how it works) that whatever is plugged into it receives.

If used together, the dimmer will be limiting the amount of electricity that the thermostat gets, and that is not what you want.

I guess I just don't get it...its late and I am tired. Isn't the Dimmer after the Thermostat? So the dimmer would of course limit the current that the UTH receives, but how would it limit the supply of current comming into the dimmer via the thermostat?

[ChrisBowsman]

I'm sorry... it's too early here

I thought you had the dimmer before the thermostat (in respect to the wall ). Let me kick it around for a minute. I have to go to the dentist in a little while, so I'll ponder it while I'm there

My initial thought is still that two power control devices plugged in together could be problematic, but I could be wrong.

BTW, cool name for your normal I watch A LOT of Pokemon thanks to my 2 & 5 yr olds.

[ChrisBowsman]

Ok, I know it's only been a few minutes, but the more I think about it, it *should* work.

Do you have a multimeter? If I were trying something like this, I'd really want to test it before trying it with a snake. BTW, a multimeter would be a great investment. I realized my rheostat was faulty last night with a 30 second test with the meter rather than having to adjust it, wait for the temps to stabalize, test the temp again, adjust it, etc....

[td30]

BTW, cool name for your normal I watch A LOT of Pokemon thanks to my 2 & 5 yr olds.

Thanks, My daughter and I are huge pokemon fans and we named our snakes after them...Ekans is another snake pokemon (spelled "Snake" backwords )

Ok, I know it's only been a few minutes, but the more I think about it, it *should* work.

Do you have a multimeter? If I were trying something like this, I'd really want to test it before trying it with a snake. BTW, a multimeter would be a great investment. I realized my rheostat was faulty last night with a 30 second test with the meter rather than having to adjust it, wait for the temps to stabalize, test the temp again, adjust it, etc....

Great idea. How did exactly did you preform this test? I have a multimeter.

[lord jackel]

No it won't work that way you think it will. Think of the dimmer in terms of percentages...if you turn the dimmer down half way then it is only allowing half the power to get through.

(as an example we will use degrees)...say your thermostat is putting out 100 degrees this gets to the dimmer you have set at anything less then full (since the dimmer is power management not temp management) will decrease this 100 degrees down some percentage. If you increase the temp to say 110 the dimmer will still decrease the temp getting to the tub so in essence you aren't creating a safety you are having to increase the thermostat higher than necessary to compensate for what the dimmer is removing.

The only way to do what you want is with 2 thermostats (but the backup one can be a cheaper one...but it must measure the temps independent of the main thermostat otherwise how does it know the temp is too high)

Hope this helps

[td30]

No it won't work that way you think it will. Think of the dimmer in terms of percentages...if you turn the dimmer down half way then it is only allowing half the power to get through.

(as an example we will use degrees)...say your thermostat is putting out 100 degrees this gets to the dimmer you have set at anything less then full (since the dimmer is power management not temp management) will decrease this 100 degrees down some percentage. If you increase the temp to say 110 the dimmer will still decrease the temp getting to the tub so in essence you aren't creating a safety you are having to increase the thermostat higher than necessary to compensate for what the dimmer is removing.

The only way to do what you want is with 2 thermostats (but the backup one can be a cheaper one...but it must measure the temps independent of the main thermostat otherwise how does it know the temp is too high)

Hope this helps

Thanks for the reply, but I am still having trouble wrapping my head around this. Both of these devices (Dimmer and Tstat) are current limiting devices. Yes? No? I agree that the dimmer will decrease the power of whatever is input. And yes, the t-stat will increase power to compensate. Does it do this by reducing resistance? If so then will the t-stat at some point be 100% open as if it were not even there? This is what I an envisioning. The t-stat running at something like 98% open to achieve a temp of 92 deg. If it were to fail completely, then the dimmer would be getting 100% of the power (instead of 98%) as if the t-stat were not even there. In that case, the dimmer would still restrict the power to a safe level. I may just need a really dumbed down explanation.

[Gloryhound]

You can get a cheap on off type T-stat for less than $40.00. Hook it in after the herpstat and have it set to a couple degrees higher than the herpstat. I don't know really what the issue is with just using the Herpstat as I don't know of any backups on the pro racks with 10 - 30 adult tubs using only one Helix! Most of these are designed to detect a fault and completely shut off their outputs. The probes on these are actually micro chips that can even detect if the probe develops a fault!