Anybody ever link 2 heater controllers

[Simon_M]

If two controllers are wired in series, then both have to be “on” for the heater to be powered. if either controller is above the set temperature then it will go “off”. The tank will be maintained at the lowest set point.

If one of the controllers stays permanently ”on” regardless of the temperature reached or set, then the second one maintains the tank at its set point. Providing the highest set point is not too high, the tank is saved.

 

[mizimmer90]

If two controllers are wired in series, then both have to be “on” for the heater to be powered. if either controller is above the set temperature then it will go “off”. The tank will be maintained at the lowest set point.

If one of the controllers stays permanently ”on” regardless of the temperature reached or set, then the second one maintains the tank at its set point. Providing the highest set point is not too high, the tank is saved.

This makes sense *if and only if* the heaters are only placed on the last controller. But OP clarified that each controller will have heaters.

 

[ShakeyGizzard]

This makes sense *if and only if* the heaters are only placed on the last controller. But OP clarified that each controller will have heaters.

 

[mizimmer90]

this is about a stuck on controller, that's all I need covered, each controller can have 2 heaters as redundancy , this will cover any stuck on ( as in cook your aquarium) heater

"Each controller can have 2 heaters as redundancy"

 

[BeanAnimal]

You don’t need two controllers or to replace them yearly. Buy a single ranco and use it to control two parallel undersized heaters. Use the heater’s built in thermostat as the fail safe. If you want more redundancy use two parallel controllers with a single undersized heater each or two 1/4 sizes heaters each. Again, use the on board thermostats as fail-safes, not controls. Series controllers just creates a higher probability of single point failure.

 

[ShakeyGizzard]

"Each controller can have 2 heaters as redundancy"

possible, but #1 is to protect against stuck on #2

 

[mizimmer90]

possible, but #1 is to protect against stuck on #2

Best of luck!

 

[BeanAnimal]

If two controllers are wired in series, then both have to be “on” for the heater to be powered. if either controller is above the set temperature then it will go “off”. The tank will be maintained at the lowest set point.

If one of the controllers stays permanently ”on” regardless of the temperature reached or set, then the second one maintains the tank at its set point. Providing the highest set point is not too high, the tank is saved.

And you spent twice the money to create a single point failure chain.

 

[ShakeyGizzard]

And you spent twice the money to create a single point failure chain.

been running this for 13 years with fresh water, only need to replace one controller per year since I rotate # 1 to number 2, lets hear your better idea

 

[slythy]

I use an apex and have it watch over my inkbird. I think its fairly standard practice.

 

[BeanAnimal]

been running this for 13 years with fresh water, only need to replace one controller per year since I rotate # 1 to number 2, lets hear your better idea

I already posted my better idea with a fairly detailed explanation.

If you like your single point of failure and lack of true redundancy and buying a new controller every year, then that is your prerogative. Do whatever makes you happy even if there are better ways.

 

[KStatefan]

What type of controller are you using that needs replaced annually?

 

[ShakeyGizzard]

What type of controller are you using that needs replaced annually?

I use titanium heaters, the controller is ink bird, the controller is what normally will fail first in the set up due to repeatedly cycling on and off. You don't have to replace the controller, you can wait until it fails. This is an economical way to have protection from a controller that fails stuck on.

 

[BeanAnimal]

I use titanium heaters, the controller is ink bird, the controller is what normally will fail first in the set up due to repeatedly cycling on and off. You don't have to replace the controller, you can wait until it fails. This is an economical way to have protection from a controller that fails stuck on.

Again - there is no need to buy new controllers every year (if you buy quality) and you would be better served with TWO properly sized (~50% capacity) heaters and running your controllers in parallel. You remove the single point failure and rapid overheat protection. Want super safe and super redundant, then 2 controllers and 4 1/4 sized heaters. Or 3 controllers and 3 1/3 sized heaters, etc.

What is a quality controller? Example, A RANCO ETC controller has a power relay with a rated mechanical life of 1x10^7 cycles (full load) and an electrical rated life of 1x10^5 (full load)

In the case of a RANCO ETC - the full (120V) load rating is 16A - so 1920 Watts. If you are running a 1500W heater, that is 78% of the rated load. However, any SANE person would split that into two 750W or three 500W heaters for real world redundancy reasons. Seeing that you already have two controllers, then running them in parallel makes FAR more sense for both up-time and fail-safe as well as being gentle on their associated controllers.

We can argue about the difference between electrical and mechanical failure and which comes first... but unless you are hammering the relay with short cycles (seconds or tenths of a second apart) mechanical failure is not going to happen. Likewise if you are running a load that is some percentage less than the rated output, then the electrical life is extremely unlikely to be met either. Also note that these numbers are Not MTBF numbers and rather minimum expected operating life, most (even at full load) will last many many times longer.

Any way you slice this - your "way" simply makes little sense if true redundancy or fail-safe operation are actually considered against real world probability.

 

[ShakeyGizzard]

Again - there is no need to buy new controllers every year (if you buy quality) and you would be better served with TWO properly sized (~50% capacity) heaters and running your controllers in parallel. You remove the single point failure and rapid overheat protection. Want super safe and super redundant, then 2 controllers and 4 1/4 sized heaters. Or 3 controllers and 3 1/3 sized heaters, etc.

What is a quality controller? Example, A RANCO ETC controller has a power relay with a rated mechanical life of 1x10^7 cycles (full load) and an electrical rated life of 1x10^5 (full load)

In the case of a RANCO ETC - the full (120V) load rating is 16A - so 1920 Watts. If you are running a 1500W heater, that is 78% of the rated load. However, any SANE person would split that into two 750W or three 500W heaters for real world redundancy reasons. Seeing that you already have two controllers, then running them in parallel makes FAR more sense for both up-time and fail-safe as well as being gentle on their associated controllers.

We can argue about the difference between electrical and mechanical failure and which comes first... but unless you are hammering the relay with short cycles (sends or tenths of a second apart) mechanical failure is not going to happen. Likewise if you are running a load that is some percentage less than the rated output, then the electrical life is extremely unlikely to be met either. Also note that these numbers are Not MTBF numbers and rather minimum expected operating life, most (even at full load) will last many many times longer.

Any way you slice this - your "way" simply makes little sense if true redundancy or fail-safe operation are actually considered against real world probability.

you don't have to buy new controllers every year, but the whole purpose of this is stop over heat completely. Not to possibly have smaller heaters stuck on and heating the aquarium. Also any SANE person would not say "mechanical failure is not going to happen" . All electrical components can fail at anytime , so yes basically every system has a single point failure some where. It can be the APEX, it can be the wall receptacle, it can be the ranco, the inkbird, the heater itself, the cables, etc.

 

[Jamie814]

Seems like you are trying to way over engineer this.
I run two 20 amp gfci circuits for my system split half/half, each with one apex eb832 power bar with 1 Jager heater setup on each. Heaters built-in temp control set about a degree higher than apex as backup. Heater outlet fallback set to ON. If head unit fails then heater controls itself. Been nearly 10 years with this method and never an issue....

 

[Simon_M]

I have been trying to use two controllers (sort of).

I have been using one controller and one heater for 18 months:

1. D-D Dual Temperature Controller;
2. D-D Titanium Heater 650W.

The Heater fits in my Sump and has the added benefit (to me) of grounding the tank. I have twice had the Heater fail (burn out/disconnect) - replaced under warranty twice.

I have been trying two controllers and one heater in the last week:

1. D-D Dual Temperature Controller;
2. Eheim ThermoControl e400 Electronic Heater (includes a controller).

The Eheim Heater is in my Sump horizontally in a high flow area - it's quite long so can't really be placed upright in the Sump as the instruction would like. The Heater is rated for up to 0.5m depth.

With the Eheim set to 25.5 C and the Dual Temperature Controller set to 27 C, the Eheim can control the temperature at around the set point and the controller doesn't switch. The Eheim has either a red or green light showing that the controller doesn't switch.

I noticed that the power drawn by the heater averages 200W when active. It is switching between 400 W and being off every few minutes. Compared to the 650W Heater it isn't always on. I used a 200W heater set high as a standby when the D-D Heater failed - it is (just about) sufficient for my tank.

With the Eheim set at 27C and the the Dual Temperature Controller set to 25.5 C, the D-D controller can control the temperature at around the set point and the Eheim doesn't switch. The Eheim has either a red light showing it is powered or the light is off (unpowered). The 400W heater does provide 400W when the controller has it powered.

The Eheim and D-D does provide me with a benefit - if either controller failed in the "on" condition then the tank wouldn't get too hot. As previously noted there is a double SPOF as there is twice the equipment. For me, failing to heat is preferable to over heating.

Unfortunately the Eheim isn't earthed so my tank isn't grounded - I do get zapped frequently so that is a bit of a disadvantage (for me). Otherwise it does work OK-ish as a double controller setup. As an example I don't have two D-D controllers.

The D-D provides very good regulation of the tank temperature as an active controller. I was a little surprised that the Eheim didn't stay on until the set point when it was the active controller and the regulation wasn't quite so good. Perhaps the arrangement caused the cycling and/or converted it to a 200W heater as the set point was reached?

 

[ShakeyGizzard]

Seems like you are trying to way over engineer this.
I run two 20 amp gfci circuits for my system split half/half, each with one apex eb832 power bar with 1 Jager heater setup on each. Heaters built-in temp control set about a degree higher than apex as backup. Heater outlet fallback set to ON. If head unit fails then heater controls itself. Been nearly 10 years with this method and never an issue....

possibly so, but I like the titanium heaters, only use a heater with built in thermostat to heat my water bin when mixing salt . not everybody can afford an APEX or similar, you can get 2 ITC-306a inkbirds for $70 on amazon (today). I run 100 and 200 w heaters

 

[cdnco2004]

You don’t need two controllers or to replace them yearly. Buy a single ranco and use it to control two parallel undersized heaters. Use the heater’s built in thermostat as the fail safe. If you want more redundancy use two parallel controllers with a single undersized heater each or two 1/4 sizes heaters each. Again, use the on board thermostats as fail-safes, not controls. Series controllers just creates a higher probability of single point failure.

This is what I do. 1 controller but each heater has its own thermostat. On the big tanks I use controllers that power 2 heaters that are half the power needed for the full tank. Only real risk is if controller breaks and keeps the heaters in the OFF setting. My light systems also report temperature so I can get alerted if the temp drops due to a controller failure. I have never had both a controller and a heater fail at the same time.

 

[BeanAnimal]

you don't have to buy new controllers every year, but the whole purpose of this is stop over heat completely. Not to possibly have smaller heaters stuck on and heating the aquarium. Also any SANE person would not say "mechanical failure is not going to happen" . All electrical components can fail at anytime , so yes basically every system has a single point failure some where. It can be the APEX, it can be the wall receptacle, it can be the ranco, the inkbird, the heater itself, the cables, etc.

Sure mechanical failure can happen, but it is about the probability of it happening based on the hardware chosen and the topology in which it is utilized.

The same holds true with single point of failure. It is about the probability. You make redundant high failure items and eliminate single point failures with redundant paths, etc.

If nobody is going to change your mind or (in your eyes) make a valid point, why did you post and why are you engaged in the conversation? You are free to setup your heaters any way you wish and purchase as many controllers as you wish. In my opinion you are wasting money and under utilizing equipment, that given the same count (cost) could be better employed.