Turn off heaters if on for more than x minutes

[Japatstic]

Sorry if this has been asked before. Is there a way to only allow my heaters to stay on for x amount of minutes per hour/hours, regardless of what the probe is reporting? Just want a fail-safe in case the probe fails or it somehow gets pulled out of the water.

[zombie]

It can be done, but I prefer a different approach myself. What I do is have my heaters alternate under normal conditions, both run if one can't keep up, and when there is a loss of comms or obviously low temp only one runs. Both heaters have internal thermostats set 2 degrees above normal tank temp as an additional layer of protection. Below is an example

Heater1
Fallback ON
If Temp < 78.0 Then ON
If Time 00:00 to 11:59 Then OFF
If Temp < 77.8 Then ON
If Temp > 78.1 Then OFF

Heater 2
Fallback OFF
If Temp < 78.0 Then ON
If Time 12:00 to 23:59 Then OFF
If Temp < 77.8 Then ON
If Temp > 78.1 Then OFF
If Temp < 75.0 Then OFF

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[Japatstic]

Thanks, I’ll take a look at this later. It’s day 1 of Apex ownership so to say I’m green is an understatement! My heaters have no internal thermostat so above code won’t be quite right, should have mentioned that in the first post... They are both 600w Schego’s.

[rkpetersen]

Sorry if this has been asked before. Is there a way to only allow my heaters to stay on for x amount of minutes per hour/hours, regardless of what the probe is reporting? Just want a fail-safe in case the probe fails or it somehow gets pulled out of the water.

For those two situations you mention, you can add a line to your heater code:

If Temp < 71.0 Then OFF

This will shut the heater off if the temp probe fails (generally will give a very low number), or if it drops below ambient air temp (assuming your house is kept at less than 71; will not work in summer, but then it will read higher as well and thereby keep the heater off anyway.)

[Japatstic]

Thanks, will add that in for protection. Still out of curiosity, is there no way to code a maximum time that outlet can be on?

[zombie]

Thanks, will add that in for protection. Still out of curiosity, is there no way to code a maximum time that outlet can be on?

There is but the approach is not as simple as just entering a maximum time. There are multiple ways to do it.

1. If maximum time is reached, latch the outlet to manual OFF

2. If maximum time is reached, shut the outlet off for a defined amount of time and then allow it to try again.

3. Allow a "duty cycle" using OSC that only allows it to run X minutes ON and Y minutes OFF.

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[Japatstic]

I’d be interested in how number 2 is implemented when you have time.

[zombie]

I’d be interested in how number 2 is implemented when you have time.

This is 15 min max then minimum 5 minute cooldown

HeaterTime
Set OFF
If Output HeaterName = ON Then ON
Defer 015:00 Then ON
Min Time 005:00 Then ON

Heater
(Existing code)
If Output HeaterTime = ON Then OFF

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[Japatstic]

Excellent, thank you.

[Sevitz5]

It can be done, but I prefer a different approach myself. What I do is have my heaters alternate under normal conditions, both run if one can't keep up, and when there is a loss of comms or obviously low temp only one runs. Both heaters have internal thermostats set 2 degrees above normal tank temp as an additional layer of protection. Below is an example

Heater1
Fallback ON
If Temp < 78.0 Then ON
If Time 00:00 to 11:59 Then OFF
If Temp < 77.8 Then ON
If Temp > 78.1 Then OFF

Heater 2
Fallback OFF
If Temp < 78.0 Then ON
If Time 12:00 to 23:59 Then OFF
If Temp < 77.8 Then ON
If Temp > 78.1 Then OFF
If Temp < 75.0 Then OFF

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Is there a reason you don’t have:
If Temp < 75.0 Then Off on Heater #1? Just curious

[zombie]

Is there a reason you don’t have:
If Temp < 75.0 Then Off on Heater #1? Just curious

Because in the event that the temp probe fails or the energy bar goes into fallback, I want to limit the rate at which the heat can increase but I still want the tank heated. This allows a very slow rise in temp to whatever the heater thermostat is set to or the equilibrium temp of the heater (in my case set to 81 but equilibrium temp of one heater only is about 80).

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[Sevitz5]

Makes sense, thanks