Bottom heater

Can someone clarify how the GHL operates with a bottom heater?

According to the manual the bottom heater takes precedence over the heater. The heater is switched on only when the bottom heating alone is inadequate.

This feature is potentially useful to me, as I have a heatpump that is the prefered heating method, with titanium heating elements as a backup. So I could set the heatpump as the "bottom heater" and the titanium heaters as the "heater".

But I am unclear exactly when/how the GHL determines the bottom heater can't cope and kicks in the main heater. Is there a built in time lag? Or does it wait for the temperature to drop even further? What is the logic process the GHL follows before turning on the main heater?

Thanks,

Keith

there are 2 temperature levels: one activates the heater, if the temp. falls below the second level the bottom heater will be switched on. Both have a overlapping hysteresis.

Quote:

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Originally Posted by Matthias

there are 2 temperature levels: one activates the heater, if the temp. falls below the second level the bottom heater will be switched on. Both have a overlapping hysteresis.

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Thanks Matthias, could you confirm my understanding using the following example?

My "nominal value" is 26C, with a hysteresis of 0.4C. So if the bottom heater would turn on at 25.8C at what temperature would the heater activate - 25.6C ?

Regards,

Keith

With a hysteresis of 0.4 C, the heater would be activated at temp<25.8 C (botton heater then already switched on). At temp>26.2 C, the botton heater will be switched off (heater then already switched off).

Quote:

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Originally Posted by Carolin

With a hysteresis of 0.4 C, the heater would be activated at temp<25.8 C (botton heater then already switched on). At temp>26.2 C, the botton heater will be switched off (heater then already switched off).

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Sorry, please bear with me, I just want to make sure I am getting this right.

So as temperatures fall the bottom heater is activated at 26C, the heater at 25.8C? And as temperatures start to increase the heater will go off at 26C and at 26.2C the bottom heater will also go off? Correct?

Keith

Yes, correct.

Quote:

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Originally Posted by Carolin

Yes, correct.

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Thank you for your patience!

Regards,

Keith

I've only got one heater in my tank...

Should I have the Profilux use that as "bottom heater" so that it comes on soonest and begins heating, or should I have it as just the "normal heater"

Thanks

Normal heater. Bottom heater function is designed for bottom heaters :)