Juwel Vision 260 Heater Problems

[GaryArgent]

I have recently set up a new VIsion 260 and I am seeing some inconsistencies with the heater temperature.
 
When the heater is in the tank the indicated temperature on the heater is about 5 degrees C higher than the water temperature measured in the tank.  For example when the heater is set at 30 the water temp is 25.  I've measured the water temp at both ends of the tank (no different) with two different thermometers (which both give the same reading).
 
I've removed the heater from the tank and set it up in a bucket where the heater is now inclined (it is vertical in the tank).  The heater still seems to read high but not by quite as much - now 30 on the heater gives a water temperature of 27.
 
Can anyone offer any suggestions?  Do I have a faulty heater or is this sort of thing common?  I had the heater inlined at 45 degrees in my old tank but that is not possible in the Juwel as the heater is fitted inside the filter case.
 
Thanks in advance for any help!
 
Gary

 

[fluttermoth]

It is quite common for the scale on heaters to be out by a few degrees. Go by the readings on the thermometer
 
Oh, to the forum, btw!

 

[Blubble37]

trust your thermometer, heaters are rarely very accurate

 

[GaryArgent]

Thank your both for your quick responses - I'll stick with the thermometer temperature from now on!
 
Happy new year,
 
Gary

 

[eaglesaquarium]

One of the reasons is that vertically, as the water heats up it rises past the thermostat and shuts off the heater sooner than it should... Heaters are far more efficient placed on a 45degree incline or horizontally. But this can be remedied by turning the temp higher on the heater to adjust for this.