Topaz Truma Ultrastore water heater

I have a strange problem on the rotary temperature control for the water heater that goes from 30 - 70 degrees.

Water heater works on electric when I understand from reading the A/S operating manual that the temperature is fixed at 70 degrees and recommended to be used from time to time to kill off any bacteria in tank.

However when trying to rotate the rotary control the gas solenoid operates and get green light but unable to turn the rotary temperature control any more than between 30 - 40 degrees almost as though it requires another action such as pressing whilst turning at same time but tried all methods and will not budge.

Anyone come across this or have any ideas ?

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That is not a daft question, but this might be a daft response!  On my Topaz the there are effectively two controls in one. The outer ring is the on/off control and the centre piece, which can be rotated separately, is the temp, setting.
I note that in your photograph the on/off position using the outer ring coincides with the stated 30/40 degree position. Are you only turning the outer ring to achieve required temp. ?
Keith

When you were trying to adjust the inner rotary control, had you set the outer ring to the on (flame) position.  In the photo, it's set to the off position. 
Not sure if that would make any difference . . .

Edit: Keith beat me to it!

Many Thanks keith and Roger for suggestion and replies I had tried that but just to be sure have been and retried it and even with gas mode selected with outer ring the inner will not rotate beyond 40 and sits happy at 35.

Can I ask on yours does the inner ring only rotate when the outer is selected to gas and or does it rotate across the range when gas outer ring is either position on or off.

When the outer ring is turned to gas with the gas bottle and valves all open I can hear the gas control solenoid click and i get a green light indicating the burner has lite. 

Just seem to lack adjustment and point to a problem in the control switch.

Thanks

The outer ring moves only a few degrees between Off and On.
The inner rotates through the full temperature range as marked,   irrespective of whether the outer is On or Off.
Keith

Thanks Keith for confirming that,

Carried out a test today measured water temperature from tap in a bowl reading 26.6 Degrees not surprising with the current heat wave giving air temperature of nearly 30 degrees. 

Turned on gas supply and selected gas operation on switch, left water heater to run for 30 mins and measured temperature out of tap in a bowl now getting 57 degrees.

Continued to leave heater on for a total of am 11/2 hours and measured water temperature again it was now reading 65 degrees. 

So would appear that temperature control has jammed or failed in maximum despite indication showing only 40 degrees.

As I am aware of this and it comes through mixer taps the temperature can be moderated by adding cold so not too much of a problem.

It does look like the rotary switch has mechanically failed somehow I will take it out and have a look but not immediately as need to us the van shortly.

When I resolve the issue will report back as it may help others who experience a similar problem.


Thanks Zeberdy

Thanks for the feedback.  Pleased that you have at least found a workable solution.
Keith