Truma Hot Water System - Problem

FraLyn · Veteran Member

Truma Hot Water System - Problem

KJB · Guru

Maybe faulty electric heating element KB

herks · Veteran Member

Isnt there a switch on the unit to swap over from gas to AC?

Treecrest14 · Senior Member

Has it ever worked on 240v? Our 240 switch is in a cupboard, and I only found out about it when investigating the removing of the dust cover off the outlet.

FraLyn · Veteran Member

Thank you all for your responses.
KJB - Not sure if it is the electric heating element or thermostat, Will need to check further.
Herks - No switch as such to swap from gas to AC other than to select temperatures of 65c or 75c.
Treecrest14 - yes it has worked on AC in the past - but stopped working recently.
Will be back in Sydney during this week, so will investigate further.
Frank

Treecrest14 · Senior Member

Frank

There has to be a 240v power lead somewhere near the HW system - they are not hard wired without some sort of switch or circuit breaker. As it has worked in the past, my guess it has either been unplugged or switched off.

FraLyn · Veteran Member

Hi Treecrest14

Have checked the AC powerpoint and it is on and working properly. Checked with another appliance.

Tony Bev · Guru

Hello FraLyn

I am not an electrician and my model may not be the same as yours

You mention that you do not have a switch to switch from gas to 240 VAC

Ours is a model Truma B 14
In the picture below
The lower switch is for the gas operation with three positions 70 degrees, off, or 60 degrees
The upper switch is for the 240 volt, which can be either on, or off

My model owners manual does say
Quote
The electrical heating element is fitted with an excess temperature cut-out.
In event of a fault, switch off at the control panel, wait 5 minutes, then switch on again.
Unquote

When the fault is rectified, can you please let us all know what went wrong, as your problem may happen to someone else

robol · Veteran Member

Hi Frank, my Truma hws is gas/electric and the ac electric side is switched on at the power point where the 3pin plug is fitted.

Cheers Rob.

FraLyn · Veteran Member

Thanks for your replies Tony Bev and Robol
Tony - in our MH there is only the bottom switch as per your photo.
The AC powerpoint is located under the bed and the plug is inserted in fully and is switched on. I tested the powerpoint and it has power to it -tested using another appliance.
I did manage to get through to a recommended Dometic repairer in Sydney who advised me that the AC to HWS comes on as soon as the MH is plugged into the external AC source.
Will do some further testing to ensure the AC gets to the HWS internally once I remove the cover of the HWS. Will keep you all posted as to the results.
Cheers
Frank

250downunder · Member

Hi Frank,
Most Truma hot water systems have a small 10 amp. ceramic slow blow fuse fitted on the control PCB. They are known to fail for no apparent reason. I have recently had one fail on a Truma system that was less than 9 months old. The unit has worked without further problems following replacement of the fuse. The replacement must be identical to the original - they have an identifying colour stripe code on them similar to a resistor. [they are available on Ebay].

FraLyn · Veteran Member

Hi Ray

There is no mention at all in the handbook about this fuse - only the one for gas operation.

Have booked the MH for repair job tomorrow - will inform results.

Thanks

Frank

Two Strays · Senior Member

Hi All

We have just returned home after 3 mths on the road. As GNs do, discussions regarding HWS where forthcoming. The Truma HWS was high on the list. One motorhome owner has had to replace his three times because of split seams, resulting in a wet MH. Apparently the manufacturers know the problem and are endeavoring to fix it. The problem is expansion (when hot) and contraction (when cold) of the water cylinder. The problem is reduced if the temperature constant.

A heavier gauge metal is being tested as well as a better pressure reduction mechanism .

Owners of such a HWS should maintain a close eye open for leaks.

Happy caravanning

FraLyn · Veteran Member

Hi All
An update on our Truma HWS.
As per my initial problem - HWS not working on AC.
Took the MH to Alternate Gas Refrigeration at Arndell Park - near Blacktown in NSW, who checked the plug for shorts or leakages - none found.
No fuse for AC within the HWS, only one for gas on the PCB. HWS comes on when connected to AC.
Connected AC to the MH and checked if any Amps was being drawn and noted around 4Amps being drawn using a AMP clamp meter, indicating the HWS electric heater element was functioning normally. The system was now functioning normally without any changes being made to the HWS.
So either the AC plug was not fully plugged in or after disconnecting the gas and the AC the system reset itself - a mystery to me - at the same time looking a bit foolish.
So not sure what resolved the issue.
Thank you for your responses.

Frank

aussie_paul · Guru

FraLyn wrote:
Hi All
An update on our Truma HWS.
As per my initial problem - HWS not working on AC.
Took the MH to Alternate Gas Refrigeration at Arndell Park - near Blacktown in NSW, who checked the plug for shorts or leakages - none found.
No fuse for AC within the HWS, only one for gas on the PCB. HWS comes on when connected to AC.
Connected AC to the MH and checked if any Amps was being drawn and noted around 4Amps being drawn using a AMP clamp meter, indicating the HWS electric heater element was functioning normally. The system was now functioning normally without any changes being made to the HWS.
So either the AC plug was not fully plugged in or after disconnecting the gas and the AC the system reset itself - a mystery to me - at the same time looking a bit foolish.
So not sure what resolved the issue.
Thank you for your responses.

Frank

lol, not the only one to experience that Frank!!! biggrin

Aussie Paul. smile