water heaters

[Pete-B]

Evening all,

 

I read somewhere that a guy had to have the electric elements replaced on his Truma water heater and was told by Truma that you should always bring the water up to temperature using gas and electric, then switch over to leckie. The theory is, if you use just electric to initially heat up, this is what, over time, burns the elements out

 

I wonder if he same theory applies to the whale system?

[Don636]

There is a Whale water heater on my van and it has been used almost extensively on electric only over the last seven years and it has never had any problems of any sort.

[Derek Uzzell]

With a Truma combination gas/230V air/water heating appliance, it might make some sort of sense to ‘pre-heat’ using gas (or gas + 230V) the appliance’s central heat exchanger in which the 230V elements are housed before switching the heater over to 230V-only operation. But Truma’s operating instructions make no mention of this ‘gas first’ sequence being advisable and/or that starting heating on 230V from ‘cold’ might shorten the lifespan of the electric elements.

 

Whale’s gas/230V space or water heating systems appear to be based on discrete units (rather than everything being jammed into a single appliance) so - even if Truma’s suggestion to pre-heat mght have merit for a Truma ‘combi’ - there’s no persuasive reason to think this might also be best practice for the Whale appliances.

 

https://www.whalepumps.com/rv/product-application.aspx?Category_ID=10003&FriendlyID=Space-Heating

 

https://www.whalepumps.com/rv/product-application.aspx?Category_ID=10002&FriendlyID=Water-Heating

 

[colin]

I wonder which Truma they have, as the Combi instructions say that in water heating only 240v is automatically selected and 'mixed mode' cannot be used.

[teflon2]

Pete-B - 2021-09-30 5:10 PM

 

Evening all,

 

I read somewhere that a guy had to have the electric elements replaced on his Truma water heater and was told by Truma that you should always bring the water up to temperature using gas and electric, then switch over to leckie. The theory is, if you use just electric to initially heat up, this is what, over time, burns the elements out

 

I wonder if he same theory applies to the whale system?

I've had several units with Trauma gas/electric heaters and the only time I used both was when using the shower as it makes for fast reheating

[Derek Uzzell]

colin - 2021-09-30 6:05 PM

 

I wonder which Truma they have, as the Combi instructions say that in water heating only 240v is automatically selected and 'mixed mode' cannot be used.

 

There are only two types of Truma ‘combination’ space/water heater that can have 230V air heating - the earlier C6002EH appliance and current “Combi (E)” models. Both of these have ‘rod’ 230V heating elements that can heat the appliance’s central heat-exchanger core that, in turn, transfers heat to water and/or air.

 

A C6002EH or Combi (E) can be operated on gas, on 230V, or in ‘mixed-mode’ (230V + gas). A C6002EH’s maximum air-heating output is 7800W in mixed-mode (6000W/gas + 1800W/230V) but - as the 1st image attached below shows - mixed-mode is not possible just for water heating (Summer mode) and, if the mixed-mode setting is selected on the heater’s control-panel, 230V will be the sole power source.

 

Combi (E) appliances differ in that, when in mixed-mode, their maximum heat output does not exceed the appliance’s maximum heat output on gas. The various heating modes are described on the 2nd image attached below. As this says, in mixed-mode 230V operation is preferred, and my understanding is that the 230V heating elements will be switched on first and gas operation be ‘added’ later only if the room temperature demands it. (My 2005 Hobby motorhome had a C6002EH heater, but I only used 230V for water heating and never used mixed mode. However, I THINK a C6002EH in mixed-mode also turned on the 230V elements first and followed up with gas if necessary.)

 

What this boils down to is that (as I believe you are highlighting) in order to pre-heat the heat-exchanger prior to the 230V elements coming into play, the heater must be put into gas-mode to begin with, then put into electric-mode or mixed-mode.

 

Whether or not what Truma advised would significantly extend the life of the 230V elements, the reality is that users of these appliances cannot be expected to further complicate the already complex operating principles by pre-heating the appliance on gas and only selecting 230V operation after the heat-exchanger and its electric elements have been warmed up.

 

This 2020 forum thread may be of interest

 

https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Truma-Combi-6E-electrical-heating-problem/56256/