Cold air from Truma 4e

[Chris CM]

My van has a Truma 4e fitted with the old style twin dial controls. I understand that if it was fitted with the newer digital display control I would be able to blow cold (unheated) air out through the vents. As my 4e could be upgraded to the digital controller it seems to me that it may be possible to add a switch? to enable just the fan to operate and blow unheated air out. Has anyone done this hack or know of any information about it?

Thanks

 

[Lenny HB]

Yes you can do it with the CP Plus controller but it's a waste of time. I've tried it as it only circulates air within the van you have to have the fan running full blast and it then draws 6 amps and hardly has any effect on the temperature in the van. Never use that function now even if it's over 35 deg, doesn't do enough to make any odds.

Much better reasons for upgrading to the CP Plus are, far better temperature & fan control, once up the temp you wouldn't even know it was on just ticks over at a very low fan speed keeping the van warm & the timer is useful.

 

[Chris CM]

Yes, I do like the look of the CP Plus but the cost plus the hassle of finding somewhere to mount it put me off. Maybe I’ll just stick to my desk fan

 

[motorhomer]

I have a CP Plus, and like it overall. So we can circulate cold air. But as Lenny said it isn't very cold! And if you have hot water in the boiler the "cold" air is rather warm! So we don't use this facility much.
But there is one thing we do use it for. After a shower the shower room has hot damp air in it, and our van has a vent but no opening window. So in warm weather we often put the cold air blowing through to blow air through the shower room, which is quite useful.

 

[Lenny HB]

I fitted one in my last van, I just opened up the hole where the existing controller was and it plugged into the same data cable just had to wire it to a permanent 12V supply.

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[Chris CM]

But there is one thing we do use it for. After a shower the shower room has hot damp air in it, and our van has a vent but no opening window. So in warm weather we often put the cold air blowing through to blow air through the shower room, which is quite useful.

Now that’s a thought! Same as mine!

 

[Chris CM]

I fitted one in my last van, I just opened up the hole where the existing controller was and it plugged into the same data cable just had to wire it to a permanent 12V supply.

I thought it was a bit more complex than that and had to be wired back to the boiler/heater unit. Did yours originally have the 2 round dials? Mine looks like this.

 

[Lenny HB]

On the one I changed had just one dial, all our motorhomes the heating has been gas only.
It does have to be wired back to the boiler but the wires are already there it uses the same cable with RG11 connectors, so you don't have to change it

 

[Tykatem]

I thought it was a bit more complex than that and had to be wired back to the boiler/heater unit. Did yours originally have the 2 round dials? Mine looks like this.

If your Truma is post 2013 (can be recognised as being all black) then all you'll need to do is replace the control panel with the CP plus.

truma.com/web/downloadcenter/files/truma-cp-plus-installation-operating-de-en-fr-it.pdf

Prior to that if it's the older grey type you'll also need to replace the PCB on the boiler

Nachrüstung des Bedienteils Truma CP Plus – Was muss ich wissen? | Truma Serviceblog

serviceblog.truma.com

The link below shows how easy it is to retro install a CP plus panel.

https://womo.blog/2017/01/25/so-wird-die-truma-zur-komfort-heizung/

Pete

 

[Chris CM]

Tykatem, thanks for the link, looks like his was gas only. However, I’ve just whipped mine out to check on the connections, the two dials are linked together with an RJ11 cable, then an RJ11 cable from the energy selector dial disappears down the ducting. So as Lenny HB says looks like I’d just have to find a permanent 12v feed (I take it this is for the clock as my system only works when the van 12v is switched on on the main panel?)

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