Truma Combi E blown 240v 10a fuse

[MikeD]

Well I hope I have found out why the 240v heating is inoperative on the Truma heating.

A blown 10amp fuse buried behind a panel on the boiler, that was jammed in by the converter between the side of the van and the bed mounts/base.

I had to dismantle the entire bed, ducting, gas and water supplies. Release the boiler from its floor mountings to allow space for the removal of the electrical cover on the boiler.

Fuse ordered and hopefully when fitted will bring the boiler to work again. 4.5hours so far.

Photo's are not great, apologies for that but I thought you may be interested.

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All you can see when the bed has been dismantled.

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Bed stored in the front of the van

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The only way to isolate the gas was on the tank. Valve underneath this cover.

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Boiler on its side to allow access

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Upper electrical panel with the 12v fuse which you can replace by just sliding off the outer/small cover.

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You need to remove the larger cover (two screws at top and clipped on the lower edge. You need to swing it out a far way to clear the boiler parts to release this cover.
The fuse for 240v operation is 10amp slow acting, interrupting capacity H type and cost just 31p.

 

[jezport]

There should be in inside gas shut off valve or a manifold with separate gas valves for each appliance

 

[MikeD]

I thought that as well but we have only one valve and that shuts off cooker and fridge.

When it goes back together I am considering fitting another gas valve for the boiler and making the fuse "remote". So it is more accessible.

This all stems back to the rubbish habitation check I had in February. Only found it was not working when we got to Spain.

 

[jdk62]

Make sure it is a time delay fuse (£3-£4 for a pack from Maplins )

 

[Bart]

Make sure it is a time delay fuse (£3-£4 for a pack from Maplins )

Never heard of time delay fuses before, what's the difference??

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[jdk62]

Never heard of time delay fuses before, what's the difference??

They withstand excess current slightly slower than conventional fuses. If you put in a standard fuse they will trip regularly when there is no real fault

 

[jezport]

The fuse should have a T before the ampage. For example T10A

 

[MikeD]

The fuse should have a T before the ampage. For example T10A

Yes - device fuse: 10amp (slow acting) T 10A) for 12v

230v : 10 amp - slow acting, interrupting capacity "H"

 

[daveandsan]

Have you found out what caused the fuse to blow?

 

[MikeD]

Have you found out what caused the fuse to blow?

Not really but suspect it was caused at the crappy "Hab" check we had this year. We had the van checked out locally and looking back it was a mistake.

It was only a few days later we were on the ferry to Spain and only found out then the 240v heating was inoperative. The 12v fuse for the TV was blown as well.

Don't know how they occurred but were signed off as ok at the "hab" check.

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[Rover Prufski]

Thanks for the excellent photos Mike D. I would never have found the lower fuse otherwise!

For info, without any power attached to the heater, I removed the top fuse (10A) which was fine, so replaced it - but the screen still was stuck on clock/spanner. However, after I'd removed the lower fuse (which was also 10A & fine) and put it back in, the control panel started working properly again .
I guess removing the lower fuse had the effect of completely removing any residual capacitance/power and reset everything...

 

[charliesgrandad]

I know this is an old thread, but found it while looking to see what's wrong with my 6e combi not working on electric and came across this , so with a lot less hassle than the OP had I got the cover off and checked the lower 240v fuse and it is fine so I assume it will be now over to the experts as it is probably the elements that have gone

 

[GeoffnDee]

charliesgrandad have you checked the red overheating protection button does not need resetting ?

 

[charliesgrandad]

I will have a look tomorrow, but if it is working on gas would it need resetting?

 

[GeoffnDee]

yes, it is a mechanical overheating switch covering 230v heating which can be activated if the 12v power supply is interrupted during operation, it is on the left side with the top cover of the electronics/fuses removed. It is red and you press to reset it. (according to the Truma operating manual for the Combi E )

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[charliesgrandad]

Can't remember seeing it when I had all the covers off but will look in morning , and searching online people have said and posted photos of it being on the right side at the top

 

[GeoffnDee]

It looks like it can be seen on the photos at the start of this thread,. on the left in one photo (as in Truma manual) and the right in the other photo taken from the opposite side of the unit.

 

[dunnah01]

Can't remember seeing it when I had all the covers off but will look in morning , and searching online people have said and posted photos of it being on the right side at the top

The switch is top left

 

[charliesgrandad]

Ah , Thanks Dunnah01 I vaguely remember that when I had the full cover off, and a couple of minutes ago found online someone pushing a match through the main cover, and presumably that was to hit the button you have highlighted, there seem to be quite a few combis in photos with a red button to the right of the panel that can be seen with just the clip-on cover removed

 

[charliesgrandad]

Thanks for the suggestions, pressed reset this morning then turned on hot water on electric and went back in a couple of hours and it was still cold water , looks like will have to have new elements if I can find anyone within a" couple of days" in my backwater that does Truma repairs

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[Roger20]

The fuse for 240v operation is 10amp slow acting, interrupting capacity H type and cost just 31p.

Thought I would get some spare fuses just in case - but nothing is straightforward!

MikeD is correct that the fuse type he quotes for the lower panel electronic is slow acting interrupting capacity H. My manual (dated 2017) says that the upper panel fuse is also a slow acting 5 x 20mm (T10A) but makes no mention of the interrupting capacity. However when I remove it the marking shows T10A L 250V which seems to be interrupting capacity type L.

This site shows more about fuse markings https://www.swe-check.com.au/pages/learn_fuse_markings.php - low and high breaking capacity ratings typically range from 35A to 10kA. What little research I read shows that the distinction between low and high breaking capacity might influence whether or not the fuse blows with potential damage if wrong.

Marking	Fuse Breaking Capacity
H	High Breaking Capacity
L	Low Breaking Capacity

So it seems there is possibly/probably a distinction between the upper and lower fuses. The ones I bought are 10kA so seemingly OK for the lower panel but not necessarily for the upper fuse.

To make matters more confusing, those who own newer vans should be aware that the page below from the 2019 instructions shows that the requirement is now for fast acting F10A fuses. Perhaps the electronics have changed in which case identifying exactly what boiler you have is important. In my case the label on the boiler matches my instructions.

I have asked Truma UK for their observations.

 

[GeoffnDee]

Thanks for the suggestions, pressed reset this morning then turned on hot water on electric and went back in a couple of hours and it was still cold water , looks like will have to have new elements if I can find anyone within a" couple of days" in my backwater that does Truma repairs

charliesgrandad Has it been confirmed that 230v is getting to the combi ? it would be worth getting this checked before thinking about replacing the elements in case they are not the cause of the problem. .

 

[charliesgrandad]

Thanks GeoffnDee,
There is a fused spur supplying the boiler about 18 inches away from boiler , I removed the face plate and checked that there was 230v on both in and out terminals