Dometic RM 7655L - mains OK, gas OK, 12V = freezer only!

[gdhgdh]

This is an interesting one; I'm still learning about our new (to us) van - 2006 vintage Dethleffs.

The RM7665L works well on gas and 230V - fridge around 3C and freezer around -15C - perfect!

The story is strange on 12V, tho' - whether the engine is running or not, the freezer will still work fine, but the fridge itself has no cooling at all.

The starting temp for both fridge + freezer (I have digital thermometers in each) was 18C. I unplugged the mains, and manually turned the fridge dial to 12V (and max cooling) and the ammeter immediately deflected into the green by about 7A (I have 4 x 100W panels, and today has been a scorcher!).

When I came back over 2 hrs later, the freezer had reached -5C, but the fridge was still at 18C (yep the fridge light did come on).

It's the same story if I leave the engine running - freezer works fine, but not the fridge. Is there anything simple I can check, or is this expected behaviour?

 

[Happy Jim]

You probably just need to leave it longer, all the cooling area is bunched up at the top hence the freezer freezes first, once there is no ambient heat left it will then (eventually) start to suck heat out of the lower coils (fridge)

 

[Richard n Ann]

Our fridge (not freezer) performance dropped off with the dried out paste..

Our 3 way fridge saga

My story just might help someone with 3 way fridge trouble so here goes; We've had our motorhome 3 years now and the fridge was always ok even in Spain's high ambient temperatures, until suddenly about a year ago we were in Spain, temperatures were the usual high twenties and I noticed the...

www.motorhomefun.co.uk

 

[Lenny HB]

As Richard says paste probably dried out. In theory it can't happen there is only one cooling circuit, the freezer only freezes as it has the same amount of cooling as the fridge in 20% of the area.

 

[gdhgdh]

The write-up about the paste is super interesting and I'll definitely keep that in mind if the general performance starts to slip. It doesn't sound like that's the issue here since running on either mains or gas works perfectly.

In the meantime I'll try again and just be more patient =)

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[Lenny HB]

The 12v element is smaller than the mains one, on our 8505 fridge freezer the mains element is 250 watts the 12v one 190 watts.

 

[gdhgdh]

Mm, does anyone have recommendations of someone who can service at least the gas portion of these things in the north west? Happy to travel 50+ miles radius from Wigan. I don't have any knowledge of the local caravan centres - whether they'll just say 'it's bust, mate - new one is 2 grand'

Should the hot tank in the fridge actually get too hot to touch? On gas, the tank gets 'very warm' but I can still hold my hand on it. The zigzag pipes are 'warm'. The freezer will now only drop to about -2C, and there's no frost on the evap pipe in the fridge (alas, the fix is not as simple as 'replace the heat putty').

I'm trying on 240V at the moment - it's drawing about 220W, but I'm going to say it's safe money the fridge hasn't been serviced for a looong time. When it comes to gas, I'd rather pay someone who knows what they're doing!

From the pics, I'm kinda impressed it works at all.