Dometic RM5310 fridge problem

[blackrose]

From the top of the element to the end of the brown live cable I'm getting a reading of 0.L k ohms. I'm sure I'm not testing it properly.

Edited July 9, 2017 by blackrose

[Tony Brooks]

The mains element will have two wires in it. One probably runs from the thermostat. Take that one off and then connect the meter between the two wires wherever you can. If needs must push a pin through the one that you have not disconnected to get the second connection. You could probably use two pins as long as the fridge was totally disconnected but there might still be a parallel path somewhere on the fridge.

[blackrose]

I've disconnected all the element's mains wires from the top of the fridge but I've no idea how to get the element out of the flue housing.

[blackrose]

I haven't managed to get the element out but I'm going to order a new one from ebay anyway. Does anyone know how I check/remove the thermostat on this fridge? Apparently if the thermostat is faulty and isn't switching the fridge off when required, it soon overheats and burns out the element.

Thanks

Edited July 13, 2017 by blackrose

[WotEver]

37 minutes ago, blackrose said:

Apparently if the thermostat is faulty and isn't switching the fridge off when required, it soon overheats and burns out the element.

Is that correct?  My understanding was that when not on gas the element was permanently 'on'. Perhaps that's only the 12V element. 

[blackrose]

46 minutes ago, WotEver said:

Is that correct?  My understanding was that when not on gas the element was permanently 'on'. Perhaps that's only the 12V element. 

Well the selector switch at the front of the fridge means that only one supply can be on. I'd have thought the fridge would get too hot at the back if it was running on mains or 12v and gas at the same time? What would be the point? 

[WotEver]

3 minutes ago, blackrose said:

Well the selector switch at the front of the fridge means that only one supply can be on. I'd have thought the fridge would get too hot at the back if it was running on mains or 12v and gas at the same time? What would be the point? 

My understanding is that the 12V setting is to allow the fridge to get cool, powered by your car, while you transport your caravan to the site. Remember these fridges were designed for caravans, not boats. Because the heat from the 12V element isn't that great it just stays on permanently to enable the fridge to cool somewhat. Once on site you switch to gas and you're away with a thermostatically controlled fridge. 

I always assumed that the 230V element did the same but I could well be wrong. 

[blackrose]

7 minutes ago, WotEver said:

My understanding is that the 12V setting is to allow the fridge to get cool, powered by your car, while you transport your caravan to the site. Remember these fridges were designed for caravans, not boats. Because the heat from the 12V element isn't that great it just stays on permanently to enable the fridge to cool somewhat. Once on site you switch to gas and you're away with a thermostatically controlled fridge. 

I always assumed that the 230V element did the same but I could well be wrong. 

I don't know. I don't have the 12v element connected, just use it on mains or gas and I'm pretty sure they don't both work at the same time. In fact I know they don't because I always switch off the mains when I run it on gas.

I'm pretty sure the mains element must have a thermostat?

 

Edited July 13, 2017 by blackrose

[WotEver]

4 minutes ago, blackrose said:

I'm pretty sure they don't both work at the same time.

No of course not. As I said in my original reply, when not on gas is the element permanently on?

6 minutes ago, blackrose said:

I'm pretty sure the mains element must have a thermostat?

I simply don't know but I definitely wouldn't assume that it does. 

[blackrose]

16 minutes ago, WotEver said:

No of course not. As I said in my original reply, when not on gas is the element permanently on?

I simply don't know but I definitely wouldn't assume that it does. 

No as I said, it's not permanently on. 

It wasn't an assumption. I read on a supplier's website that before fitting a new element one should check that the thermostat was working properly so as not to overheat and burn it out. The point of today's post was simply to find out how to remove and test the thermostat.

[cudnriach]

RM5310 has a battery in the igniter button.  Insert small flat blade screwdriver into the centre of the button push in slightly and turn 90 deg anti clock to release. Be gentle its soft plastic.  Jet in a fridge is very fine. so several attempts to light often needed.  The Temperature dial has to be pushed in to allow gas to flow until the thermocouple can hold the safety device open.  Quite often makes sense to light the cooker first o check gas operation and bleed out any air inthe pipes.

 

[WotEver]

17 minutes ago, blackrose said:

It wasn't an assumption. I read on a supplier's website that before fitting a new element one should check that the thermostat was working properly so as not to overheat and burn it out. The point of today's post was simply to find out how to remove and test the thermostat.

Fair enough, that answers my original question then

[blackrose]

Just now, cudnriach said:

RM5310 has a battery in the igniter button.  Insert small flat blade screwdriver into the centre of the button push in slightly and turn 90 deg anti clock to release. Be gentle its soft plastic.  Jet in a fridge is very fine. so several attempts to light often needed.  The Temperature dial has to be pushed in to allow gas to flow until the thermocouple can hold the safety device open.  Quite often makes sense to light the cooker first o check gas operation and bleed out any air inthe pipes.

 

Thanks. I don't have a problem lighting the gas - the problem is keeping it lit.

[alan_fincher]

If it is a fairly recent fridge, (which II'm sure I recall it is), then the temperature control does indeed work when running on 230V.

I'm pretty certain even the old ones did, but since I sold the boat with a really old one, I no longer have the manual.

Edited July 13, 2017 by alan_fincher

[cereal tiller]

24 minutes ago, alan_fincher said:

If it is a fairly recent fridge, (which II'm sure I recall it is), then the temperature control does indeed work when running on 230V.

I'm pretty certain even the old ones did, but since I sold the boat with a really old one, I no longer have the manual.

Yes, I have a Modern Dometic RF60 3 way fridge ,the stat operates on 230 Volt and when using Gas.in 12 volt mode the Element is on permanently.

Edited July 13, 2017 by cereal tiller

[mross]

Here's the installation manual http://td.dometicgroup.com/download.php?file=1037

Here's the operation manual https://cdn.dometic.com/assets/15/98/rm53xx-b-aus-01_41598.pdf?att=true

Edited July 14, 2017 by mross

[WotEver]

10 hours ago, cereal tiller said:

Yes, I have a Modern Dometic RF60 3 way fridge ,the stat operates on 230 Volt and when using Gas.in 12 volt mode the Element is on permanently.

Thanks. That's the bit I was unsure about (stat on 230V). 

[blackrose]

I've managed to remove the mains element. I can test it with my other cheapo multimeter but where do I place the probes for a resistance test?

[Tony Brooks]

On the ends of the yellow and brown leads.

If it has burned out expect 1 on the opposite end of the window to normal  numbers or full scale deflection on an analogue meter.

Edited July 15, 2017 by Tony Brooks

[mross]

Agreed, the green/yellow wire is just an earth.

[blackrose]

Ok thanks, I did a resistance test across the two brown wires on my other meter and got an open circuit so the element is indeed toast. I'll report back once I've got a new element and fitted it.

[Tony Brooks]

Whoops - I did not see the other brown lead - not sure now what is what as I have never had one out. I expected just two wires unless one of those brown ones is for 12V but if that is so I would say its dangerous to use the earth as a neutral.

[mross]

How many wires are there?  The photo is blurred.  If you look at fig 14 on page 11 of the INSTALLATION manual, the AC heater is item 11.  You need to measure across the two, brown wires.  The numbers are identified on pages 26 and 27.  The manual is confusing as it covers several models.  

Resistance should be around 320 Ohms according to other forums.

Edited July 16, 2017 by mross

[Tony Brooks]

having spotted the second brown wire that is what I would expect. Why they cant put a blue wire in or a blue trace I have no idea.

[Stormbringer]

On 13/07/2017 at 18:36, blackrose said:

I haven't managed to get the element out but I'm going to order a new one from ebay anyway. Does anyone know how I check/remove the thermostat on this fridge? Apparently if the thermostat is faulty and isn't switching the fridge off when required, it soon overheats and burns out the element.

Thanks

Your fridge would be iced up and food on the top shelf would probably start to freeze. If unsure I would monitor the fridge with a clamp meter ..they pull about half an amp @ 240 v