What's this I found in my fridge gas pipe and should it be there ?

[Adriaadventure]

Our Thetford N4170 fridge/Feezer was working ok before last week on Electric hook-up and then we moved to Temporary Holiday Site with no EHU so we started burning gas.
The FF was underperforming with the best it could achieve being freezer ( -10 ) and Fridge +10 deg C.
Checked the burner flame looking through the inspection hole and it was a good roaring flame but did not seem as high or as fierce as it normally is so I decide to change the burner jet assembly to a new one I carry as a spare.
In order to get enough pipe movement to remove the jet part I undid the 17mm union nut where the gas pipe joins the gas valve ( see diagram/photo ), loosened the gas valve bracket and removed the pipe/gas valve from the jet.
When looking to reassemble the pipe work and new jet I notice something white stuck in the end of the short pipe that feeds the gas into the gas valve.
This 'object' came out easily and is a small cylindrical piece of quite dense white foam 7mm long and 6.5mm diameter. It fits quite snugly into the end of the gas pipe and was obviously put there a some sort of a filter ?.
I suspect this 'bung/filter' could be restricting the gas flow being such a small area for the gas to pass through and was visibly dirty.
I reassembled the pipework and new burner jet without the small filter as I already have a Truma gas filter fitted as part of my refillable allugas bottle setup.
Does anyone know if this filter is required ?
My fridge freezer was a Thetford N3000 model fitted from new in 2018 and replaced in mid-2020 under warranty with the current N4170 model due to it apparently loosing its gas.
There is no mention of this inline filter being fitted to either model on Thetfords website nor any such filter being available as a spare from Leisure shop direct etc.
Any ideas, anyone... it seems a stupid place to hide a filter inside a gas pipe,waiting to block up but I'll stand corrected.

 

[Itsmcb]

Curious if your fridge now works properly without that little filter?

 

[Lenny HB]

I wonder if it was a bung to keep the pipe clear of debris during manufacture and someone forgot to remove it.

 

[Adriaadventure]

Curious if your fridge now works properly without that little filter?

Yes, forgot to add. There was a visible improvement in the height of the flame after removing the little filter and fitting a new jet assembly. Also the temperatures of the fridge and freezer improved by 2 or 3 degrees each.
Unfortunately I can't be sure which part was causing the problem, perhaps I should swap the jet back to the original one to try and find out but its the hassle. And at the time, after borrowing spanners from other campers on the site and the fridge freezer off I needed to get it back on as quickly as possible in the heat we we experiencing that day.

 

[Adriaadventure]

I wonder if it was a bung to keep the pipe clear of debris during manufacture and someone forgot to remove it.

It really looked as if was 'fitted' in the end of the pipe, I had to remove the short 100mm section of pipe and poke a piece of wire down it to dislodge the bung. Looking down the inside of the pipe the filter could not be pushed any further into the pipe as it could not go past the 'crease' where the olive is fitted on the steel pipe and when the bung meets the crease the end of the bung is level with the end of the pipe, like it was designed that way to sit inside the gas entry port of the gas valve.
Before dislodging the bung with a piece of wire I tried blowing hard down the pipe and could tell that some air was going through it be it with a lot of resistance hence I came to the conclusion its a filter.

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[pappajohn]

I wouldn't bother about it.
If the supply pipe needs a filter you need a different gas supplier.

 

[eurajohn]

Dometic fridges are fitted as standard with the type of device you mention, never had a Thetford so can't comment on that, I'd guess it is intended to be there

 

[eurajohn]

Should have mentioned, it is apparently to protect the delicate gas valve and is not supplied as a spare only comes with a new complete valve.

 

[fil4814]

Could it be a anti flash back device to stop the flame going down the pipe when the gas is switched off.

 

[GeoffnDee]

On a Dometic fridge It is a filter and is shown as such on the leisurespares parts diagram for the Dometic RM8550 as item 477 leisure spares part No. GR10020 in the RM8550-Armature/Fitting section (As eurajohn has said it does not appear to be stocked as a a separate item )

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[Gaston aires]

I would phone Thetford for advice. They should have a customer care department.
Phil

 

[meanders]

I would phone Thetford for advice. They should have a customer care department.
Phil

You have never tried contacting Thetford then Phil. Even the Thetford approved fitters swear about them being totally useless at customer care. I spent hours on the phone trying to speak to someone after my emails were ignored. Eventually told I needed to speak to an approved agent, who of course had told me to contact Thetford.

 

[Gaston aires]

You have never tried contacting Thetford then Phil. Even the Thetford approved fitters swear about them being totally useless at customer care. I spent hours on the phone trying to speak to someone after my emails were ignored. Eventually told I needed to speak to an approved agent, who of course had told me to contact Thetford.

No I’ve never tried to contact Thetford. Sounds grim and unacceptable. Some firm don’t deserve any business.
Phil

 

[Ian Bosman]

Our Thetford N4170 fridge/Feezer was working ok before last week on Electric hook-up and then we moved to Temporary Holiday Site with no EHU so we started burning gas.
The FF was underperforming with the best it could achieve being freezer ( -10 ) and Fridge +10 deg C.
Checked the burner flame looking through the inspection hole and it was a good roaring flame but did not seem as high or as fierce as it normally is so I decide to change the burner jet assembly to a new one I carry as a spare.
In order to get enough pipe movement to remove the jet part I undid the 17mm union nut where the gas pipe joins the gas valve ( see diagram/photo ), loosened the gas valve bracket and removed the pipe/gas valve from the jet.
When looking to reassemble the pipe work and new jet I notice something white stuck in the end of the short pipe that feeds the gas into the gas valve.
This 'object' came out easily and is a small cylindrical piece of quite dense white foam 7mm long and 6.5mm diameter. It fits quite snugly into the end of the gas pipe and was obviously put there a some sort of a filter ?.
I suspect this 'bung/filter' could be restricting the gas flow being such a small area for the gas to pass through and was visibly dirty.
I reassembled the pipework and new burner jet without the small filter as I already have a Truma gas filter fitted as part of my refillable allugas bottle setup.
Does anyone know if this filter is required ?
My fridge freezer was a Thetford N3000 model fitted from new in 2018 and replaced in mid-2020 under warranty with the current N4170 model due to it apparently loosing its gas.
There is no mention of this inline filter being fitted to either model on Thetfords website nor any such filter being available as a spare from Leisure shop direct etc.
Any ideas, anyone... it seems a stupid place to hide a filter inside a gas pipe,waiting to block up but I'll stand corrected.

My only comment is, if in the UK, you are not allowed under the law to interfere with any gas fittings unless a qualified gas fitter.

 

[Jimbohorlicks]

My only comment is, if in the UK, you are not allowed under the law to interfere with any gas fittings unless a qualified gas fitter.

Unfortunately that just applies to domestic gas fittings ,not motorhomes.

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[VXman]

You have never tried contacting Thetford then Phil. Even the Thetford approved fitters swear about them being totally useless at customer care. I spent hours on the phone trying to speak to someone after my emails were ignored. Eventually told I needed to speak to an approved agent, who of course had told me to contact Thetford.

Ah, this sounds like the Thetford I know and hate. Rang a dozen 'service centres' and none of them wanted to know unless you were a customer already. (Most service centres are dealers). One told me 'Thetford pay peanuts for warranty work'. Rang Thetford customer services and they said 'speak to your dealer or a service centre'

 

[tonyidle]

Unfortunately that just applies to domestic gas fittings ,not motorhomes.

...... and only if they don't belong to you.

 

[Adriaadventure]

Yes, forgot to add. There was a visible improvement in the height of the flame after removing the little filter and fitting a new jet assembly. Also the temperatures of the fridge and freezer improved by 2 or 3 degrees each.
Unfortunately I can't be sure which part was causing the problem, perhaps I should swap the jet back to the original one to try and find out but its the hassle. And at the time, after borrowing spanners from other campers on the site and the fridge freezer off I needed to get it back on as quickly as possible in the heat we we experiencing that day.

Refitted the original gas jet assembly today ( still left out the fibre filter pipe insert ).
Looks like the problem was the filter restricting the gas flow.
Thinking back we had an accredited mobile fitter install our Alugas bottles, truma filter unit and BBQ gas point shortly after buying the new motorhome and he installed the Tee piece and gas tap behind the bottom vent to supply the BBQ point below the fridge ( in the skirting under the vent).
I recall him searching his van for the parts to fit the BBQ point as it was late decision to have the BBQ point installed at the same visit as the gas bottles and truma filter.
I thing he removed the existing elbow fitting replacing it with the T piece to feed the BBQ point and may also have fitted the short piece of pipe with the filter in it as those parts did not look new ?.
Mystery solved, perhaps ?

 

[Adriaadventure]

Dometic fridges are fitted as standard with the type of device you mention, never had a Thetford so can't comment on that, I'd guess it is intended to be there

Found on google that a long list of Dometic fridges had this 'now discontinued' fibre in-pipe filter fitted up to about 2005. Also fault-finding advice regarding checking this filter is not blocked and causing failure or degradation of the gas flame, including lighting and burning for a short time then going out, before checking for a problem with the gas line or regulator.
There is no mention of this type of in-pipe filter being used by any other manufacturers except the dometic list of models.

 

[Adriaadventure]

Dometic fridges are fitted as standard with the type of device you mention, never had a Thetford so can't comment on that, I'd guess it is intended to be there

Found on google that a long list of Dometic fridges had this 'now discontinued' fibre in-pipe filter fitted up to about 2005. Also fault-finding advice regarding checking this filter is not blocked and causing failure or degradation of the gas flame, including lighting and burning for a short time then going out, before checking for a problem with the gas line or regulator.
There is no mention of this type of in-pipe filter being used by any other manufacturers except the dometic list of models.