Trauma gas valve/regulator

[clifty]

Hi, can anyone help my friend with an 18month old hobby based on the transit chassis. I remember an article in mmm re gas valves/ regulators failing due to a reaction from the gas and the rubber pipe causing a fluid build up clogging the valve...but like most of us cannot find the article. He's waiting for a new valve regulator to be fitted but i seem to remember there was some advice about routing the flexible hoses to minimise the problem?

thanks...still enjoying our Rapido mh.

[Guest Tracker]

Try a search in motorhome matters using 'regulators' as a keyword.

 

The problem seems to be random and seems to be mainly when the regulator is sited lower that the top of the gas bottle which seems to allow any oily sediment to form when the gas reacts with the rubber hose (bad design - wrong sort of rubber maybe?) and then run into the regulator - which it then blocks - rather than back down into the gas bottle.

 

I've never had this problem so I may be wrong but if I'm not the only lasting cures are to relocate the regulator higher up the bulk head - where it should have been in the first place - or use non rubber pigtails.

[BrianR]

The advice was to ensure that the regulator was mounted higher than the top of the gas bottle, so that the "gunge" developing inside the pipe from the bottle to the regulator could not run down the pipe into the regulator.

[Keithl]

Hi Clifty,

 

Have a look on the Gaslow website, they give an explanation of the problem and list stainless hoses as a permanent cure.

They also offer a regulator and hose package with a 5 year warranty if you need to replace the regulator as well.

I have just fitted one of their stainless hoses as my original rubber hose was due for replacement on age.

 

Keith.

[Guest peter]

I think the stainless hoses have a PTFE liner so is totally inert.

[Derek Uzzell]

Clifty

 

There are two theories about this. The first explanation is the simple one - that oily 'refinement residues' in LPG cylinders find their way into the regulator and clog it. The second theory suggests that condensed LPG reacts with the materials from which flexible gas-hoses are made and the resultant muck that forms gets into the regulator.

 

Whatever the cause (and both explanations are plausible), the recommended 'fix' - at least in the UK - involves optimising the positioning of the bulkhead-mounted regulator and the flexible hose that links regulator to LPG-bottle.

 

Calor's advice (backed by Truma) is that the regulator should be positioned as high as possible in the leisure-vehicle's gas locker. The regulator should be mounted vertically, with its gas INLET uppermost. The flexible gas hose should be as short as practical and ascend from LPG-bottle OUTLET to regulator INLET without any downwards curves/loops that might trap condensed LPG. Achieving this arrangement in many leisure-vehicles may be difficult and often involve fitting a 90° elbow to the regulator's inlet. This set-up will minimise the risk of LPG entering the regulator in liquid (or mucky!) form and/or remaining inside the regulator.

 

Further suggestions - initiated primarily by the Gaslow company - are to use gas-hoses with a (reasonably) flexible convoluted stainless-steel core (which removes any possibility of a chemical reaction between hose and condensed LPG) and employ a Clesse-branded regulator that is supposedly 'bomb proof'. Plainly, if Calor's installation advice and Gaslow's product recommendations are all followed, there's every chance that regulator-related problems will be avoided.

 

My own feeling (and I've had two Truma bulkhead-mounted regulators fail) is that the most important thing is to ensure that the flexible hose 'climbs' from the LPG-bottle for a reasonable distance. This should discourage any muck that may be in the LPG-bottle from reaching the regulator and should encourage any liquid gas emerging from the bottle to flow back from whence it came.

 

Truma has always claimed that, when 'muck' has been found in regulators and gas-hoses, chemical analysis has proven that the constituents of the muck cannot have come from Truma-marketed gas-hoses. (Draw your own conclusions then as to which of the two theories I mentioned in my first paragraph Truma favours...) Apparently, it is also the case that laboratory experiments to try to produce the muck-forming reaction between gas and flexible hose have been unsuccessful. However, a Truma representative did assure me that examination of every failed Truma-branded regulator that had been returned under warranty had revealed that the regulator had been 'wet' inside. There's been a lot of previous forum discussion about regulator failures and I recall someone posting photos of a disassembled Truma regulator with the internal diaphragms badly swollen, so it's possible that many Truma regulators fail due to liquid LPG damaging their internals rather than them actually being 'clogged' by muck.

 

Not sure what gas regulator a 2007 Hobby would start out with when it left the factory. Originally my own 2005 Germany-bought Hobby had a simple 30mbar Truma/GOK regulator that attached directly to a German propane bottle and I re-jigged the system to accept a Truma/GOK bulkhead-mounted regulator. I would have thought a 2007 Hobby might have Truma's Secu-Motion regulator/hose combination factory-fitted as standard and, if that were so, it would be reasonable to assume that the installation should conform in principle to Calor's recommendations.

 

It used to be the case that Truma would swap failed regulators without argument and (because there had been so many failures and UK leisure-vehicle manufacturers had become uppity) there was some sort of deal between Truma and UK motorhome/caravan builders that this arrangement would continue. It would seem that things have now changed. See

 

http://www.outandaboutlive.co.uk/forums/forums/thread-view.asp?tid=14753&posts=11

 

(There could well have been a piece in MMM about this, but there definitely was one in the July 2007 (page 71) issue of the Caravan Club Magazine.)

[Derek Uzzell]

The MMM article Clifty mentions is quite likely John Wickersham's "GAS STARVATION" piece on pages 209-214 of the MMM April 2007 issue.

[GJH]

I replaced the rubber hose on our van with one of the Gaslow ones last year. Apart from avoiding the potential residue problem there is another advantage from my point of view in that the connection to the bottle is made using a hand wheel rather than having to use a spanner.

 

Our gas locker takes two 6Kg bottles but it is only possible to use the spanner on the left hand bottle. That meant when one ran out I had to take both bottles out of the locker and swap them round before connecting to the full one - a bit of a "clart on" when you are in the middle of using the gas.

 

Now I just detach the hose from the empty bottle and connect it to the full one, leaving the changing round of bottles until we are back home and I can do it at my leisure.

 

Graham

[lennyhb]

I thought the problem only occurs on British vans fitted with the bulkhead mounted Truma regulator. An 18 month old Hobby I would expect to have

a bottle mounted regulator.

If the van is only 18 months old it should still be under warranty has your friend contacted the supplying dealer?

[PJay]

lennyhb - 2009-04-21 3:23 PM

 

I thought the problem only occurs on British vans fitted with the bulkhead mounted Truma regulator. An 18 month old Hobby I would expect to have

a bottle mounted regulator.

If the van is only 18 months old it should still be under warranty has your friend contacted the supplying dealer?

We had the same problem in a one yearol van, as was in France at the time had trouble getting a replacement (bieing a British Van) Were told by dealer that Trauma would not cover on warranty! But they agreed to re-ibuse us (About£28) we replaced the rubber tube with a stainless one, when we returned home.

PJay

[Usinmyknaus]

My van's regulator (which is fitted above the tanks so I had not expected to have this problem) failed in France last Autumn and on inspection it was full to the gunnels with a yellow-ish brown liquid. Replaced free of charge on return to the UK by Lowdhams.

 

I recently fitted a Gaslow stainless steel hose and in response to Derek's advice above, I yesterday re-positioned it so that there are no downward loops. Hope that's enough to prevent a repeat non-performance.

 

Bob

[Derek Uzzell]

John Wickersham's MMM article states that, from September 2003 onwards, the gas systems of British-built motorhomes included a 'fixed' bulkhead-mounted 2-stage 30mbar regulator rather than the single-stage 28mbar or 37mbar on-bottle regulator that had been traditionally employed.

 

But French-built motorhomes had, for years before 2003, been fitted with a bulkhead-mounted regulator (normally a 37mbar single-stage one) and there had been many, many complaints in France of muck-blocked regulators and solenoid-operated gas valves. In fact, my understanding is that French regulations demand that a bulkhead-mounted regulator be used on motorhomes sold new in France.

 

JW's article says that 2-stage 30mbar bulkhead-mounted regulators were generally adopted by motorhome/caravan constructors throughout Europe, except in Germany where many manufacturers continued to use a single-stage 30mbar bottle-mounted regulator. He instances Dethleffs as one example and, as I mentioned earlier, Hobby was another maker that bucked the trend. Obviously, if one bought a German-built motorhome in Germany as I did, it came with a German-specification gas system which, for a 2005 Hobby, meant having an on-bottle regulator. However, Hobby motorhomes sold in France had 'fixed' regulators and I'm pretty sure RHD Hobbys sold through Brownhills did too.

 

In 2007 German regulations demanded that specialised regulators (eg. the Truma/GOK SecuMotion/Drive-Safe product) be fitted to new motorhomes to comply with rules relating to operating LPG-fuelled heaters while the vehicle was being driven. This will undoubtedly have killed off the German practice of using on-bottle regulators on new motorhomes - though I expect it continues with German-built caravans. That's one reason why I thought an 18-month old Hobby's regulator would be bulkhead-mounted rather than on-bottle; the other reason being that Clifty's original posting's title and text strongly suggests that his pal's failed regulator is wall-mounted and probably of the SecuMotion/Drive-Safe type.

 

I think Truma/GOK regulators may have a 24 months warranty period, but Truma evidently won't now exchange failed regulators under warranty without first establishing the cause of the failure. The Installation Instructions for SecuMotion/Drive-Safe regulators are more specific than those for earlier Truma/GOK fixed regulators regarding positioning /orientation of the regulator (basically they match Calor's advice), so, if an installation does not conform to those instructions and/or 'muck' were found in the gas hoses and/or regulator, it's quite possible Truma would seek to reject a claim for free replacement. It may also be worth remembering that 'old' Brownhills would have been the sole official Hobby UK-dealership during 2007 but 'new' Brownhills no longer has a Hobby agency... (Clifty has not mentioned that his friend has encountered warranty-related arguments, so none of this may be directly relevant.)