Truma bulkhead regulators

[HarryM1BYT]

Some of you with caravans might already be aware of this issue, but maybe some not.....

Originally the regulators were mounted on the gas bottles, 37mb for propane and 28mb for butane, but things changed in around 2003 where a new standard was introduced where a 30mb regulator was mounted on the bulkhead and then an high pressure pigtail pipe was used from the bottle to the regulator, most commonly a Truma 2 stage regulator was used, with various adaptors from the pigtail to fit the bottle type. 30mb was used for both butane , propane and a butane propane mix.

Since then there have been ongoing problems with the HP input stage of these regulators becoming choked up with an oily substance, the source of which no one has properly identified. The regulator manufacturer blames the gas bottle company, the gas bottle company blames the HP hoses - with the carvan owners in the middle - forking out each time for new regulators and lots of discussion on the caravan forums about the problem. A suggested fix is to use a stainless steel lined HP pigtail.

This time around, I decied to invest in BP/MacGas light bottles and not sure then how to connect these to my caravan I bought a BP type snap on regulator and temprorarily used a nozzle and low pressure hose onto the caravan, bypassing the bulhead regulator.

This week, I managed to work out what bits I needed to get to reuse the bulkhead regulator, ordered them and fitted them today. Due to the regulator being off the van I noticed the oil dribbling out of its HP input port. Which got me thinking....

The standard way to install the regulators, is with the HP pigtail going in at the top, the 10mm copper to the van out of the bottom - flow from top to bottom. Which means the oil is blown into the reg and once in it cannot drain. Now if I were to mount the regulator upside down, any oil will drain back down into the pigtail and when ever the tail is removed from the bottle it will drain straight out.

[Bprepared]

Hi Harry,

What you suggest should theoretically work, and is along the same lines as the caravan manufacturers are have been doing on new model vans for the last couple of years.
This 'oil' comes from the high pressure gas reacting with the rubber causing the Plasticiser to be released from the rubber. Since the plasticiser is a fluid it flows to the lowest point which if the regulator is below the bottle it ends up there. Truma started supplying elbows for the high pressure side of the regulator(and the most recent versions have this inter grated into the regulator itself), but this only helps if the regulator is repositioned higher than the bottle, which as a caravan maintenance engineer I now do as a matter of course when ever I get a call out for a dead reg.
However, this only reduces the time between failures as inevitably the plasticiser can still be blown up the pipe by the flow of the high pressure gas, so I suspect that similarly with your modification it will not solve the problem completely but will prolong the life of the regulator even further.
This why they are now looking at gas tight flexible metal pipes to remove the source of the plasticiser altogether.

[HarryM1BYT]

Originally Posted by Bprepared

Hi Harry,

What you suggest should theoretically work, and is along the same lines as the caravan manufacturers are have been doing on new model vans for the last couple of years.
This 'oil' comes from the high pressure gas reacting with the rubber causing the Plasticiser to be released from the rubber. Since the plasticiser is a fluid it flows to the lowest point which if the regulator is below the bottle it ends up there. Truma started supplying elbows for the high pressure side of the regulator(and the most recent versions have this inter grated into the regulator itself), but this only helps if the regulator is repositioned higher than the bottle, which as a caravan maintenance engineer I now do as a matter of course when ever I get a call out for a dead reg.
However, this only reduces the time between failures as inevitably the plasticiser can still be blown up the pipe by the flow of the high pressure gas, so I suspect that similarly with your modification it will not solve the problem completely but will prolong the life of the regulator even further.
This why they are now looking at gas tight flexible metal pipes to remove the source of the plasticiser altogether.

So are you agreeing with my mounting the regulator upside down?

I have heard mount it above the bottle height, but it still semms not to help that much.

It seems an obvious solution to me, if its do-able - has no one else tried it?

Upside down, any oil in the pipe would drain straight out if the pipe were disconnected and simply left hanging vertically from the regulator, when not in use.

[Bprepared]

I agree that it merits investigation, but I don't believe it will solve the problem entirely because in theory the higher reg position should provide the same results, but obviously doesn't. As I previously stated I believe this is due to the high pressure gas flow blowing the plasticiser into the reg which might still happen if it is mounted upside down, and so wouldn't necessarily cure the problem. I will double check with my contact at truma when I get back from my holiday to check that the reg can be mounted upside-down, but I seem to recall from my training that it may cause some issues with the reg internal working as they are not quite the simple diaphragm layout you have with the bottle mount regs so please bear with me and I'll get back to you as soon as I can.

[HarryM1BYT]

Thanks, I look forward to their reply.

[HarryM1BYT]

I've just managed to find a phone number for Truma UK, so I rang them - you can't beat information first hand and I had a long natter with their technical bod...

Providing my regulator is not a crash sensor type, then I can mount it in any orientation I like, but he said it will not make any difference, the oil will still get to it and the only fix is their filter. He suggested that all regulators suffer from it irrespective of make, though I ommited to quiz him on why bottle mount regulators seem not to be affected.

He said the problem is due to impurities in the gas, introduced in the past 7 or so years and were it not for the regulator catching the oil, the appliances would suffer. The impurities boil out of the gas and condense in the regulator causing swelling up of the diaphram. The only solution is a Truma filter and a new regulator, then they will guarantee the regulator.

Despite their saying they have tried everything, maybe including upside down, it seems logically better for the oil to at least have an escape route and be fighting against gravity to get into the regulator, so I'll reinstall it inverted.

[macafee2]

Harry,
is this the filter Truma were referring to?
http://compare.ebay.co.uk/like/14094...ype=pla&crdt=0

There was a time Truma were replacing the regulators FOC but have stopped doing it now.
macafee2

[HarryM1BYT]

Originally Posted by macafee2

Harry,
is this the filter Truma were referring to?
http://compare.ebay.co.uk/like/14094...ype=pla&crdt=0

There was a time Truma were replacing the regulators FOC but have stopped doing it now.
macafee2

The GOK regulator, yes.

I've fitted it upside down now. The 400mm pigtail actually works better with it hanging straight down from the reg.. It makes it easier for reaching short and taller bottles.