Dual Tank fueling issues

We were staying with friends at the excellent Bickleigh Farm (great Birthday Party Adele – thank you) – with the intention of sleeping in the van. The first night was fine despite the outside temperature dipping below zero. However in the morning we tried to boil some water for a cup of tea which causes a heavy draw on the battery via the inverter. We switched the engine on to mitigate this, but the inverter cut-out. We switched the engine off but then the Azalai’s PC-200 control unit (for the lights and water-pump) simply died. Checking the fuses and trips showed no problem. We sent a text to Anton (OEC) to see whether there was anything else obvious that we were missing. A few minutes later Paul (OEC) called and we established that everything had been done other than checking the two ‘main’ fuses situated in the battery compartment. They were fine though. We agreed that we would need to look at the unit when the van goes in (for preliminary tail-lift fitting) this week. It was great of OEC to phone ’round  their staff and get back to us despite it being the weekend. They were surprised that unit could fail as it has a reputation for reliability.

29/11/10 UPDATE: It was the 50 amp main fuse that had blown (as it’s supposed to if the current draw on the battery is excessive) – slapped legs for Rachel and a course in ‘How to Tell if Your 50 Amp Fuse has Blown’ (I was in the back in my pants – too shy and too cold averse to go outside into the cab – so obviously not my fault!).  Solution:  hob kettle rather than electric.

Of course we would rather these snags work themselves out early; and luckily there was room in Bickleigh Farm for Saturday night so no harm done (other than losing another night’s testing and proving opportunity).

However, that wasn’t the last of it. We decided to fill up on diesel after the short drive home from the South Hams. We had noticed that the main and auxiliary tanks were remarkably showing the ‘same’ level. We wondered whether this was due to a [further] malfunction with air in the system. To check we thought we’d just fill-up the main tank then compare the two readings. Job done, and with the main tank showing full, I switched back to the auxiliary and drove-off – only for the vehicle to stall on the exit from the garage. We had the ignominy of sitting there, bonnet-up, with a busy pre-Christmas Sainsbury shopper audience waiting for the AA!

It turns out that continued cranking of the starter (minutes) will draw fuel through (I had tried that to an extent but chickened out of pushing things far enough for fear of overheating the starter motor or flattening the battery. It is important to make sure that in extended cranking, to make sure that the starter motor does get time to cool – So if it happens to you crank for a minute or two then stop to let the starter cool, then try again…..). The AA chap explained that the Puma engine was “a pig” to bleed and suggested that it might be worth installing a feeder pump into the set-up to counteract the ingress of air back into the feeds. We’ll put that to OEC this week too. From early experience it does seem that the set-up is prone to air lock related problems at switch-over of tanks.

29/11/10 UPDATE: OEC advise that due to the relatively long construction of the auxiliary tank, the contents will slosh and pool to one end depending on the attitude of the vehicle: Nose-down or braking puts the fuel towards the front of the tank and might break the feed (which is at the rear). Solution: Don’t run the auxiliary tank much below a third full. (We had 20 litres remaining when we had the problems at the garage)

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