peterjl Posted January 15, 2013 Share Posted January 15, 2013 Hi just returned from France and had a couple of odd occurences with our hot water, once on the way out and once on the way back. in both cases the hot water had been working fine and then, when we came to use hot water the next time it was as if we had to fill the water heater, the tap would just splutter air until the hot water system was full then it came out cool. I checked the dump switch and that remained closed the whole time. I had put the heater on before we left the uk and filled the water tank and boiler and let all the air out of the system. as far as i can remember the first occasion was on our first night in france after using the tunnel to cross earlier in the day. the second occasion was after we had left our campsite at 1200M altitude and our overnight stop on the way home. it was never really cold on his trip with the lowest temperatures about minus 3C. after the second occassion i tried to replicate the problem (with no success) checking water flow after every stop and using the heating alone and also using both heating and water heating. Sooo, has anyone else experienced this or have any ideas, i did wonder about the change in air pressure after tunnel or reduction in altitude but that seems a little far fetched and in any case how didi air get into the system. through all this the cold water worked fine with no indication of air in the system. i am reluctant to just go back to the dealer if i can't replicate the problem. Does anyone have a starter for 10? Peter Link to comment Share on other sites More sharing options...
Brian Kirby Posted January 15, 2013 Share Posted January 15, 2013 Which sounds as though the water heater more-or-less emptied itself. The water must, therefore, have gone somewhere. I assume you are unaware of wet patches anywhere, probably on the floor? It is unlikely to be the heater itself, as it is only intermittent. As the cold continued to work without problem, whatever it is seems confined to the hot water side. Most such systems remain slightly pressurised once fully bled of air, but yours must have lost all pressure and drawn in air to replace the missing water, to behave as you describe. Might the fresh water level have been low at the time? Are your taps micro-switched? Could there be one with that is making intermittent contact under some road conditions, so that it switches on the pump from time to time? Wet in shower tray, basin, or sink? If fresh water were low at the time, and sloshing around in the tank, it might draw in air instead of water at times, causing the water heater to part fill with air. Having pumped away most of the hot, the result would be cool water. Whereas, when the fresh water tank is reasonably full, no air would enter so the Truma would remain full, albeit it would have lost hot water and be somewhat cooler. But then, it would cool when not actually being heated, so that cooling might not strike you as abnormal. Clutching at straws, really, and musing! :-) Link to comment Share on other sites More sharing options...
lennyhb Posted January 16, 2013 Share Posted January 16, 2013 There is a vent valve on the combi similar arrangement to the older C6000 a known problem with these. It's on the water inlet connection and if it sticks open the boiler will drain with a siphon action. Link here to Truma manual the vent is item 28 in picture on page 15. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted January 16, 2013 Share Posted January 16, 2013 The only thing I can think of that might explain what you've described is that your heater lost some of its contents through the 'integrated ventilating valve' that's attached to the heater's hot-water outlet. This valve is intended to allow air to enter the heater should the FrostControl 'dump valve' open. Normally, the ventilating valve will be shut but, if it does happen to open for some reason (perhaps provoked by the air-pressure change you mention?) then some of the under-pressure water in the heater might be expelled through the ventilating-valve's venting hose that leads downwards from the valve to exit beneath the motorhome. In that scenario I'd expect some, but not all, of the heater's 10 litres water content to be lost (say 2 or 3 litres of the 10), and I would expect this limited loss to be apparent when you opened the tap. Basically, it would take a good deal less time for water to begin to run smoothly from your spluttering hot tap than when you fill the heater from empty. I'd also expect, if the heater had only partially emptied and the water in the heater had been hot to begin with, that, when the water from the tap began to run smoothly, the temperature of the water coming from the tap would not be completely cold. (I don't much like this ventilating-valve hypothesis, but I can't think of anything else that might be sporadic and might cause spluttering at the hot water taps (eg. the FrostControl valve leaking but not fully opening, or water siphoning back into the fresh-water tank) but that would not produce spluttering at the cold taps.) If the two instances of hot-tap spluttering you mention did involve the integrated ventilating valve spontaneously opening, then you may well not be able to replicate this happening. Might be worth you asking the Truma(UK) technicians about this: http://www.truma.com/uk/en/home/service-center.php Link to comment Share on other sites More sharing options...
Derek Uzzell Posted January 16, 2013 Share Posted January 16, 2013 lennyhb - 2013-01-16 9:12 AM There is a vent valve on the combi similar arrangement to the older C6000 a known problem with these. It's on the water inlet connection and if it sticks open the boiler will drain with a siphon action. Link here to Truma manual the vent is item 28 in picture on page 15. You are referring to the "integrated ventilating valve". This is connected to the heater's water outlet connection, not to its inlet. If (as I suggested above) the valve opens for some reason or fails, then water will be lost, but it won't be lost by siphonic action and, once the level of water in the heater drops down to where the valve is positioned on the heater's water reservoir, draining will cease. Plainly, if the water system includes a pressure-sensitive pump and that pump were 'On' when the ventilating valve opened/failed, then all the water in the heater's reservoir (and all the water in the motorhome's fresh-water tank) would be expelled by the pump through the ventilating-valve's vent hose, but that's another matter. I recall one instance being reported on this forum where a Truma C-Series heater's ventilating valve had failed (though I was never comfortable with what was claimed happened), but I'm not aware that valve-failure is a "known problem" with C-Series appliances. (Do you actually mean "C6000", as this Truma model ceased production in 1997?) The ventilating valve is very simple and it's fitted to Truma water-boilers as well as combination air/water heaters. As so many valves have been fitted across the years one might anticipate some valves will have failed but, generally, they seem to be very reliable. Link to comment Share on other sites More sharing options...
peterjl Posted January 16, 2013 Author Share Posted January 16, 2013 Hi Thank you for those suggestins Bian, lenny & derek. I could find no water anywhere in the van or the sinks - i looked at the time. I have now rung Truma but they could not suggest a reason either. I asked about a pressure releif valve and was told that this is the same as the frost valve - and that remained closed. I will ask the dealer to have a look when it goes in for its firts habitation service but, if i can't replicate, i am not terribly optomistic. Thank you all for your thoughts. Peter Link to comment Share on other sites More sharing options...
Derek Uzzell Posted January 16, 2013 Share Posted January 16, 2013 On-line comments (some going back over 10 years) indicate a) that the ventilation-valve fitted to the hot water outlet of Truma 'combi' heaters and water boilers can leak and b) that there's some evidence that the internals of the valve can (somehow!) disappear. In the first case water will dribble through the vent-hose: in the 2nd case water will pour through the vent-hose. What I haven't been able to find is any report of a ventilation-valve temporarily 'playing up' - they either leak and keep leaking, or water keeps pouring straight though them. Theoretically, once the Truma heater's water reservoir has been filled, there will be positive pressure within the reservoir that keeps the ventilation-valve closed. When hot water is drawn off, this pressure will be maintained by the leisure-vehicle's water pump and the heater's reservoir will remain completely full of water. In your case, there have been two separate events - well apart in time - when air has entered the reservoir (resulting in spluttering from the hot-tap until the reservoir has refilled) but, after each event, whatever caused the problem apparently cured itself. As the Truma technicians are flummoxed, and I can't see how you'll be able to replicate the 'event', you could hope it won't happen again or wait until it starts happening regularly enough (or badly enough) to be accurately diagnosed. If the problem does lie with the ventilation-valve, at least a new valve isn't that expensive. (Anyway, your Globecar should have a Truma 24 months warranty). This advert includes a photo of the latest elbow-fitting that includes the ventilation-valve: http://www.amazon.co.uk/CARAVAN-TRUMA-ULTRASTORE-FITTING-34150-01/dp/B00AI9FRG0 The colour of the elbow seems to vary (red or white) and earlier designs had a vertical vent-hose 'connection stem' rather than a right-angled stem. Part No. 34150-01 has a barb for connecting flexible hose that uses worm-drive clips, while Part No. 34150-03 is for a push-fit (John Guest type) connector. Asking-prices differ considerably. http://www.marcleleisure.co.uk/store/truma-ultrastore-elbow-fitting-with-breather-tube-flexible-conn-p-4495.html?osCsid=3e8d8c33ffc994d700b1362e50045a6b Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.