chas Posted August 21, 2014 Share Posted August 21, 2014 Does anyone have any ideas on how to free up an airlock on my motorhome. Having completed some water tank work and checked for any obvious kinks ect the water is only about half the pressure it used to be. Thanks. Link to comment Share on other sites More sharing options...
Brian Kirby Posted August 21, 2014 Share Posted August 21, 2014 What caused you to diagnose an airlock? Also, is the pump immersed, or external to the tank? Link to comment Share on other sites More sharing options...
Guest JudgeMental Posted August 21, 2014 Share Posted August 21, 2014 Brian Kirby - 2014-08-21 12:27 PM What caused you to diagnose an airlock? Also, is the pump immersed, or external to the tank? if the pumps immersed in tank, put your hand in tank and jiggle pump around a bit (with tap on) or tap it on side of tank...mine needs this very occasionally. Link to comment Share on other sites More sharing options...
chas Posted August 21, 2014 Author Share Posted August 21, 2014 Thanks for the replies, yes the pump is a submersible one, and will try the suggested methods, air lock problem was the only thing I could think of at the time. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted August 21, 2014 Share Posted August 21, 2014 See also my comments on your Hints & Tips inquiry http://www.outandaboutlive.co.uk/forums/Motorhomes/Hints-and-Tips/partial-air-lock-/35824/#M431408 Link to comment Share on other sites More sharing options...
Brian Kirby Posted August 21, 2014 Share Posted August 21, 2014 One thing that does occur to me is if the van has a Turma Combi heater, have you got all the air out of that? They can be a bit tricky to fully bleed of air on some installations, and I have noticed that if all air is not out of the Combi, leaving the heater jacket only part filled, the flow from the taps can be a bit sluggish. It seems the pump merely compresses any air left in the Combi, which reduces the flow at the taps. Also, is the Combi drain valve fully closed after you did the work? I assume you must have drained the system, and it is easy to forget that valve. Have you tried moving the tap levers (assuming mixer taps, and including the shower) from hot to cold while operating the pump? This sometimes results of a bit of extra spitting. If the toilet flush is fed from the tank, make sure it is flushing freely and not blowing air. Any air anywhere in the system is liable to have some effect on the outputs from the taps. Finally, turn on the water heating at its highest setting, and let it heat fully. Then, try re-bleeding at the taps, shower, and toilet while the water is hot. The heat makes the air expand, and this seems sometimes to do the trick. If that doesn't work, take the van for a run of about 15 - 20 miles, and then see if more air is produced. This sometimes teases an air bubble out of hiding. It has always seemed to me that the water flow is improved after the water has been heated, and the van driven. Hope this helps. Link to comment Share on other sites More sharing options...
chas Posted August 21, 2014 Author Share Posted August 21, 2014 Thank you for your replies, first of all the water system does not feed the toilet. the boiler is a Truma Ultrastore Rapid. Only the fresh water tank was drained off to allow the work on the tank to take place. I will indeed attempt to remove the submersible pump from the tank to check for any rubbish it may have in it . I have also now emptied the boiler completely of water, and refilled main tank, which of course also refills the boiler. All these actions + a short run around in van did not work, I shall be checking pump for blockage and also heat up the boiler to see if that will work. The taps are mixer taps and have tried running them on both hot and cold settings with no luck, although the boiler was not hot at the time . I will let you know if I am successful. (lol) P S Every winter I drain down completely and come spring fill back up, with no problems. ;-) Link to comment Share on other sites More sharing options...
Guest JudgeMental Posted August 21, 2014 Share Posted August 21, 2014 there may well be no need to remove, simply tap on side of tank (while submersed) with tap open. This may well do the trick. will probably gurgle and splutter then start working...fingers crossed. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted August 22, 2014 Share Posted August 22, 2014 JudgeMental - 2014-08-21 12:48 PM Brian Kirby - 2014-08-21 12:27 PM What caused you to diagnose an airlock? Also, is the pump immersed, or external to the tank? if the pumps immersed in tank, put your hand in tank and jiggle pump around a bit (with tap on) or tap it on side of tank...mine needs this very occasionally. Are you saying that you occasionally experience the same problem chas has - that water-pressure is low at all the water outlets - and that jiggling the submerged pump cures this, or something else? Unlike diaphragm pumps (eg. SHURflo ones) submersible water-pumps are ‘non-priming’. Although they will normally achieve a state of prime when covered with water, expelling the air in the pump along the water feed-line, this may not always happen. In his book “The Motorcaravan Manual” John Wickersham advises as follows: “Airlocks in submersibles. If a submersible pump doesn’t deliver water after it has been dropped into a water container, there are probably air bubbles caught in the casing. To expel air bubbles, disconnect the feed pipe fromthe motorcaravan. Keep the pump under the water and swing the feed pipe so that the unit bumps several times against the side of the wayer container. This dislodges air bubbles, some of which are sometimes seen rising in the water. Alternatively air is dispelled through the upper end of the hose. To reduce the likelihood of air bubbles getting caught in a pump casing, more recent products feature an air release hole in the top of the casing. The Whale 881 is an example.” JW’s advice is oriented towards usage of a submersible pump with an ‘Aquaroll-type’ water container, but the thinking behind bumping/jiggling the pump (or tapping the water container) applies equally to when the pump is in an onboard water tank - it’s to make the pump prime so that it will begin to deliver water. But chas’s pump does prime and does deliver water, just at a reduced pressure. You’ll see from chas’s latest posting on the Hints & Tips thread that he has tried the tapping-the-pump ploy without success and that there does not appear to be any obvious blockage at the pump itself. His current thinking is that the pump itself (some 9 years old) may be the culprit. Me, I’d still want to check whether the non-return valve is functioning properly, but if it is then a new pump seems likely to be needed. (I guess there’s the possibility that the voltage at the pump has, for some peculiar reason, become lowered, but that’s clutching at straws.) Link to comment Share on other sites More sharing options...
Guest JudgeMental Posted August 22, 2014 Share Posted August 22, 2014 my practical experience is as follows. have only had a problem with pump on this van. When I picked it up in Germany and stayed on Aire local to dealer, that evening (after filling tank) water was trickling out. when I returned to the dealer next morning the chap showed me how to get it to operate (as described) It has happened once since when filling an empty tank. I kinda assumed pump was not self priming..... surely such a simple potential fix worth a go, but did not realize Chris had tried this...but were taps open/operating when he did it, as it can take a few taps before it gurgles and rushes out...... Link to comment Share on other sites More sharing options...
Derek Uzzell Posted August 22, 2014 Share Posted August 22, 2014 On the Hints&Tips thread chas says “...water will pump ok to the taps etc but at about half the pressure, as before it was a very fast flow”. If a pre-problem pressure of 20psi is assumed, half the pressure would be 10psi. That’s still not great, but it’s definitely not the trickle that happens when a submersible pump fails to prime. It will be necessary (or very advisable) to have taps open when attempting to encourage a reluctant submersible pump to prime, but if water is flowing from the taps consistently it can safely be said that the pump is primed. Link to comment Share on other sites More sharing options...
chas Posted August 23, 2014 Author Share Posted August 23, 2014 Just to bring you up to date, I managed to get the submersible pump out of the tank, it is a Reich Twin pump 19litres min 1.4 bar. When I disconnected from its power source doing the tank modification I colour coded the wires, "always do that". Had no joy with trying to get rid of possible airlock and on looking at another forum :$ found that particular pump if wired up other way round will work but at about half pressure. I decided to wire it other way round, It now works perfectly :D . I can only imagine I MUST have coded them wrong , its the only explanation. This info may be of use for anyone else with that model of pump, they appear to be used often in Hymers. Thanks for all the input. Link to comment Share on other sites More sharing options...
Brian Kirby Posted August 23, 2014 Share Posted August 23, 2014 Well done! No new pump needed, and useful information gained. What more could we all want? Thanks Chas. Link to comment Share on other sites More sharing options...
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