Styve100 Posted February 21, 2019 Share Posted February 21, 2019 Hi all, doing a few jobs on motorhome ready for this year. One thing I noticed is I needed to put quite a bit of water in before my pump would prime, it looks like a possibly whale submersible pump in the tank at an angle, I seem to have to fill the tank at least half before it would pump. I was thinking when travelling i would like as least water in as possible, but, would like some in to use en route, I know some of you will say drain it, but i dont really want to and surely a lot of people who wild camp travel with some water in. So I was thinking of changing for an inline pump such as I had in my previous caravan, a bailey unicorn. They seem to be self priming and safe to run dry. This model i saw seems ok? Fiamma Aqua 8 Water Pump - 1.5 Bar, 12v, 10 Litre is the 10 litre a per minute figure? Also as an alternative, given i have the whale adjustable pressure switch, many years ago in my swift caravan I fitted an electronic switch I got off ebay, didnt matter what the voltage was the unit adjusted and turned on and off. I cant seem to find these units now and i am surprised? However idealy i would like to fit an inline pump. Link to comment Share on other sites More sharing options...
Willum Posted February 21, 2019 Share Posted February 21, 2019 My personal choice would be a Shurflo. There are options, so make sure you get the right voltage (12?) and bar rating (probably about 1.5 bar/20psi) for your system. Being American :-S they use psi. They will run dry without problems, are very reliable and spares are readily available. Put an in-line filter before the pump, something to hold the draw pipe on the bottom of the tank (I use one of their filters on the end of the pipe to do it) and check the supply cable and fusing are right for it. I have surge damper and an override switch which allows me to keep a relatively constant pressure in the system for showering. I use a 10", full flow filter housing with a carbon cartridge on the output of mine and a few extra valves and pipes to allow me to filter all the water to take out chlorine/bad taste, whatever and I can use it to pump water from a barrel into the tank if I wish. Saves old bones/muscles lifting 20 litres you've lugged/shopping trollied from a distant tap. Take out the filter cartridge (it filters out the cleaner) and I can pump cleaner straight into the pipes. All you then need to do is look after the tank properly and you can drink the lovely, fresh tasting water with impunity. The usual caveats ref making sure it's suitable.............. Will Link to comment Share on other sites More sharing options...
EJB Posted February 21, 2019 Share Posted February 21, 2019 Many of us travel with full tanks ;-) Link to comment Share on other sites More sharing options...
DickB Posted February 24, 2019 Share Posted February 24, 2019 I got fed up with my in tank pump either cycling on/off intermittently for no reason (no air or water leaks), or the pressure switch chattering if the shower was in use and thus low pressure. The Whale external pressure switch is apparently very voltage sensitive and it was impossible to get a steady performance. I have just replaced the pump (German) and the Whale switch with a Flojet external pump with an integral pressure switch, which is the system I had on my boat for 30 years. For me the Flojet was the only one that would fit in the limited space under the seat and it came with 12mm push fit connectors which match the rest of the system. A W4 in line strainer also with 12mm push fit connectors is fitted in the suction pipe before the pump. I have yet to test the system, but from experience I have no reason to doubt that it will be fine. Dick Link to comment Share on other sites More sharing options...
david lloyd Posted February 25, 2019 Share Posted February 25, 2019 Had all the similar problems with the whale submersible and pressure switch so replaced both with a Whalemaster 30 psi inline pump. I have a 3M micribiogical filter on the kitchen supply and the Shurflo 20 psi struggled to maintain steady flow through this. When the submersible was removed it had a very rusty jubilee clip holding the water feed pipe on! David Link to comment Share on other sites More sharing options...
Derek Uzzell Posted February 25, 2019 Share Posted February 25, 2019 There’s a long discussion about the Whale pressure-sensitive switch in this 2016 CaravanTalk forum thread https://www.caravantalk.co.uk/community/topic/114372-whale-pressure-switch-alternative/ where it’s (persuasively) claimed that the ‘voltage sensitivity’ does nor relate to the switch per se, but to the submersible pump. I note that Comet markets an in-line pressure-switch that shuts off at 1.4 bar pressure https://tinyurl.com/y5m4ez3v but it’s anybody’s guess whether it would be preferable for Steve to replace his present (probably on its last legs) submersible pump with a similar type (perhaps a Comet equivalent) and replace the Whale switch with a Comet switch, or go down the pressure-sensitive diaphragm water-pump route that he is considering taking. The SHURflo pump commonly fitted to motorhomes is the Trail King 7-litres-per-minute 20psi-shut-off-pressure model as advertised here https://www.ebay.co.uk/p/SHURFLO-20psi-Trailking-Water-Pump-12volt-2095-204-412-Caravan-Motorhome/18023400655?iid=171547564513 There is a version with a 30psi-shut-off-pressure https://tinyurl.com/yy4dz34m but the higher the shut-off-pressure, the more the motorhome’s water hoses and joint-seals will be stressed. My three motorhomes have all had a SHURflo Trail King 7lpm/20psi pump and this has provided adequate water-flow/pressure at taps and the shower-head. Link to comment Share on other sites More sharing options...
Willum Posted February 25, 2019 Share Posted February 25, 2019 Reading the other responses, my reply probably wan't detailed enough in that I still use the tap microswitches under normal circumstances and the override switch for the shower, letting the pump's own pressure switch (20psi/1.4bar) make sure the system isn't over pressurised. Derek's warning that the 30psi model may be pushing the limits of the system's capability is well worth considering. One other note is that despite the quietness of the Shurflo it most certainly will send a vibration through any panel it is secured onto unless it is well isolated. Its built-in rubber feet aren't enough. I also use a length of very flexible silicon pipe either side of the pump to damp out vibration transmission back through the pipework. It isn't a bad vibration, or noise, it is very quiet in itself, but it's there and doesn't have the advantage of a tank full of water to soak up the sound and movement as does a submersible. I guess the same will apply to most external pumps, a true centrifugal producing the least. Will Link to comment Share on other sites More sharing options...
Styve100 Posted February 26, 2019 Author Share Posted February 26, 2019 thank you all for the brilliant replies, i will keep you posted with what I achieve. I note the pressure warnings. Currently the pump seems ok when it is primed, it is quiet and the flow is probably the best i have had in all my caravanning years, but the amount I have to put in and the pressure switch is the issue for me. The problem with the switches is, when the voltage is reduced when not on hook up, means the pump cannot attain the same pressure to switch off the pressure switch. Link to comment Share on other sites More sharing options...
Willum Posted February 26, 2019 Share Posted February 26, 2019 Styve100 - 2019-02-26 8:25 AM thank you all for the brilliant replies, i will keep you posted with what I achieve. I note the pressure warnings. Currently the pump seems ok when it is primed, it is quiet and the flow is probably the best i have had in all my caravanning years, but the amount I have to put in and the pressure switch is the issue for me. The problem with the switches is, when the voltage is reduced when not on hook up, means the pump cannot attain the same pressure to switch off the pressure switch. Sounds familiar. I suspect there's also a possibility the non-retyrn valve in the pump - if it has/ever had one - isn't playing the game and letting the system drain back to the tank, hence the re-priming which will be better with more water in the tank. The advantage of the pressure switch built into the Shurflo (other marques may be the same) is that it is mechanical and not reliant on voltage. As an aside, take note of the manufacturer's instructions if you decide you need to adjust it. It's not at all difficult but it is possible to get it all out of kilter if you don't observe the limits they say. Will Link to comment Share on other sites More sharing options...
Styve100 Posted February 27, 2019 Author Share Posted February 27, 2019 Hi All, thanks for the contributions. Just to let you know have finished the job, took everything out and bought a shurflow trail king, 20psi and 10 l/m pump, fitted a surge damper too although recommended didnt need one, thought it best as if there were problems it would save a journey. Quite simple to fit, with a new pick up pipe in the tank, the end cut at an angle so its not sucked to the bottom of the tank and gets no water, the strainer supplied is fitted going to the pump, you have to short the wires going to the pressure switch obviously as this is removed and needs to be shorted to put power to the motor. Filled tank enough and all tried, very good flow and pressure and not really noisy, screwed to the floor once the cushions are back on its not really noticeable. Very pleased with the instal and means I now how no worries of adjusting a pressure switch and can have little water in the tank on the move until based. Link to comment Share on other sites More sharing options...
Willum Posted February 27, 2019 Share Posted February 27, 2019 Styve100 - 2019-02-27 11:56 AM ................ you have to short the wires going to the pressure switch obviously as this is removed and needs to be shorted to put power to the motor................ I'm a bit baffled - and worried - by the bit about shorting the wires to the pressure switch. I hope I've got this wrong and I've misunderstood what you wrote but unless you are talking about a very different Trailking to the ones I know, ie, like this one: https://www.ebay.co.uk/itm/SHURFLO-20psi-TrailKing-Water-Pump-12volt-2095-204-412-Caravan-Motorhome-/161081812748?_trksid=p2385738.m4383.l4275.c10 the pressure switch is built into the pump head and is there as a safety device to protect the pump and make sure that the system can't overpressure. If I'm right, the pump is the one I think and you have microswitches on your taps, it's quite possible to crack a tap open a little, close the microswitch with little or no water coming from a tap outlet and the pump will run continuously. The pump will run until it achieves it's max theoretical pressure, stalls from overpressure, blows the supply fuse, sets fire to the wiring because it's stalled and shorted the windings, or - and this is the most probable - bursts a pipe, fitting, or very expensive water heater core. I've never put one to the test but they are similar to a swashplate pump, the sort of thing that achieves in excess of 2000 psi in your pressure washer. It won't get that high because the motor hasn't the power but it will certainly exceed anything the pipework/heater can survive. I would REALLY re-einstate that pressure switch on the end of the pump head. It won't affect the flow rate but it may well save a big, leaky mess. Will Link to comment Share on other sites More sharing options...
Derek Uzzell Posted February 27, 2019 Share Posted February 27, 2019 Styve100 - 2019-02-27 11:56 AM ...bought a shurflow trail king, 20psi and 10 l/m pump... Are you sure about that specification? Trail King 7s have a 7lpm flow-rate (as evidenced by their model-number) and a 20si or 30psi shut-off pressure. Trail King 10s have a 10lpm flow-rate and a 30psi or 45psi shut-off pressure. Link to comment Share on other sites More sharing options...
Styve100 Posted February 27, 2019 Author Share Posted February 27, 2019 on the existing wiring on the van, you have to short the wires that went to the pressure switch, nothing on the the new pump, if you dont you would never get a supply to the pump, sorry if i wasnt clear. Link to comment Share on other sites More sharing options...
Willum Posted February 27, 2019 Share Posted February 27, 2019 Styve100 - 2019-02-27 6:43 PM on the existing wiring on the van, you have to short the wires that went to the pressure switch, nothing on the the new pump, if you dont you would never get a supply to the pump, sorry if i wasnt clear. Ah! I guess the 'pressure switch' you originally referred to is the one already fitted to control your old in-tank pump? If so, my previous warning won't apply. Personally, I'd get a suitable straight coupler and take the old pressure switch out of the circuit altogether. Less chance of a leak/blockage/complication, added to which, if you chuck it, you win back a nat's doo-dah of payload :-D Will Link to comment Share on other sites More sharing options...
Derek Uzzell Posted February 28, 2019 Share Posted February 28, 2019 747Heavy - 2019-02-27 9:16 PM ...Personally, I'd get a suitable straight coupler and take the old pressure switch out of the circuit altogether... Will So would I... With the original submersible water-pump replaced by a SHURflo pump, the Whale in-line pressure switch becomes superfluous. I don’t know if leaving the Whale switch in the water-supply circuit would have the potential to restrict the water-flow, but if the switch were removed and replaced by a suitable straight coupler (or by a new longer piece of water hose) and the 12V cables to-and-from the pump just connected together, that would certainly simplify the system. Leaving the now-redundant Whale pump in situ could also result in some head-scratching if the motorhome is eventually sold. Link to comment Share on other sites More sharing options...
Styve100 Posted February 28, 2019 Author Share Posted February 28, 2019 Hi, I did, I took everything out.... The shurflo pump has both its own pressure switch and non return valve, so the old switch is redundant, and removed. A strainer is important before the pump is important as you do it appears get grit in our water sometimes, and this can block the non return valve as in a Bailey i had the pump kept starting briefly every half hour or so, had to replace the pump diaphragm . Link to comment Share on other sites More sharing options...
Styve100 Posted March 1, 2019 Author Share Posted March 1, 2019 finally i did a video just to show what i had done. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted March 1, 2019 Share Posted March 1, 2019 I’ve no hands-on experience of submersible water-pumps, but is it imperative that they be upright (or near enough upright) in the fresh-water tank? I note that, in your original postiing, you said "I seem to have to fill the tank at least half before it (the pump) would pump” but that can’t be normal behaviour, just peculiar to your pump. I would have thought that as long as a modern submersible pump is actually submerged in the water, it ought to self-prime and pump OK. So, if a submersible pump can be horizontal (or near enough horizontal) in the water tank, the pump could operate with a relatively small quantity of water in the tank. Link to comment Share on other sites More sharing options...
Styve100 Posted March 9, 2019 Author Share Posted March 9, 2019 Hi, no these pumps have to be near vertical, they have to fill with water, they will not self prime and if there is any restriction or air in them, they will not pump, they are designed to be dropped vertical in an aquaroll filled with 40 litres of water, that is their design brief, they are quite a weak pump but when primed there are some high flow versions that give a good flow and pressure but with air in the pump they just spin at high speed and do nothing. Link to comment Share on other sites More sharing options...
plwsm2000 Posted March 9, 2019 Share Posted March 9, 2019 Although I agree that these pumps need to be full of water to work, it is not correct to say they MUST be vertical or near vertical to work (but it is better if they are). In addition to the normal fresh water tank, I also have a small (20 ltr) drinking water tank that has a submersible pump that sits literally horizontal in the tank. As the tank is fairly small the amount of water "wasted" (or cannot be pumped out) is also quite small, As an aside, if you change your pump, check that the switches are adequately rated. My drinking water tap over the sink has built in microswitch controlling the submersible pump and is only rated at 2A (for a resistive load). The problem is that the pump is an inductive load and gives a much higher current when it starts and so overloads the switch (I am on my third switch in 2 years!) Link to comment Share on other sites More sharing options...
Derek Uzzell Posted March 9, 2019 Share Posted March 9, 2019 Thanks for the clarifiication. I was aware of Whale’s recommendation that - for best performance - their submersible pumps should be vertically positioned in the water reservoir http://www.whalepumps.com/rv/product.aspx?Category_ID=10001&Product_ID=15&FriendlyID=Whale-Submersible-Electric-Pumps but I was doubtful that this was essential with this type of pump provided that the pump’s impeller was fully submerged. The ’stand pump vertically’ recommendation is repeated here http://www.whalepumps.com/rv/siteFiles/resources/docs/resource-library/181.01_v9_0518_db.pdf and advice is also given that "When fully immersed in water submersible pumps are primed and give instant water delivery”. This Truma webpage discusses water pumps https://www.truma.com/uk/en/products/truma-water-systems/guide-water-pumps-for-motor-homes-and-caravans.html but does not mention replacing one type of pump with another and (as you warn) the consequential need to ensure that existing switches and cabling are adequately robust for the replacement pump’s electrical demands. My Hobby motorhome had a SHURflo diaphragm water pump, but the water outlets (taps and shower) had micro-switches that triggered a relay that controlled the pump’s power-supply. When showering it was possible to hear the pump’s integrated pressure switch coming into play as well. Though complex, this was possibly the ’safest’ arrangement as, if the Hobby’s Truma combination heater’s anti-frost valve opened with the water pump turned on at the motorhome’s main control-panel, only the water in the heater would be drained. My Rapido has the same SHURflo pump but this just reacts to the pressure in the water system. If the Rapido’s pump were switched on and the Truma Combi’s anti-frost valve opened, the water tank would be pumped dry. Link to comment Share on other sites More sharing options...
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