Water pump intermittently running.

Jun 23, 2019
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Our Whale water pump which is connected to a Truma Combi water heater is intermittently running. It stays on for 10 seconds then off for 1 second and repeats this. The green run light on control panel mirrors this. I can't see any leeks and not losing water. All taps and shower run great and water is nice and hot. We are currently on a site and having to switch pump off at panel to stop over running of pump. I've drained and refilled system several times thinking it may bean air lock as this is first trip since last September. I thought it may be the Truma ultraflow smart switch so have fitted a new one today however the problem still exists. This is on a Bailey Pursuit 430/4 2017 model. Any suggestions welcome.
 
Nov 16, 2015
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Have a look at the pump to tube connection, if this leaks back into the aqua roll the Smart switch does not pick up the pressure and cut off the power to the pump. You might need to put a tywrap around the pipe.
This is all from memory, so I hope it helps.
When we go onto a non hook,up site, it takes maybe 5 minutes for the system to recognise the voltage and pressures. An over complicated system.
 
Jun 23, 2019
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Have a look at the pump to tube connection, if this leaks back into the aqua roll the Smart switch does not pick up the pressure and cut off the power to the pump. You might need to put a tywrap around the pipe.
This is all from memory, so I hope it helps.
When we go onto a non hook,up site, it takes maybe 5 minutes for the system to recognise the voltage and pressures. An over complicated system.
Thanks Hutch. Just tried the pump in in a bucket of water with pump just submerged so I could see. All seems good, no leaks etc. Someone has suggested checking in line valves so will look at them when back home.
 
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May 24, 2014
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With it being a whale system, do you have an inline whale pressure switch. If so, this could need adjusting. Very simple to do. Pdf available from Whale or plenty of videos online.
 
Mar 14, 2005
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The symptoms you describe very strongly suggest two things to me.

The first is the pump finding it hard to reach the turn off pressure, that's why it running for 10 seconds. and second thing is you do have a leak somewhere which is dropping the pressure and causing the pump to run. If you have an adjustable pressure switch it will certainly help to reduce the setting a little.

If you have not found any obvious leaks, then it suggests it could be a non return valve between the pump and the pressure switch that leaking. If its not sealing properly as soon as the pump turns off, the NRV allows a small amount of water back through the valve and down the inside of the hose (so you won't see it) dropping the pressure in the system and turning teh pump back on.

It may be worth investigating the NRV and cleaning it or replacing it.
 
Jul 18, 2017
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Not sure which version of the Whale pump you have, but in our caravan behind the inlet you can calibrate it to stop it running intermittently.
 
Jun 23, 2019
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Hello Everyone. Well I finally fettled the fault. Turned out to be the Truma Compact Housing (the fitting that your water pump plugs into) It has a washer and spring inside it which works as a non return valve. If its not fulling sealing the inlet then the pressure reduces causing the Smart sensor to switch the pump back on. As usual it was the last thing I tried.

I changed the:-
Truma Smart Sensor
Non Return valve
Whale water pump and finally the Compact housing. Certainly a learning lesson! At least I have a few spare parts now as these things always go wrong when on site when you need them and often miles from a dealer who often is out of stock ! WIN_20210427_17_03_21_Pro.jpg
 
Nov 16, 2015
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Nick, thanks for getting back to us with the fix, can the spring and washer be replaced, or is it a complete unit. ?
 
May 2, 2021
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Hi there, I'm new to this forumso here goes.

We have a water pump oscillating problem with our 2015 Coachman VIP 520/4 that we've never seen before during the six years we've owned the caravan until now. The problem started this week when we arrived on site and I connected up the water system. After filling the system and opening the taps to expel the air we noticed the the pump started switching on and off about every 5 seconds. This oscillating is accomaned by a sloshing noise in the the pipework. The system comprises a Truma ultraflow pump and a Truma ultraflow pressure smart switch that is non-adjustable. Has anybody got any ideas about what the problem might be.
 
Mar 14, 2005
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Hello JMacG
Welcome to the forum.

Thank you for teh pretty detailed set of symptoms, and there are some clues in there which might explain your problem.

The first point is the pump is switching about every 5 seconds. This suggests that there is leak somewhere on the pressurised system. The pump generates enough pressure to make teh switch turn off, but the pressure should be locked in the pipe work. If there is a leak the pressure drops back which turns the pump back on etc.

I assume you have looked for any leaks at taps or pipe work fittings, but just in case look again. obviously if you find one it will need fixing. But there is another potential failure point that you won't see. and that's the water systems non return valve between the pump and the pressure switch. If this is not sealing correctly it will release the pressure back into the water barrel through the pump hose - invisible to the naked eye.

I'm not familiar enough with the Truma system to know if it can be easily opened up and inspected, but if it can them you might find seal has been damaged of blocked by some debris.

Alternatively you could fit a second NRV (any make) in series with the original after the pump but before the pressure switch. to see if that corrects the problem.

It is known that some NRV's can be damaged if there is any water left in the system and it freezes.
 
May 2, 2021
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Hi Prof, thanks for your reply. I'll do some more investigation, using your suggestions, and get back to you.
 
Nov 11, 2009
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Hi Prof, thanks for your reply. I'll do some more investigation, using your suggestions, and get back to you.
If you search someone within the last month had a not dissimilar problem and has pictures showing how it was fixed.
 
May 2, 2021
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Otherclive - yes, you're right, sounds a lot like my problem. I'm wondering if the sloshing noise I can hear when the pump switches on and off is water moving backwards and forwards in the pipework, i. e. the NRV isn't working properly . Also, I've re-checked the connections outside the van and have noticed a small leak from the Truma filter housing, adjacent to the pump connection, that is used to connect a hand spray to wash dogs and boots etc. So tomorrow I'm off to the caravan spares shop to get a new NRV and pump and hope that will solve the problem. The pump has become quite noisy over the last couple of days so it may be on the way out.
 
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May 2, 2021
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Hi guys - the day got off to a bad start when the pump failed this morning.

I've now changed the pump, pressure switch and non-return valve but to no avail. We still have the original problem of the pump turning on and off. I've also checked for leaks and there are none that I can see. The drain valves under the van are both closed and again do not appear to be leaking. I was wondering if it could be an issue with the boiler? We still have the sound of sloshing water in the pipework whilst the pump is switching on and off.
 
Nov 11, 2009
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Hi guys - the day got off to a bad start when the pump failed this morning.

I've now changed the pump, pressure switch and non-return valve but to no avail. We still have the original problem of the pump turning on and off. I've also checked for leaks and there are none that I can see. The drain valves under the van are both closed and again do not appear to be leaking. I was wondering if it could be an issue with the boiler? We still have the sound of sloshing water in the pipework whilst the pump is switching on and off.
An obvious question but did you set/ adjust the pressure switch?
 
Mar 14, 2005
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I'm sorry to read your still having problems.

Have you fixed the leak in the external fitting, becasue that certainly would drop the water pressure causing the pump to cycle.

The sloshing sound does suggest their may be an air lock, but I'd have thought by now you would have got rid of that with using it. Some systems do have a surge damper which is like an upturned bottle connected near the water inlet. Its job is to even out the pressure in the cold and hot systems, to prevent alternate surges of hot and warm water when showering. This is designed to trap some air which acts as an air spring accumulator for the cold water. It could be the source of the sound - it s doing its job.

Thanks for telling us about the drain valves.

I doubt its the heater as that is essentially just a tank with input and output pipes. Unless the heaters tank has failed. I'm not sufficiently familiar with teh Combi to know how an internal water leak can be checked for.

I'm sorry but all points to a leak somewhere.
 
May 2, 2021
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It's a Truma Ultraflow smart switch which, as far as cam see, is non-adjustable i. e. There doesn't appear to be any external adjustment.
 
May 2, 2021
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I fixed the leak on the external shower connector. The two 'O' rings looked dry so I smeared some vegetable oil on them and now there is no leak. I don't think we have a surge damper, just a pressure switch. The Truma handbook does show this device but I can't see it in the pipework.
 
Nov 16, 2015
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JMacG, the Truma Surge damper and pressure switch is adjustable. And a new one is adjusted to max as New. 1620074356716-1736740105.jpg
1620074409798-173152553.jpg
 
May 2, 2021
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Hi Hutch - the surge damper is described as an accessory in our Truma manual and is something we don't have fitted. Our system just has a Truma Ultraflow Smart Pressure Switch which appears non- adjustable.
 

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