Truma pump problem

[arkay]

I have had my Lunar Quasar for just over a year and think it is great overall. However, I have a very annoying problem with the pressure switch that is connected in-line with the pump.

Despite constant adjustment it repeatedly pulses when the pump is switched off; i.e. when a tap is turned off. Also the pump sometimes stays on even after the tap is turned off and I have to turn the pump master switch off.

Questions: can the pressure switch be bypassed or disconnected somehow while still allowing the pump to operate? Why do Truma fit this device? - is it to allow the use of mains pressure inlet on 'super' pitches?

It is really frustrating and the dealer has not been very helpful when the van was serviced.

Any advice would be gratefully received!

 

[Damian]

Robert, you do not say how old the van is, or what system you have, as such, is it the the Truma aquaflow or is it just a pressure switch and outboard pump?

The usual suspects for a cycling pump area water leak, incorrectly set switch or faulty switch.

With the pressure switch system you must have one, unfortunately, but it may be able to be changed for a different type.

Unless it is one of the newer type switches, which are supposed to be voltage sensitive, many switches display odd behaviour due to volt drop.

Pressure switch systems are fitted to avoid fitting taps with microswitches and are operated by pressure changes when a tap is opened.

 

[davedee]

Hi Robert.

We had the self same problem with our van (then 8 months old) at the start of a two month holiday in Scotland this year.

It came to light because we did not hear the over-running,resulting in a burned out pump.

We bought a new pump and,despite efforts to adjust the pressure switch, had to bypass it and keep switching the pump on and off at the master switch for the rest of the jollies.What a bind that was!

On return,the dealer fitted and set a new one which is now ok.

The unit was the Truma Ultraflow Surge Damper with Built-in Pressure Switch.

What is it supposed to do? Extract from the manual :

".....the surge damper enables an even water flow in the pressurised water supply.The integrated electronically controlled pressure switch turns the water pump on and off regardless of the momentary atmospheric pressure and battery power(between 10v and 14v)."

Translation : It protects your onboard pipework etc when you're connected directly to mains water as on a super pitch and when you're not,it turns your pump on and off.

When we had the new one fitted under warranty,our dealer set it to cut off six seconds after turning the tap off.Apparently this is the recommended setting.

At a rough guess Robert, I'd say your unit is kapput!

There again mate, it could be a totally different set-up in which case, I'm sorry but I don't know!

Hope this is of some help.

Dave

 

[Chrissylizzie]

Hi Robert

We have a Lunar Quaser 2007 and also find our pressure switch frustrating. We frequently have to adjust it but usually once it settles down it is ok. One thing we have noticed is that it is worse if you turn a tap on for just a few seconds before turning it off again - to wet a toothbrush for example. The longer the tap is on the better it is. Our dealer was not too helpful when first mentioning this to him but if it worsens, we will certainly expect better information.

 

[ProfJohnL]

Hello Dave & Dee,

Your translation is way wrong. The quote you give has no reference to mains water supply presures, and I am certain that if you did attempt to plug your caravan directly onto a mains water supply, you woudl be presented with a flood.

Caravan systems are only rated to 1.5Bar where as mains water can easily reach 6Bar, and more if there is surge pressure in the pipework.

There are systems designed to regulate the pressure down to a safer 1 to 1.2Bar but these are sold specifically for this purpose.

 

[Damian]

Having just returned from putting all the joints back together in a van that suffered a failure of the pressure reducer in the mains water adaptor I can categorically say that van pipework will NOT take mains pressure water.

The owners of the van will also confirm this as they continue to try and dry it out, along with every bit of their equipment within the van.

 

[davedee]

Hi John.

This unit was presented to us as I've stated : the surge damper prevents any surge in water pressure reaching the onboard pipework when coupled to a water supply as on a super pitch.

Obviously the supply pipe from the tap to the van has to be an Ultraflow Waterline or similar.

Dave

 

[ProfJohnL]

Is that English translation printed on the box, or are you quoting from a salesman?

 

[arkay]

A quick update: took the van in to the supplying dealer and he replaced the pressure switch and pump. Said it was working okay. Will try it this weekend on a trip to Banchory. The mechanic said it could well have been a faulty pump impellor producing the pressure problem. He replaced the pressure switchall well just in case.

Will post again next week and let you know if it has been fixed.

 

[arkay]

Just back from Banchory and pleased to report that the pump behaved itself much better. It did flutter a couple of times but bearable. The system doesn't seem to like the pump being on for a second or two so we watch out for that and all has been well.

Thanks for all your helpful comments.

 

[JimC]

I have a 2006 Lunar Lexon EW and the water pressure switch performs fine for most of the time. I must agree with Chrissylizzie that the wetting the toothbrush senario is the same with my van.We also found that its better to turn the tap full on even if only briefly. I also find that if I am not on electric hook up the lower voltage can cause the pump to run continuously and needs adjustment at the pressure switch.

Jim C