# 709F possible pump problem?



## strange-fish (May 17, 2011)

Hello, I am a newbie on here and not very technical so.... we have a 709F (which we love) but on our last trip out we starting experiencing problems with the water, initially the hot water would fill but no water would come out of the taps, you could hear it filling but it seemed also to be taking in air. Cold was working ok but we ran out of water rather quicker that we expected. On our return on turning on the main pump switch on the board it immediately starts pumping even though no taps turned on and starts to fill the boiler - you can hear the water gurgling, to the point that it begins to overflow, but no water either hot or cold from the taps. The other half reckoned he could hear air being taken in via the drain but it was shut off and no water was coming out? Any suggestions gratefully followed!!


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## rayrecrok (Nov 21, 2008)

Hi.

It sounds like your pump has rolled over and died, a common fault in all motor homes they are quite cheap and easy to fit a replacement..

Just look for the make and part number, do search on line and pick the nearest to where you live to pick one up or get one sent through the post..

Don't panic! we all have this problem sometime. me twice :roll: ..

Ray.


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## rayc (Jun 3, 2008)

strange-fish said:


> Hello, I am a newbie on here and not very technical so.... we have a 709F (which we love) but on our last trip out we starting experiencing problems with the water, initially the hot water would fill but no water would come out of the taps, you could hear it filling but it seemed also to be taking in air. Cold was working ok but we ran out of water rather quicker that we expected. On our return on turning on the main pump switch on the board it immediately starts pumping even though no taps turned on and starts to fill the boiler - you can hear the water gurgling, to the point that it begins to overflow, but no water either hot or cold from the taps. The other half reckoned he could hear air being taken in via the drain but it was shut off and no water was coming out? Any suggestions gratefully followed!!


It is always difficult to analyze these things remotely especially when the symptoms change i.e. cold water was ok but not now. When you say it begins to overflow where is this from? I assume you have a Truma Combi, is it from the pressure relief valve which has opened thus venting the water out of the relief valve hose rather than allowing it to the taps? 
Can you confirm the boiler make / model?


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## PeteandMe (Sep 19, 2010)

If you feel that you have used more water than you would normally do it could be that the drain for the boiler has opened. Temperatures have been on the low side so the boiler drain has opened to safeguard the boiler. You say that you can hear it filling the boiler. It should already be full if in constant use, save for the water leaking or being dumped by the safety valve.


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## strange-fish (May 17, 2011)

Hi, the boiler is a Truma BS 10/BS 14 - only runs the hot water - no heating. When you say the pressure relief valve - where the hot pipe comes out of the tank there is also a clear plastic tube just pushed on,which disappears underneath somewhere I assume that is what you mean. Yes, it would be coming out of there but it is actually leaking from the point the pipe enters the tank! - it must need tightening, it was running down the outside of the tank!


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## strange-fish (May 17, 2011)

Have just been checking things again - opened all taps to hot and turned on switch on main board - pump set off - boiler filling but it is definitely sucking in air via the water tank drain under the van, even though this is switched to off position. Could it be as simple as replacing the drain valve inside the van?


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## rayc (Jun 3, 2008)

strange-fish said:


> Have just been checking things again - opened all taps to hot and turned on switch on main board - pump set off - boiler filling but it is definitely sucking in air via the water tank drain under the van, even though this is switched to off position. Could it be as simple as replacing the drain valve inside the van?


The question is; If the drain valve is faulty, or open, when the pump starts why is water from the tank not pumped straight out of it? 
Perhaps you have to start with ray [rayrecrok] and suspect the pump. When the pump is pumping water again then is the time to find out why the boiler is not filling / supplying water to the hot taps.


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## strange-fish (May 17, 2011)

Many thanks everyone, will go back to the pump


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## Coulstock (Sep 2, 2008)

Ok - lets get back to basics, I've had a 2004 741f since 2008 so I think I know a bit about Rapidos:

1. Do you have Schreiber or CBE electronics -do you have a Control Panel above your access door like the piccie below ??

2. I've read the 709f spec (theres a 2004 one on sale at Meridian Hayling Island) - your Truma boiler (which should have a pt number something like C6002 or C6004 should provide ducted hot air in addition to hot water .

3. All your parts should be underneath the fixed bed -is that correct -this should include the water pump which should be a SHUREFLO - is that correct 

4 If you switch Power On (at the control panel) and the pump runs ( bump-bump- bump) with the taps OFF and doesn't 'slow down' to stop after a minute or so then the either the pump is knackered ie its not building up pressure OR the pressure switch (part of the pump assy) isn't switching off when the pump reaches 2 BAR thereby switching OFF the 12v supply to the pump.

Harry


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## rayc (Jun 3, 2008)

Coulstock said:


> Ok - lets get back to basics, I've had a 2004 741f since 2008 so I think I know a bit about Rapidos:
> 
> 1. Do you have Schreiber or CBE electronics -do you have a Control Panel above your access door like the piccie below ??
> 
> ...


Hary, The OP has said he has a Truma BS 10/BS 14 - only runs the hot water - no heating.
I was surprised as this is more of a UK build design.
Ray


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## Coulstock (Sep 2, 2008)

My comments on the Truma capabilites were based on the spec posted by Meridian for their 2004 709 f ie hot water and ducted hot air - just like mine but I've also got the 'EH' option of 240 v water heater 

I think we're angling towards water pump problems but we need to determine if there are any problems with the water filter ( part of the pump assy) which, if blocked, could give the symptoms and in the case of SHUREFLO is easily cleaned ( well it is on mine and SHUREFLO manual recommends cleaning it one a year)

Harry


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## PeteandMe (Sep 19, 2010)

If the drain valve is on the suction side of the pump and it is faulty, then air will be drawn into the system. It won't always show as a leak. Would be inclined to exercise the valve before pulling things apart.


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## rayc (Jun 3, 2008)

PeteandMe said:


> If the drain valve is on the suction side of the pump and it is faulty, then air will be drawn into the system. It won't always show as a leak. Would be inclined to exercise the valve before pulling things apart.


Can the drain valve be on the suction side of the pump? I thought it had to be on the output of the pump after the non return valve. How would the boiler drain down if it had to get back through the non return valve to do so?
Here is the Truma installation drawing:
http://www.truma.com/tr/tr/water-comfort/boiler-b-10-b-14.php


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## josieb (Jan 20, 2008)

sounds like the drain valve for the fresh water tank is sucking in air as it's not seated properly. Try spinning the valve handle round and pressing it down to reseal. Try this first as it's quite a common problem, you should hear a click when the valve reseats properly. (you might need to press harder than you think)


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## Coulstock (Sep 2, 2008)

In my Rapido there are 2 dump valves

1. The fresh water dump valve which drains the water from the fresh water tank . It is simply that and is in no way connected to the pump . When the fresh water tank is empty then the pump rate increases to a higher frequency as it draws air not water from the tank.

2. The ( thermostatically controlled ) Truma dump valve. If it is not seated correctly then, when the pump runs , (if there is water in the fresh tank) water will be pumped ( at a normal rate) out of this outlet. If it is not seated correctly then water drains out of this outlet normally, emptying the boiler , pump running or not. I keep a clothes peg on mine to stop it tripping in 'cool ' weather ie < 4 C- keep in mind it won't reset until ambient temp is > 8 C.

Pity 'strange-fish' hasn't answered my earlier questions

Harry


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## PeteandMe (Sep 19, 2010)

No way of telling where the drain valve one way valve and pump is positioned in relation to the tank and taps. Drawing is what is Trauma suggest. Later drawing also shows an optional extra a frost protection valve which would allow draining of the boiler.


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## strange-fish (May 17, 2011)

Coulstock said:


> Ok - lets get back to basics, I've had a 2004 741f since 2008 so I think I know a bit about Rapidos:
> 
> 1. Do you have Schreiber or CBE electronics -do you have a Control Panel above your access door like the piccie below ??
> 
> ...


Sorry not to have answered your questions - it was not intentional - just had not had time till now. Also ran out of posts - so am now subscribed !!
1. Similar but not quite the same
2. Boiler only does water not hot air. 
3. Yes, under bed and shurflo.
4. Yes it does run and continue to do so.

But there is definitely air being sucked in from the drain pipe for the main tank as you can feel it when pump is on if you put your finger on the end of the pipe under the van!


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## PeteandMe (Sep 19, 2010)

So it sounds like a faulty tank drain valve. Would try moving from on to off a few times. Seal is dirty or seal has failed.


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## rayc (Jun 3, 2008)

strange-fish said:


> Coulstock said:
> 
> 
> > Ok - lets get back to basics, I've had a 2004 741f since 2008 so I think I know a bit about Rapidos:
> ...


I wonder why the pump is pulling up air from the drain? With the fresh water tank full you would think that the weight of the water would prevent that especially as when water is drawn off there should be an inlet at high level to let air in to replace the water.


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## josieb (Jan 20, 2008)

Simplified It's because when the valve is not seated correctly there is no vacuum and so it causes it to suck in air. once seated right it is sealed. Can expand if necessary ! But I'm sure one of the experts out there will! This is quite a common fault and mainly occurs after the valve has been left in an up position after draining and sometimes needs a bit if brute to seat it correctly, I think that's why some think something major has gone wrong when it's not always the case.

I'm not saying that it is the case in this instance, but as it sounds like it, its the first place one should always look.


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## strange-fish (May 17, 2011)

The valve is definitely not working correctly but having closed it down and checked the filter on the pump is clear, the pump is still coming on as soon as I turn the water switch on the wall on and not pumping any water. Plus even though the taps are all off it appears to be trying to fill the hot tank!
So new valve first and then further pump investigation I think. But as I am away for a few days will now have to wait until next week!


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## rayc (Jun 3, 2008)

strange-fish said:


> The valve is definitely not working correctly but having closed it down and checked the filter on the pump is clear, the pump is still coming on as soon as I turn the water switch on the wall on and not pumping any water. Plus even though the taps are all off it appears to be trying to fill the hot tank!
> So new valve first and then further pump investigation I think. But as I am away for a few days will now have to wait until next week!


If it is a pressure system, as opposed to microswitches on the taps, then that it what it will try to do. It wll get to a state where the air in the boiler stops any more water entering it as no hot tap is open to let the air escape.
Not sure what you mean by "the pump is still coming on as soon as I turn the water switch on the wall on and not pumping any water. Plus even though the taps are all off it appears to be trying to fill the hot tank!" Those two things seem to contradict each other :?


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## Coulstock (Sep 2, 2008)

The Rapido fresh water system works on 2 BAR being maintained in the pipework and if this pressure drops ( e.g opening a hot or cold tap) then the pressure switch on the SHUREFLO pump closes and 12v is switched to the pump which runs until pressure is returned to 2 BAR

Reading 'strange-fish' most recent comments: 

"the pump is still coming on as soon as I turn the water switch on the wall on and not pumping any water"

Translating (I think ) this means that as soon as power is applied (presumably at the CBE control panel) the pump runs without any taps being open . He says the filter is clean and presumably the cold tank has water in it so the pump isn't building up sufficient pressure to open the pressure switch. 

So one more check worth making (and it happened to me) is to unscrew the inspection cap on the fresh water tank (large black screw fit) and physically check the red spigot protruding itno the bottom of the fresh water tank. I had an incident early in my ownership where similar symptoms had resulted from a small piece of tank sealant (like a small sliver of white tank sealant ) had got itself stuck across the intake end of the red spigot stopping the pump drawing water from the tank. So when I pur power on the pump (ie from the control panel) the pump ran (without taps being open) as the pressure in the pipework was not 2 BAR.

Please do not persist with 'problems with the dump valve ' - if its not properly closed then water will run out of it even if power is on it or not ie the definitive check on the dump valve is -DOES IT LEAK. !!

Harry


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## strange-fish (May 17, 2011)

Coulstock said:


> The Rapido fresh water system works on 2 BAR being maintained in the pipework and if this pressure drops ( e.g opening a hot or cold tap) then the pressure switch on the SHUREFLO pump closes and 12v is switched to the pump which runs until pressure is returned to 2 BAR
> 
> Reading 'strange-fish' most recent comments:
> 
> ...


Your translation is correct Harry. Also the dump valve was faulty have sorted that so will check out red spigot thanks.


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## strange-fish (May 17, 2011)

Thanks everyone  
It is now fixed, replaced water drain valve and also hot water feed out which did not have as tight a seal as it should. Which meant pressure was not working as it should. We are now up and running again


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