Tricky water pump issue (Mrs Fusion in disgrace) I have to suck on the bathroom tap to get the system to prime, so any ideas anyone??

[MR. FUSION]

Somehow Mrs Fusion managed to turn a tap on during the night & left it running, of course eventually the water ran out & the pump when on spinning for 2 or 3 hours. We were parked next to a construction site with a gennie going so I didnt notice the pump was spinning, thinking it was the nearby gennie & construction site noise!!
I put the gas on to heat up the (now slightly empty) hot water tank, but had luckily forgotten to switch the gas back on at the internal switchboard inside the Carado, so I assume the Truma unit just stayed in no gas fault mode for an hour, whilst it was switched on. Anyway to the fault, the original water pump will no longer prime the water system & neither will the new replacement similar pump I bought!! The only way I can get either pump to prime is to suck on the bathroom tap (nearest to the tank) and then the water will come throygh. I have not emptied the hot water tank since this unfortunate episode as I am not sure if this will fill again, but think it might. The only thing that I can think of that is causing this issue (assuming the new pump is OK) is that the one way valve that sits between the cold water system & the Truma hot water tank has been damaged & is causing an air lock?? Any help appreciated, I would like to not have to suck on the bathroom tap any more

 

[Feltwell]

How full is your cold water tank? When my van had been stood for ages in lockdown, the pump refused to prime until the tank was full, which in my case means the water was almost at the level of the pump itself.

Normally, i.e. when not completely dry (even if I've drained the system as best as I can and it's been sat all winter), it's not so fussy.

 

[PaulOH]

I think you might be answering your own question here! Your read of the situation seems entirely logical (yes captain, it is logical).

My experience of the manually switched 12 volt pump is that it is difficult to over-charge it. When pressure builds, I can hear it labour, so I switch it off.

In your system, with your sleuth detective work, the problem lies in a non-flow of water within the system that isn't cleared until you generate a driver in an area which has less pressure (sink tap sucking). There would definitely appear to be a problem with a non-return valve somewhere!

Next question is where...

 

[Lenny HB]

If your Carado probably has a Reich tandum pump, leaving it running dry for 3 hr has probably burnt out one of the motors. The non return valve may be directly on top of the pump sounds like that could be dodgy as well.

 

[eurajohn]

I had a similar problem recently with my Carthago 142, the pump (Shurflo) is mounted at about the same height as the top of the water tank. After the winter drain down it primed up as normal at first use, then we had a cold spell and I didn't drain down fully just operated the Truma safety valve to drain boiler. Next trip shut valve topped tank up and checked system, all working (or so I thought) first stopover water worked but Mrs. eura said no hot ?? she was right in fact running hot tap the flow eventually dried up, noticed gurgling from boiler - air lock? maybe, anyway try as I may by running taps only made situation worse, took a while but in end I sorted it by taking the supply hose from the top of tank, extending it with a length of hose from my on board just in case supplies, to a length that allowed me to put it in a 10 litre container on the table and then carrying out the same method as you only on the kitchen sink tap, after a while and a top up of the temporary tank all systems go. I'm pretty sure it was the Truma causing problem but no idea what, since then no further problems and all back as intended and working properly.

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[scally]

I first fill mine with the heater bung out until all air is out the shut bung

 

[Rjcamper]

I had the same issue when first took out of storage earlier this year, had to suck on the shower hose to get water through.

Picked up van yesterday, expecting to do the same, no issues and pump primed ok, didn't do anything different????

 

[Otter Spotter]

Wife says ! Just fill your tank with beer, no need to worry how hard you have to suck

 

[hat004]

You could try emptying your tank and then refilling it with the pump off and the sink tap and shower taps open in the mid position in order to prevent an air lock. Then once the tank is full close both taps and switch on the pump to see if it will prime. This has worked for me as previously I to used to have to suck the water through the shower hose in order to get the system to prime.

 

[Stevemoto]

If the pump was running as long as you say it was the impeller May have worn thus losing the seal which would cause cavitation not giving the pump enough pumping pressure until like you say you have to suck it through to relief the weight.
Pumps like that aren’t designed to run long term.

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[dabhand]

Do you have micro switches and are they working as it’s one ( micro switch ) or the other (pump) by the sound of it. If it works when you suck on tap to prime it, Lenny HB ’s answer seems most likely, but I would expect to see a lack of flow at the tap as well. I had the same problem earlier in the year. Put a multimeter on the pump terminals, (set to 12 volts) get someone to turn tap on, if you get 12 volts and nothing happens it’s almost certainly the pump, if you get 12 volts and little flow it’s one side of the pump and it will almost certainly pack in in the near future, if you don’t get 12 volts it’s probably the microswitch, that’s what I did anyway, new pump fitted and then no problem.

 

[Plumb]

If your Carado probably has a Reich tandum pump, leaving it running dry for 3 hr has probably burnt out one of the motors. The non return valve may be directly on top of the pump sounds like that could be dodgy as well.

Non return valve sounds favourite it keeps pump primed

 

[minesapint]

Somehow Mrs Fusion managed to turn a tap on during the night & left it running, of course eventually the water ran out & the pump when on spinning for 2 or 3 hours. We were parked next to a construction site with a gennie going so I didnt notice the pump was spinning, thinking it was the nearby gennie & construction site noise!!
I put the gas on to heat up the (now slightly empty) hot water tank, but had luckily forgotten to switch the gas back on at the internal switchboard inside the Carado, so I assume the Truma unit just stayed in no gas fault mode for an hour, whilst it was switched on. Anyway to the fault, the original water pump will no longer prime the water system & neither will the new replacement similar pump I bought!! The only way I can get either pump to prime is to suck on the bathroom tap (nearest to the tank) and then the water will come throygh. I have not emptied the hot water tank since this unfortunate episode as I am not sure if this will fill again, but think it might. The only thing that I can think of that is causing this issue (assuming the new pump is OK) is that the one way valve that sits between the cold water system & the Truma hot water tank has been damaged & is causing an air lock?? Any help appreciated, I would like to not have to suck on the bathroom tap any more

That sounds like a noisy camp site, did you complain to the owners.
It is a fair bet the pump has burnt out of has damaged the diaphragm or rotor depending on which type you have.
Best of luck with it.

 

[Captain Yoghurtpot]

I first fill mine with the heater bung out until all air is out the shut bung

Thats a good idea, getting it all flowing to all taps and flushing the boiler to boot, then putting the stops in.
Will try this next drain down and start up.

 

[BouncyBoatFolk]

NRV, almost certainly. You've access to the pump, pull the feeder pipe on the top of the pump off, below the NRV, run the pump, MAKING sure the bit of pipe left on the pump is pointing into the water tank, [ the pump kicks water out at a fair old rate, and it can go everywhere another T shirt I own] doing so should tell if the pumps working OK. Did you have to remove the NRV when changing the pump? Is the NRV back on the right way round?
Mike.

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[PaulOH]

Has anyone tried to combine a foot activated pressure system with an electric pump?

I prefer not to use my (quite noisy & now rather old) pump as it needs switched on manually from above the front door (great when you're soaping up your hair in the shower and run out of pressure to rinse!!). Plus it makes a horrendous, 'I'm going to break' noise - like a car that really needs to change down a gear - when it runs for more than about 40-50seconds, so I've got round using it - I think that without solar, it has also helped us stay without EHU on a single battery for more than 3 days.

I would love to give a couple of pumps to a pedal if i want water to rinse an apple or flush the loo rather than running the electric pump!

 

[MR. FUSION]

Thanks to everyone who replied. My pump is the reich type (pictured) if I am correct, from reading some of the replies it has the NRV or similar in the pump unit itself ? If that is the case I could not replace it with a like for like at pump at present & tried another 12v plain pump, but that of course will not work either or works the same as the broken Reich one as the plain pump has no NRV in it. I got the impression from reading on the internet the NRV for this pump was somewhere between the cold water inlet feeding the cold tap system & Truma hot water tank. I envisaged having to remove the whole garage back to get at this sepetate NRV, but if its in the pump unit, this should be a simple job of exchanging the pump unit, unless there are two NRVs ?

 

[Plumb]

Thanks to everyone who replied. My pump is the reich type (pictured) if I am correct, from reading some of the replies it has the NRV or similar in the pump unit itself ? If that is the case I could not replace it with a like for like at pump at present & tried another 12v plain pump, but that of course will not work either or works the same as the broken Reich one as the plain pump has no NRV in it. I got the impression from reading on the internet the NRV for this pump was somewhere between the cold water inlet feeding the cold tap system & Truma hot water tank. I envisaged having to remove the whole garage back to get at this sepetate NRV, but if its in the pump unit, this should be a simple job of exchanging the pump unit, unless there are two NRVs ? View attachment 624496

Well the NRV is normally attached to the pump outlet directly or somewhere where in your photo the white section of hose is , presumably the pump runs and works ok when primed by your suction ?

 

[MR. FUSION]

Well the NRV is normally attached to the pump outlet directly or somewhere where in your photo the white section of hose is , presumably the pump runs and works ok when primed by your suction ?

Yes, after sucking the water through it has worked OK. Although I have not emptied the tanks since I managed to get it working. So I dont know if the whole cold/hot system is going to prime if its fully emptied. So you think the valve is between the while & blue pipes ???

 

[Plumb]

Yes, after sucking the water through it has worked OK. Although I have not emptied the tanks since I managed to get it working. So I dont know if the whole cold/hot system is going to prime if its fully emptied. So you think the valve is between the while & blue pipes ???

Yes that’s where you would normally find the valve but it’s not their! You would see it if it was, yes the valve stops water running back into the tank from your pipe work connected to the taps and shower.

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[BouncyBoatFolk]

Hello, please see the photo of my identical pump, the NRV. In my case the NRV attaches directly to the top of the pump. Your's should be fairly local to the pump and tank.
Have you tried as suggested and removed the white hose just to test the pump itself? That will give you a starting point.
If you need to buy one, seasoned campaigners would say, get a pair.
Mike.

 

[dalspa]

You should be able to check if the pumps have a nrv built in by standing them upright and pouring a little water in the top (where the white tube is fitted). If water runs through then no nrv is fitted, or is not seating properly. It could be that the original pump sucked up a bit of grit from the bottom of the tank and this then stuck in the nrv thereby keeping it open. The nrv valve in the replacement pump could be faulty. However, you say that once primed (by sucking) it works ok - is this so until the tank is drained down, or for a short time when you want to run a tap again? If so, then this would suggest the nrv is the problem.
We have a twin Reich pump in our Hymer and after some years use the water had to be repeatedly primed so I fitted an inline nrv immediately above the pump (about where your white pipe is) which cured the problem. If you had a nrv in the line then you would easily notice it as it would appear as a “bulge” in the pipe work. I suspect yours is in the pump. I assume that, when replacing the pump, it was wired up the right way round. I think it is more an impeller fault.

Edit. BouncyBoatFolk posted while I was typing (I’m a slow typer!). The photo showed a neat nrv where I described- haven’t seen one like that. Incidentally, I always remove my pump and nrv when I drain down in the winter so that any water in the pipe runs back into the tank.

 

[Landy Andy]

You could just fit a new NRV directly on the top of the pump, as the other photo.

 

[BouncyBoatFolk]

Is the water tank under the bench seat? Seeing it was a Carado I assume so, as it was made on the same production line as our Sunlight.
Mike.

 

[MR. FUSION]

Hello, please see the photo of my identical pump, the NRV. In my case the NRV attaches directly to the top of the pump. Your's should be fairly local to the pump and tank.
Have you tried as suggested and removed the white hose just to test the pump itself? That will give you a starting point.
If you need to buy one, seasoned campaigners would say, get a pair.
Mike.View attachment 624524

Thanks for posting that, v.helpful, mine has the tank under the bench seat also. now I know what to look for. Mine (as far as I can tell) has a simple connection joint in the outlet pipe. So the NRV must be elsewhere, which I am betting is not very accessible, like behind the garage !! I will have to get some small jubilee clips to do further testing as I am not keen to re-use the existing clips.

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[MR. FUSION]

Thanks for posting that, v.helpful, mine has the tank under the bench seat also. now I know what to look for. Mine (as far as I can tell) has a simple connection joint in the outlet pipe. So the NRV must be elsewhere, which I am betting is not very accessible, like behind the garage !! I will have to get some small jubilee clips to do further testing as I am not keen to re-use the existing clips.

 

[MR. FUSION]

You could just fit a new NRV directly on the top of the pump, as the other photo.

I think I need to find the existing one first though ?

 

[MR. FUSION]

You should be able to check if the pumps have a nrv built in by standing them upright and pouring a little water in the top (where the white tube is fitted). If water runs through then no nrv is fitted, or is not seating properly. It could be that the original pump sucked up a bit of grit from the bottom of the tank and this then stuck in the nrv thereby keeping it open. The nrv valve in the replacement pump could be faulty. However, you say that once primed (by sucking) it works ok - is this so until the tank is drained down, or for a short time when you want to run a tap again? If so, then this would suggest the nrv is the problem.
We have a twin Reich pump in our Hymer and after some years use the water had to be repeatedly primed so I fitted an inline nrv immediately above the pump (about where your white pipe is) which cured the problem. If you had a nrv in the line then you would easily notice it as it would appear as a “bulge” in the pipe work. I suspect yours is in the pump. I assume that, when replacing the pump, it was wired up the right way round. I think it is more an impeller fault.

Edit. BouncyBoatFolk posted while I was typing (I’m a slow typer!). The photo showed a neat nrv where I described- haven’t seen one like that. Incidentally, I always remove my pump and nrv when I drain down in the winter so that any water in the pipe runs back into the tank.

I wilm need to get some jubilee clips, but will check this out, thanks.

 

[MR. FUSION]

That sounds like a noisy camp site, did you complain to the owners.
It is a fair bet the pump has burnt out of has damaged the diaphragm or rotor depending on which type you have.
Best of luck with it.

It was a car park aire, so I cant really, there were major refurbishment works going on.

 

[dalspa]

I think I need to find the existing one first though ?

Not really necessary as having more than one nrv will not cause any problems. Fitting a new one immediately above the pump is the most efficient location. Just remove the correct length of pipe so that the pump still stands upright on the tank floor. Make sure it’s fitted the right way round - they usually have an arrow showing the flow direction.

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