Reich Twin Submersible pump (again)

[barbieh]

Hi all,
Reich pumps seem to be a fairly common point of discussion here and I am having to change mine again after less than a year

Van (Burstner Elegance) has tap microswitches with a relay in the control box driving the pump. It has been laid up for some time with water tank dry and the pump struggled to vent all the air on refilling. Water would run from the tap but pehaps not as forcefully as I would have expected. The problem seems that going back 10mins later, there would be air in the pipe again. Removed pump (a real pain of a job) and indeed the non-return valve (NRV) seems to be sticking open/shut until a bang on the table frees it.
New pump ordered.
Water tank looks clean but I can only assume some dirt has been sucked up. Drain plug originally had one of those shiny ball chains which rusted so I removed it a few years ago. I will give the tank a thorough clean before I replace the pump.

Real Question
Measuring across the pump when it is running showed 11.4Volts. This can't be OK can it?
Habitation battery was at 13.8V and I measured 13.8V at the fuse on the output side of the control box. Pump is drawing 2.8A.
Wiring to the pump is ~2M of what I think is 10A Flex - "protected" by a 20A fuse.

Help much appreciated.
Regards,
Reg

 

[Boringfrog]

How long has the pump been 'dry' ? Was it run at all when dry?

 

[barbieh]

Last used in October and tank emptied but wasn't run dry.

Submerged pump in tank and it seems to be pumping strongly.

 

[Boringfrog]

Have you bled all the air out the system, hot and cold side?

 

[tonyidle]

The non-return valve pulls off the pump and is available separately.

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[barbieh]

Did manage to get 2-taps, shower + loo bled using the pump with difficulty but looks like water is running back into tank.

 

[barbieh]

Tony,
It looks like the NRV is permanantly attached to the one I have just removed. Was bought on Oct '19.

 

[David and Sally]

Exactly the same problem. 2019 pump.

Would not run after being left in the winter. It ran a bit but then overheated despite being in the water.

Our pump has two sides to it so if one fails the other still pumps but reduced flow.

Had to replace it.

 

[barbieh]

There does seem to be a common theme on Google of Reich pumps failing after 1 year and possibly after being left dry over winter+lockdown.
Sadly, the pump part seems OK; the NRV probably has grit or something in it. I can suck/blow through it both ways; a bang on the table gets the valve working again for a while.

Does anyone have any idea why the pump has 11.4V across it whilst running. This can't be normal.

 

[Lenny HB]

looks like the NRV is permanantly attached to the one I have just removed. Was bought on

No, they come off similar fitting to Speedfit connectors.

Does anyone have any idea why the pump has 11.4V across it whilst running. This can't be normal.

Quite normal, you are comparing off load voltage with on load voltage. 2.8 amps is a bit low they normally take 4 amps when pumping water.

I got fed up with microswitch taps failing and fitted a Sureflo pressure pump In my Hymer.

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[tonyidle]

Tony,
It looks like the NRV is permanantly attached to the one I have just removed. Was bought on Oct '19.

Are you certain? They're pressed onto a tapered outlet pipe and are incredibly tight.

 

[autorouter]

Measuring across the pump when it is running showed 11.4Volts. This can't be OK can it?
Habitation battery was at 13.8V and I measured 13.8V at the fuse on the output side of the control box. Pump is drawing 2.8A.

On my 2006 Hymer, the pump supply went all the way along the very thin tap microswitch wiring and back, showing about the voltage drop that you describe.

I fitted a relay just next to the pump. The pump supply goes direct to the pump from the relay. The tap microswitches switch the relay coil, which requires far less current. The voltage drop at the pump is now minimal.

 

[barbieh]

Quite normal, you are comparing off load voltage with on load voltage. 2.8 amps is a bit low they normally take 4 amps when pumping water.

That might be consistent with one half of the twin pump giving up the ghost and would explain the lower flow rate. Replacement pump on the way but I dread to think of the voltage loss across that cable at 4A.
There is already a relay in the control box so I might have to run a heavier cable to the pump (not easy).

Are you certain? They're pressed onto a tapered outlet pipe and are incredibly tight.

No, they come off similar fitting to Speedfit connectors.

Well, I can neither twist nor pull it off. Going to have to try wrench on it later ;-) (See above - dead pump)

I thought that I read somewhere that they used to be removeable but Reich introduced a revised design with a fixed NRV (pump is only 1-yr old).

 

[barbieh]

Surprise, surprise, the NRV did come off. So who can please tell me where to buy a replacement?
Although to be fair, the valve seems OK now so the dirt must have dislodged in the drama.

I had to put the NRV in the vice and give it a LOT of twisting to break the seal. There must have been some sort of sealant/adhesive since the fit is only fairly finger-tight now. Not sure I would trust it in tank without re-gluing.

 

[tonyidle]

No, they come off similar fitting to Speedfit connectors.

Some do. My 2008 Hymer pump had one fitted as I described.

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[barbieh]

Some do. My 2008 Hymer pump had one fitted as I described.

It was probably a slightly different pump. Googling, I can see one (without NRV) which has a long spigot which will take the Speedfit connector. The spigot on mine is very short and stepped. Horses for courses.
Thanks for help.

 

[autorouter]

There is already a relay in the control box so I might have to run a heavier cable to the pump (not easy).

Does the supply to the pump flow through the tap microswitches before it reaches the pump?

 

[autorouter]

I dread to think of the voltage loss across that cable at 4A.

The voltage drop along 10 metres of 1.0mm2 cable at 4A is 0.7V. For very thin cable (0.5mm2) the voltage drop is 1.4V.

I don't know what is causing the voltage drop, maybe bad connections, but a heavier cable won't fix it. As I said, I'd first want to eliminate the tap microswitch wiring, which on my motorhome is long and very thin.

 

[Vic. Parsons.]

Our original Hymer pump (same as the Reich) had the NRV welded on with poly pipe or similar. I found this out when I too used a wrench to remove the NRV only to snap the whole thing off. That was fine because the pump was knackered anyway, but i then had to dig out the NRV to remove the pump's tube so that I could re-use the NRV.
I bought a Reich pump and I started off with the old NRV pushed on tight but later on I bought a push fit valve.
A freind also had their pump fail and I had a spare in the van, we tested his old pump wired to 12v in a bucket of water to see how high it would spurt, which wasn't far, and we then tested the new pump which shot water about 7ft up. Whilst doing this, we wired it on the opposite polls and it still worked but not nearly so well.
So, have you checked the polarity of the wires to the pump?
On our Hymer, the live is blue while the brown is neutral, the complete opposite of what you might expect. Wiring it the wrong way will not stop the pump from working, it just wont be as powerful and perhaps over time this might damage the pump.
Our Reich pump has managed 4 years of trouble free use so far.
Below is our spare with push fit NRV.

 

[barbieh]

Does the supply to the pump flow through the tap microswitches before it reaches the pump?

The voltage drop along 10 metres of 1.0mm2 cable at 4A is 0.7V. For very thin cable (0.5mm2) the voltage drop is 1.4V.

I don't know what is causing the voltage drop, maybe bad connections, but a heavier cable won't fix it. As I said, I'd first want to eliminate the tap microswitch wiring, which on my motorhome is long and very thin.

As I said, there is a relay in the control box. The thin wire from the taps only drive a very small current to operate the relay coil. The high current only comes from the relay contacts to the pump via the 2M of cable.
Thanks for voltage drop figures; there must be some additional resistance in either the relay contacts or the short'ish cable. I will try to measure the resistance later.

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[barbieh]

Vic....
Thanks for photo; that explains niceley what others pumps are like. Ours (below) had integral NRV and a push-on/locking nut fitting. This is inside the tank (at the back) and feeds up to a right/angle connector with locknut above the tank in the 1.5" gap below the floor. Nightmare.

I have read on here about the "Hymer wiring trick". Buerstner do it the other way with brown +ve to match the brown +ve on the pump.

 

[tonyidle]

It was probably a slightly different pump. Googling, I can see one (without NRV) which has a long spigot which will take the Speedfit connector. The spigot on mine is very short and stepped. Horses for courses.
Thanks for help.

You're correct. Mine had a much longer and slightly tapered outlet.

 

[Vic. Parsons.]

If you are still getting back-feed into the tank, it may not be the NRV. On ours, the nut that is supposed to hold the hose tight to the NRV does not work with the braided hose we have, the hole in the nut is too large and doesn't actually compress the hose onto the spigot. I gave up on it because the pump kept coming off the hose after a drop off in pressure at the taps. I now have a stainless steel jubilee clip holding it on securely.

 

[barbieh]

If you are still getting back-feed into the tank, it may not be the NRV. On ours, the nut that is supposed to hold the hose tight to the NRV does not work with the braided hose we have, the hole in the nut is too large and doesn't actually compress the hose onto the spigot. I gave up on it because the pump kept coming off the hose after a drop off in pressure at the taps. I now have a stainless steel jubilee clip holding it on securely.

Our NRV was behaving badly when I first removed the pump in that I could blow/suck through it. After banging it and the trauma of removal, the NRV is behaving.
I have a new pump on order which I will fit and clean tank very thoroughly.
If the old pump is working as well as the new one, I will glue NRV on again and use as a spare.

 

[barbieh]

The voltage drop along 10 metres of 1.0mm2 cable at 4A is 0.7V. For very thin cable (0.5mm2) the voltage drop is 1.4V.

I don't know what is causing the voltage drop, maybe bad connections, ........................

Well, it certainly looks like there is a high resistance somewhere. I looped the pump end of the cable and it measured 4.8Ω from output fuse to earth (i.e. to pump and back which is approx 4M of 1.0mm2 cable).
I had to open a tap to get the relay to switch so those contacts are also in series with the cable AFTER the fuse.

Question is, is it the cable or the relay contact?

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[barbieh]

New pump arrived and fitted with MUCH difficulty and seems to be working fine so probably a stuck NRV. Interestingly enough the new pump has a coarse plastic sieve input filter fitted which the old (1year only) one did not. There was some debris in the tank which I flushed out and gave it a clean.

As for the new pump, the motor measures 2.4Ω (1.2Ω the old one) but draws about the same current (2.7A)
There is still only 11.3V across the pump when it is running though. Leave well alone for now I think.

Cheers all for your help.