Aquamax Eco failure. Suggestions?

[estanque_koi]

Hello all,
I'm writting on behalf of a friend and member of the AEK (Spanish Koi Keeper's Society).
I guess he might have achieved a world record on sequential pump failure :
four (yes, 4) Oase Aquamax Eco 8000, plus one Oase Aquamax Eco 12000, and finally yet another Oase Aquamax Eco 8000, all of them died sequentially in less than one year, each pump surviving just from 3 weeks to a maximum of 3 months after installation
These pumps have been sent to Oase Germany for inspection, but there is not a single clue so far concerning the reason behind all those sudden failures.
In the maintime he had to solve the logical filtration problems, and became so frustated as to think in gaving up the hobby
Any idea of what might be wrong? Why are these -otherwise presumed reliable, pumps failing?
This is a brief description of his system:
in-ground informal liner pond, max. depth 1'2 meters, around 12000 liters of volume.
He's got a pump fed filter system comprissing a first chamber with static K1 and a second chamber with aerated K1. The pump is located on top of a support (not directly on the bottom), and has got an extra "satellite" intake. The pump it's supporting an hydrostatic pressure of around 1m cause the filter is built on the ground level. Water returns by gravity via a small cascade.
Any help will be most welcome.

[vippymini]

I'd say without knowing why the pumps failed we would all be making unnecessary guesses as to whats the problem. there are a couple that spring to mind though.
1. electrical problem with supply or installation
2. back pressure from filter (static K1)
lets hope Oase get to the bottom of it.

in the meantime i'd get a different make of pump...

[brother of feeeshpond]

I purchased 3 x Eco 12000's just after they came out.
2 were in pond and one was dry mounted on a q/tank. The dry mounted one failed for no obvious reason in about 6 weeks (if I remember correctly), was returned to outlet where they were purchased (they keep a record) and replaced without a quibble.
There was a few posts on here at the time regarding the reliability of the Eco range but I cannot remember when this was.
Suffice to say all 3 have been running ever since without a problem---touches his head as there is no wood available

[Thepondman]

I was recently in my local dealers when an oase rep was in there, the dealer and the rep was having a chat about returns on the eco range.

He had said since production has gone from Germany to the far east , there has been a number of pumps (ecos) that when out of water running dry , the temperature goes over the running temp and trips the pump! If in water there is not normally this problem.
When discussing this at my koi club with other members quite a few others that have recently had these pumps also had these reoccuring problems, even with the replacement given.
One of the members than spoke to Oase technical who denied anything was wrong!!

[TicToc]

Hi Estanque_ Koi

I have no further suggestions other than those submitted and summised by Questers already. Though there a lot of excellent advisors in the group.

I would however be keen to know how long Oase have had the returned pumps and why they have not responded or maybe they have?

It is feasible that if it isn't a problem with the pumps insitu, as suggested by Vippymini's post. The ones bought and bought again, could be part of a faulty batch and suffering from a build/manufactuers component fault.

I doubt Oase or any pump company would readily admit to this even if it was the case, though I think they would replace them quickly. I have two 16000 ecos that work well as does brotheroffeespond so I hope this offers a little confidence in the brand. Repeatedly touching wood and head at sametime.

Do keep us informed of developments.

Regards
TicToc

[dho]

Max,

Keep touching that head of yours!

If I remember correctly there was a lot of complaints about the eco 8,000 packing in for no reasons at all, also a few eco 12,000. If they swithched the production to the far east (read China) then that would explain it! Never trust a dodgy Chinaman or one from any other nation that you care to mention.

So far I haven't heard any horror stories with eco 16,000s (Max, cover your ears now) or eco 6,000s (I have 2 of them but they are only used occassionally to transfer water!).

David.

[TicToc]

Well there you go Estanque_ Koi.

In no time at all a handful of posts, heresay though it may be reflecting Questers personal opinions; David's endearing words of the Far East and 'Chairmen' (I think he meant to say) from any nation might be the root cause of the Oase pump failure.

DHO - Ears, hair and fingers metaphorically crossed and covered. You strike me as not being to fond of Far Eastern production.

Estanque_ Koi. Do let us know how your Spanish friend gets along with this.

Regards
TicToc

[estanque_koi]

I've been talking to my friend to get more info on his set up and details of the whole issue. The 6 pumps have failed in less than 9 months. Each pump was replaced free of charge by a new one thanks to the Oase's main agent in Spain, even including one Aquamax Eco 12000. They finally offered to pay the money back.
All the pumps were sent to Germany by Oase Spain. The representative told my friend that he was present when one of the pumps was opened in Germany, but there were not any significant findings. He could just add that the pumps stopped for unknown reasons and were definitely dead.
I should point out that my friend had installed two electrical devices: one to limit power on his main supply to 35 Amp, another one to suppress power peaks in the main supply to the pump.
Down here there is a skecht of the pump set up, and there is a possible cause suggested in this thread by wippymini:
could it be due to back pressure?
the pump outlet is PVC flexible pipe of 50 mm (2 inches) that is inseerted in a 90 or 110 mm (my friend was not sure) vertical PVC pipe inside de static K1 chamber that is built above ground level

[vippymini]

right glad you put a diagram. now i can make my point.
when you mount a pump at the bottom of a pond is the "head" measured from the pump to the filter, or is it measured from the point where the pipework breaks the surface to the filter.
if its the latter then what happens as you drain the water level in the pond.... does the "head" increase as the water lowers.....

the way i look at it, even underwater you still have to push the same weight of water up the pipe as you would if the pipe was out of the water....
do you get where i'm coming from??????

[eds]

As far as I understand it 'head' is a combination of static head and frictional head. The static head is the height from the surface of the water to the exit of the pipe (or the highest open point). The frictional head is a function of the length of pipe, diameter of pipe and the type of pipe and bends within it (e.g. reinforced flexible pipe will probably have no sharp bends but may have ribs inside that creat extra resistance so it's a trade-off).

That's my understanding of it anyway.

[vippymini]

eds, thisll throw a spanner in your theory.
if you place a pump with a max head of 6ft in a pond 6ft deep, and it has a rigid pipe of 6ft 2 inches attached. your theory says it would pump as if the head was just 2 inches?????
me says youd get no water out of the pipe at all....

[eds]

Take the frictional head off as you'll lose some from that but you will get a pretty good flow out of that scenario IMHO. When you turn the pump off the water will be at the level of the pond. As the pump is turned on and moves some water into the bottom of the pipe it will push that water already in there up and out of the pipe. It doesn't actually have to move the water 6ft to get any flow out of the top of the pipe.

[boogatee]

does the "head" increase as the water lowers.....

Yes

the way I look at it, even underwater you still have to push the same weight of water up the pipe as you would if the pipe was out of the water....

Not quite ... try lifting your other half while he's standing in a pool and then try lifting him on the deck.... and if he's not too heavy for you to lift whilst standing on the deck ... then I'll volunteer for the experiment

As far as I understand it 'head' is a combination of static head and frictional head. The static head is the height from the surface of the water to the exit of the pipe (or the highest open point). The frictional head is a function of the length of pipe, diameter of pipe and the type of pipe and bends within it .....

That's the way I understand it as well

if you place a pump with a max head of 6ft in a pond 6ft deep, and it has a rigid pipe of 6ft 2 inches attached. your theory says it would pump as if the head was just 2 inches?????

2 inches plus whatever the friction loss was ... as the pump is only beginning to feel the effects of the weight of the water once it’s outside the pond.

[Jagger]

Diego,

Your friends set up is almost identical to mine.My 12,000 Eco is pumping up around 900mm to the filter and turns over around 9,000 litres at that head.There is absolutely no cause here for pump failure in the way he has it set up.

I would concentrate more on the electrical supply particularly the earthing (grounding) of the pump supply wiring and rechecking for power surges and voltage drops.He may need to do more work on stabilising the supply.

It is relatively simple to kill any electrical device if there is a variation in the supplied power or an itermittent fault on the line.

[estanque_koi]

Right. Agree that the static head is the height from the surface of the water to the exit of the pipe (or the highest open point). Then it is not more than 1 meter. So this shouldn't be a problem for the Aquamax.
My friend was a bit worried about the fact of delivering the water from bottom to top via a 110 mm vertical pipe. Although the pressure on the pump, meassured as weight per surface unit, is the same as if all the pipe was 50 mm diameter, the weight of the water column inside the 110 pipe is significantly higher. Could this be a problem for the pump?