Mitsubishi Water Pump

[StraightTalk]

Which model of water pump is nowadays considered most reliable and/or is preferred by country dwellers - the 'good old' WP or the newer CP or IP?

[Lamkyong]

 WP or the newer CP or IP?   sorry please  explain these abbreviations   thanks 

[wayned]

Here's an explanation:https://translate.google.com/translate?hl=en&sl=th&u=http://www.airpumpmart.com/15282631/mitsubishi-wpipepcp-series-&prev=search

 

I've lived here 19 years, have two houses with pumps and have always used the WP series so I have no knowledge of the others.

 

The WP series has a large accumulator tank but there is no internal bladder.  I have had good luck with all of them except ants in the pressure switch - not the pumps fault.  One negative is the quality of the welding on the tanks.  I have had three tank failures where the doubler plates are welded on at the   tank output ports.  They started out as pin hole leaks but got bigger and I either replaced the tank or "fixed" it by welding on a plate on the outside.  Other than that, they have been good pumps.

[KhunBENQ]

IP : inverter pump. Quite expensive, variable/controlled motor speed).

Comparable to the inverter ACs.

I guess it has some advantages (less noise, less power consumption). But how long will it take until that pays off?

 

CP : constant pressure. I have no real idea what the difference to an IP is.

[StraightTalk]

22 hours ago, wayned said:

Here's an explanation:https://translate.google.com/translate?hl=en&sl=th&u=http://www.airpumpmart.com/15282631/mitsubishi-wpipepcp-series-&prev=search

 

I've lived here 19 years, have two houses with pumps and have always used the WP series so I have no knowledge of the others.

 

The WP series has a large accumulator tank but there is no internal bladder.  I have had good luck with all of them except ants in the pressure switch - not the pumps fault.  One negative is the quality of the welding on the tanks.  I have had three tank failures where the doubler plates are welded on at the   tank output ports.  They started out as pin hole leaks but got bigger and I either replaced the tank or "fixed" it by welding on a plate on the outside.  Other than that, they have been good pumps.

Thanks for responding and valuable information link.

I've had and am still having a reasonable good run using the WP model/series. Luckily I don't seem to have an ant problem and after 9 years the tank does not show any weaknesses.

The only (minor) stew I have is that after about 3 to 4 (or so) power outages the pump performance degrades gradually because the tank is replacing the air with water slowly but surely. To restore normal pump operation I simply drain the tank thus removing the water-log.

My wife and I are away at times and replaced the drain plug with a good-quality gate valve to facilitate the pumping restoration for the mil but this can be 'problematic' at times...

I am let to believe that the CP model is not susceptible to any power outages but could not find any evidence or specification written in English to support this claim hence my op to this forum.

I personally am happy to continue with the WP model/series but would reconsider/re-evaluate based on experiences by others. 

[lopburi3]

Quote

I am let to believe that the CP model is not susceptible to any power outages

That would really be amazing.  No power = no water.  What they offer is more consistent pressure/water flow and expect this would still be true for brownouts if pump able to run/not overheat.  But it is not going to operate during a power outage.

 

The pumps I have heard of that type here in Bangkok (not sure of maker) are often very loud and are running anytime water is used.  Although I much appreciate consistent water pressure have found the extra cost of Grundfos pumps to be well worth it if plumbing can handle higher pressures they normally provide.

[StraightTalk]

8 hours ago, lopburi3 said:

"I am let to believe that the CP model is not susceptible to any power outages"

That would really be amazing.  No power = no water.

Yeah, the wording is really stupid - my bad!
I meant to say that the CP model may not susceptible to 'water-logs' when the electricity is restored after a temporary suspension.

[CGW]

On 3/25/2017 at 0:07 PM, KhunBENQ said:

IP : inverter pump. Quite expensive, variable/controlled motor speed).

Comparable to the inverter ACs.

I guess it has some advantages (less noise, less power consumption). But how long will it take until that pays off?

 

CP : constant pressure. I have no real idea what the difference to an IP is.

Advantages of the Inverter are, as you state less power consumption and less noise, ideal if you are running a water sprinkler or the like, pump will run constant at low speed rather than on/off, on/off etc

Constant pressure is just that, pump senses pressure loss and speeds up, like if you turn on another tap when taking a shower.

How long does it take to pay off? probably never, depends what price you put on less noise and continuous pressured water supply! for sure they do use less power!

Personally I reckon on getting four years out of a pump, any problems thereafter I change it, not worth the hassle of fixing, the cost of this is less than one baht a day, not much to have continuous water supply in my opinion.

[sometimewoodworker]

On 24/03/2017 at 6:44 PM, SouthernDelight said:

Which model of water pump is nowadays considered most reliable and/or is preferred by country dwellers - the 'good old' WP or the newer CP or IP?

WP series are well pumps, not recommended for instant hot water showers

CP series are constant pressure pumps recommended for instant hot water showers 

both are good old technology 

 

the new one. Is the IP at about 3 times the price. As it is an inverter it can supply different outlets and combinations outlets at a constant pressure. Because the pump runs at different speeds depending on demand.

[Naam]

56 minutes ago, CGW said:

How long does it take to pay off? probably never, depends what price you put on less noise and continuous pressured water supply! for sure they do use less power!

my comments:

-a low noise inverter pump is the optimal solution for those who have the pump mounted in their living room or bedroom,

-it's cheaper and less repair headache to achieve a balanced water supply by adding a pressure tank of adequate size,

-pumping x-volume of water requires y-consumption of energy. inverter pumps have not yet bypassed the laws of physics even though clever marketing people claim they have.

[StraightTalk]

20 hours ago, sometimewoodworker said:

WP series are well pumps, not recommended for instant hot water showers

CP series are constant pressure pumps recommended for instant hot water showers 

both are good old technology 

 

the new one. Is the IP at about 3 times the price. As it is an inverter it can supply different outlets and combinations outlets at a constant pressure. Because the pump runs at different speeds depending on demand.

AFAIK, in the Mitsubishi camp Model WP=Water Pump. Other pump manufacturers use WP to denote Well Pump, oh well :-)

I use the Mitsubishi model WP for instant hot water showers; In fact I'll have one right now.

[lopburi3]

The problem with using the WP pump is that there is a great deal of difference between full and restart pressure and even at highest most water heaters do not supply good shower flow - perhaps OK if you are used to water saving taps but living outside developed countries most of my life I prefer a bit more water for my showers - which are short - so probably not more total water used.

[StraightTalk]

11 hours ago, lopburi3 said:

The problem with using the WP pump is that there is a great deal of difference between full and restart pressure and even at highest most water heaters do not supply good shower flow - perhaps OK if you are used to water saving taps but living outside developed countries most of my life I prefer a bit more water for my showers - which are short - so probably not more total water used.

I don't share your observation; My Mitsubishi WP pump performs as advertised and does not indicate any noticeable variation of pumping pressure (correct plumbing(s) do make a difference though). And there many brands of water heaters available here in Thailand providing high to very high shower-flow on condition the /right/ pump is installed.  

[sometimewoodworker]

12 hours ago, SouthernDelight said:

AFAIK, in the Mitsubishi camp Model WP=Water Pump. Other pump manufacturers use WP to denote Well Pump, oh well :-)

I use the Mitsubishi model WP for instant hot water showers; In fact I'll have one right now.

Many people use pumps that are not recommended for instant hot water showers for them, often because they didn't know the recommendations beforehand.

 

Do they work, usually. Are they as good, probably not.

[lopburi3]

50 minutes ago, SouthernDelight said:

I don't share your observation; My Mitsubishi WP pump performs as advertised and does not indicate any noticeable variation of pumping pressure (correct plumbing(s) do make a difference though). And there many brands of water heaters available here in Thailand providing high to very high shower-flow on condition the /right/ pump is installed.  

There is a cut in and off for the pressure tank of such pumps, which is quite far apart, and most people will indeed notice the drop in pressure and then pickup when pump starts to fill tank again.   If you lived in the country and used well pumps all your life expect it would not be such an issue - but for people used to water tower source consistent pressure it makes a difference.  And agree there are many water heaters but finding the right one is not easy - most do not want to work as well with well pump pressure as they do with higher pressure - one of the reasons have been using Grundfos pumps for last 15 years or so - after using largest Mitsubishi models for several decades.  And as FYI find the current cheap Panasonic water heaters seem to work better than most previous higher priced units (and currently have 5 brands of heaters in operation).

[StraightTalk]

23 hours ago, sometimewoodworker said:

Many people use pumps that are not recommended for instant hot water showers for them, often because they didn't know the recommendations beforehand.

 

Do they work, usually. Are they as good, probably not.

AFAIC, an independent water heating device does not care how (e.g. from which type of pump) the water is pushed through its heating coil or boiler. Regardless of my gripe relating to water-log (which I don't think is a design flaw of the pump itself) my WP performs as expected. And since I haven't received any convincing argument switching from WP to CP I am for one going to stick with what am satisfied with.

[Pib]

Regarding the WP series and noticing a pressure difference when using a shower/instant heater.  That will only occur if your WP is water logged/not maintaining the proper amount of air in the tank.

 

I have now used a WP-255 pump for 9 years used with two instant heaters and the only time I noticed a pressure different is when the air control/balance valve was defective several years ago causing the pump's tanks to water log itself which causes a pulsating type water flow and very frequent running of the pump with any kind of water flow.    

 

Now the WP255 pump produces a varying pressure between 2.1 bar/30psi to 2.8 bar/40psi for an average pressure of 35psi.   I do not feel or see an pressure variation when talking a shower with instant heater.   But I will admit if you have a WP85, WP105, or WP155 model pump which only put out 1.3bar/19psi to 1.9bar/28psi that in that lower pressure range when using the pump the pressure variation might be felt and the pump on-off cycle be predominately on with "any" water being drawn.

 

By frequently running I mean the pump's on-off cycle when water is being drawn around 80% (or more) on and 20%  off.  It will be more balanced approx 50-50 with a properly functioning pump which requires it's pressure tank to have the proper amount of air in it.

Maintaining the proper amount of air in the tank is accomplished by the air control valve which Mitsubishi calls "AC-ASSY" (air control assembly).  It's that six-sided black valve with one end screwed into the top of the tank and the other end has a pencil diameter sized tube running back into the water intake.  The valve basically consists of a spring, a rubber diaphragm, and two check valves.  One of those check valve (consisting of a small spring, small ball, metal washer, and rubber seal can be removed/checked/cleaned by just unscrewing it from the underside of the valve...just unscrew the cap with the nipple on it and carefully remove the parts....and remember the order they came out in).  

 

But what fails in the air control valve is the "rubber diaphragm" that will develop a pin-hole sized leak which cause the valve to only partially operate which causes the tank to water log after a few days to few weeks after draining the tank to allow air into the tank.   Then you are back to pulsating water flow and the pump running most of the time even with a small flow of water.   I guess a larger rupture would result in water logging much faster....within minutes to hours.  

 

A replacement air control valve costs around Bt700...easy and fast to replace....anyone can do it.   Durn shame a person can't buy just the rubber diaphragm within the valve as that is really the only thing that can fail.  And it really can not be patched due to the special material of the diaphragm...a patch just won't stick long....I've tried.  I guess if you are pumping dirty water the check valves could become clogged but they can be cleaned...or the small pencil diameter hose could become clogged....but the only thing that can really fail in the air control valve is the rubber diaphragm. 

 

Below is a picture of a disassembled air control valve....well, not "fully" disassembled because you can still unscrew the cap with nipple to remove the one check valve (this is where air is sucked in to be fed to the pressure tank)...you cannot remove the other check valve mounted in center of one of the black covers as it's permanently installed at the factory.  

 

I circled the area of the rubber diaphragm that developed the pin-hole size rupture...actually the rubber in the area of the rupture had just got "hard"....was no longer pliable like the rest of the diaphragm.   Tried patching it with RTV rubber and inter-tube tire patch...neither would stick/seal very long....just couldn't stay adhered to the special diaphragm rubber.   Bought a new one....been fine since....no water logging...no pulsating water....can not feel shower with heater pressure variations, etc.   

 

 

 

 

 

[lopburi3]

My experience was with the WP405 models (but as said ended about 15 years ago) - which was there most powerful - but believe pressure was mid 20 PSI with low 30 PSI as highest.  And indeed had several of those bladder failures, and tank failures and other issues.  Also with many BR and kitchen taps there often was more than one tap open and original piping was 1/2" so that did not allow much flow (and being galvanized probably well blocked since built in 1974).

[Pib]

Here's the pressure specs on Mitsubishi WP pumps....like the the WP405 which is 2.4 bar/35 psi  to 2.8bar/41 psi  for an average of 38 psi.  

 

As mentioned earlier there is a very significant difference in pressure ranges for the WP155 and lower model numbers....best to avoid these lower number model if you want better pressure/volume in the shower and elsewhere.

 

 

 

[StraightTalk]

7 hours ago, Pib said:

Regarding the WP series and noticing a pressure difference when using a shower/instant heater.  That will only occur if your WP is water logged/not maintaining the proper amount of air in the tank.

 

I have now used a WP-255 pump for 9 years used with two instant heaters and the only time I noticed a pressure different is when the air control/balance valve was defective several years ago causing the pump's tanks to water log itself which causes a pulsating type water flow and very frequent running of the pump with any kind of water flow.    

 

Now the WP255 pump produces a varying pressure between 2.1 bar/30psi to 2.8 bar/40psi for an average pressure of 35psi.   I do not feel or see an pressure variation when talking a shower with instant heater.   But I will admit if you have a WP85, WP105, or WP155 model pump which only put out 1.3bar/19psi to 1.9bar/28psi that in that lower pressure range when using the pump the pressure variation might be felt and the pump on-off cycle be predominately on with "any" water being drawn.

 

By frequently running I mean the pump's on-off cycle when water is being drawn around 80% (or more) on and 20%  off.  It will be more balanced approx 50-50 with a properly functioning pump which requires it's pressure tank to have the proper amount of air in it.

Maintaining the proper amount of air in the tank is accomplished by the air control valve which Mitsubishi calls "AC-ASSY" (air control assembly).  It's that six-sided black valve with one end screwed into the top of the tank and the other end has a pencil diameter sized tube running back into the water intake.  The valve basically consists of a spring, a rubber diaphragm, and two check valves.  One of those check valve (consisting of a small spring, small ball, metal washer, and rubber seal can be removed/checked/cleaned by just unscrewing it from the underside of the valve...just unscrew the cap with the nipple on it and carefully remove the parts....and remember the order they came out in).  

 

But what fails in the air control valve is the "rubber diaphragm" that will develop a pin-hole sized leak which cause the valve to only partially operate which causes the tank to water log after a few days to few weeks after draining the tank to allow air into the tank.   Then you are back to pulsating water flow and the pump running most of the time even with a small flow of water.   I guess a larger rupture would result in water logging much faster....within minutes to hours.  

 

A replacement air control valve costs around Bt700...easy and fast to replace....anyone can do it.   Durn shame a person can't buy just the rubber diaphragm within the valve as that is really the only thing that can fail.  And it really can not be patched due to the special material of the diaphragm...a patch just won't stick long....I've tried.  I guess if you are pumping dirty water the check valves could become clogged but they can be cleaned...or the small pencil diameter hose could become clogged....but the only thing that can really fail in the air control valve is the rubber diaphragm. 

 

Below is a picture of a disassembled air control valve....well, not "fully" disassembled because you can still unscrew the cap with nipple to remove the one check valve (this is where air is sucked in to be fed to the pressure tank)...you cannot remove the other check valve mounted in center of one of the black covers as it's permanently installed at the factory.  

 

I circled the area of the rubber diaphragm that developed the pin-hole size rupture...actually the rubber in the area of the rupture had just got "hard"....was no longer pliable like the rest of the diaphragm.   Tried patching it with RTV rubber and inter-tube tire patch...neither would stick/seal very long....just couldn't stay adhered to the special diaphragm rubber.   Bought a new one....been fine since....no water logging...no pulsating water....can not feel shower with heater pressure variations, etc.   

 

 

 

 

 

My sincere thanks for composing and sharing this very informative & educational write up!

[StraightTalk]

On 29/03/2017 at 9:34 AM, Pib said:

[cut

Maintaining the proper amount of air in the tank is accomplished by the air control valve which Mitsubishi calls "AC-ASSY" (air control assembly).  It's that six-sided black valve with one end screwed into the top of the tank and the other end has a pencil diameter sized tube running back into the water intake.  The valve basically consists of a spring, a rubber diaphragm, and two check valves.  One of those check valve (consisting of a small spring, small ball, metal washer, and rubber seal can be removed/checked/cleaned by just unscrewing it from the underside of the valve...just unscrew the cap with the nipple on it and carefully remove the parts....and remember the order they came out in).  

 

But what fails in the air control valve is the "rubber diaphragm" that will develop a pin-hole sized leak which cause the valve to only partially operate which causes the tank to water log after a few days to few weeks after draining the tank to allow air into the tank.   Then you are back to pulsating water flow and the pump running most of the time even with a small flow of water.   I guess a larger rupture would result in water logging much faster....within minutes to hours.  

 

A replacement air control valve costs around Bt700...easy and fast to replace....anyone can do it.   Durn shame a person can't buy just the rubber diaphragm within the valve as that is really the only thing that can fail.  And it really can not be patched due to the special material of the diaphragm...a patch just won't stick long....I've tried.  I guess if you are pumping dirty water the check valves could become clogged but they can be cleaned...or the small pencil diameter hose could become clogged....but the only thing that can really fail in the air control valve is the rubber diaphragm. 

 

Below is a picture of a disassembled air control valve....well, not "fully" disassembled because you can still unscrew the cap with nipple to remove the one check valve (this is where air is sucked in to be fed to the pressure tank)...you cannot remove the other check valve mounted in center of one of the black covers as it's permanently installed at the factory.  

 

I circled the area of the rubber diaphragm that developed the pin-hole size rupture...actually the rubber in the area of the rupture had just got "hard"....was no longer pliable like the rest of the diaphragm.   Tried patching it with RTV rubber and inter-tube tire patch...neither would stick/seal very long....just couldn't stay adhered to the special diaphragm rubber.   Bought a new one....been fine since....no water logging...no pulsating water....can not feel shower with heater pressure variations, etc.   

 

 

 

 

 

FYI, I just bought an "AC-ASSY" (air control assembly) MITSUBISHI WP85-405 for THB 450 at Ruang Sang Thai - Buri Ram.

[Pib]

That's good....when I bought mine here in Bangkok it was around Bt700 but I had to buy it from a pricey electric tools store....I didn't do any shopping around...was just too happy to find a store close by my home that had the valve...actually it took them a day to get it in.

 

When installing the valve be careful with the small plastic tube and it's two screw-on fittings on the top of the valve.  DO NOT over tighten.  Just finger tight and then maybe another quarter turn.   It doesn't take much torque to effect a good seal with the connectors and you could break them if using a wrench to tighten down like with a metal fitting.    Also be sure that tube is not clogged....mine was actually clogged on one end one time....it looked like a small piece of PVC tape.  There was no PVC tape on or needed on this fitting...it was probably just junk in the water line....the inside diameter of that small tube is "small" so it wouldn't take much to clog it.

 

Before turning the pump on be sure to "completely" drain it to ensure you start of with the correct water/air mixture in the tank....once you start the pump it will achieve that proper water/air mix in the tank automatically and then the air control valve keeps it that way.   But I still about once or twice a year completely drain the tank just to be draining it and to reset the water/air mixture in case the control valve let it get  a little out of balance.   As you know it only take a minute to drain the tank.

 

Good luck.  And if you take the old valve apart if the two check valves were clean and you can not fine any rupture in the rubber diaphragm (look really, really close as the it just takes a pin-hole size rupture to make the valve not work properly), then something else is causing your tank to waterlog....another leak that is too large for the air control valve to compensate for.

 

 

[StraightTalk]

Thanks for the useful maintenance clues, I'll be guided accordingly.

[kamalabob2]

This Friday morning I spoke at length in English with a technical representative of Mitsubishi Electric. The water pumps he had on display in Buriram seem a step up from water pumps I had seen in Isaan at HomePro or the Buriram Global House. There must be a professional water pump dealer in the OP's province who can offer a better grade of water pump for a home or farm in Thailand. 

[lopburi3]

They indeed seem to have some step up models - there IMCH inverter model seems to sell for 17 and 20k baht.

 

 

 

[Naam]

Pib,

you're da man!

[Tofer]

Has anybody had any experience of 'ARCE' centrifugal pumps. We recently bought one from HomePro, a special offer deal my honorary Yorkshire (Thai) wife could not resist!

 

It's not fixed yet, so I'm guessing I could take it back if Mitsubishi appears a better choice.

 

We're using this to pump from our well to large storage tanks with float switches via filters (any advice on filters would be appreciated also), then a pump for distribution to the buildings outlets, currently a 3-bathroom villa and a 1-bathroom apartment, and potentially 3 more apartments if we feel they are viable.

 

Home Pro appear to recommend whatever is being 'pushed' at the time. We've been recommended 2 different filter products in the space of a couple of months by the same salesman!! Firstly a triple plastic tub arrangement with easily accessible filters, then a larger twin filter unit that looked like an old fashioned paraffin heater casing.

 

We're next to the sea in Koh Lanta Yai, Krabi, so rust deterioration will be an issue also.

 

Wish I'd found this forum sooner!

[Farang99]

I use a pump to supply water for the garden, pumping from the canal behind the house. Our Hitachi has recently failed and am trying to decide what to replace it with. Is the consensus that Mitsubishi are more reliable?

[lopburi3]

If you are pumping from canal it probably should be a sump pump rated for sewage rather than a normal water pump.