Mitsubishi water pumps?

[Orton Rd]

can somebody say what the difference is between the box like EP pumps and the taller round WP ones? Have to get a new one as ours has always been under powered WP type. At 150 rating it's not powerful enough to get enough pressure upstairs, would 250 be enough? only one bathroom

[wayned]

EP are constant pressure pumps, WP are not.  The WP has a large accumulator tank and has a cut on and cut off pressure so the actual pressure lowers until the motor cuts on and then rises to the maximum pressure that causes the motor to turn off.  I have WP255"s in both houses and have had for 19 years,  and really don't recognize any drop in pressure while showering.  There's a good Mitsibushi table that has the specs for their pumps in a recent post on another thread.  I'll take a look and direct you there if I can find it.

[wayned]

Table in post #2 of this thread:

 

[VocalNeal]

If you look at the table below you will see that the switching pressure from a 250W pump is the same as the 150W the difference being the volume of water delivered not the pressure. You will also see that the volume for the EP pumps per wattage is the same as WP. 

The difference is that the EP pumps have a flow switch which overrides the pressure switch to allow the pump to generate a bit more pressure while the water is flowing. When the flow stops the pressure switch cuts off the pump. 

 

But you can also see that if you went up from a WP 150W to a 200 or 250W you would get an extra 1 bar pressure difference in switch operation and an additional lift height of 4 to 7m. 

 

If you stick to a WP you probably won't have to change and "blue" piping. (proven wrong)

Whereas fitting an EP would require a piping rework.

When in the store check a WP-155 against a WP-205 or 255 to check they are the same which I think you will find they are. So you simply unbolt two fittings and.....

 

I have a WP-205 and one bathroom on the third floor.

 

Please unplug the pump before doing anything. 

 

 

As has been pointed out to me there are some more powerful Mitsubishi pumps for mansions or small condo buildings. But again these would require piping rework and stout plumbing as they almost double the head.

 

https://www.meath-co.com/web/product_list1.asp?series_no=78

 

Edited October 3, 2017 by VocalNeal

[wayned]

12 minutes ago, VocalNeal said:

If you stick to a WP you probably won't have to change and "blue" piping

Unfortunately that is not true.  I went from a 155 to 255 and had to re-plumb as the ports are not at the same heights and distance apart.

[VocalNeal]

^ OK. It was a long shot as i have only worked on a 205.

[wayned]

I rebuilt the 155 and it's sitting in the shop as a spare, but would have to change the pipes to fit it>

[Pib]

The WP80 thru 155 series only put out 1.3 to 1.9 bar...or let's say an average 1.6 bar/23 psi.  This is not much pressure when needing to reach up to a 2nd or higher story the pressure will be even less.  And the WP80 thru 155 series water "volume output capability" is on the low side. Such pump pressure/volume is OK for single story homes and if you don't desire much pressure. 

 

The WP 205 thru 405 series put of 2.1/2.4 to 2.8 bar...or let's say an average 2.4 1 bar/35 psi.   That is quite a bit more pressure than the WP80-155 series.  And the water volume is capability is much higher than the WP80-155 series.

 

I have had a WP-255 for 9 years now to provide water to my two story home....works fine for pressure and volume of water needed...you really don't notice any pressure variation at the water taps, shower head, etc.   

 

A WP design is definitely more popular than an EP series based on the water pump designs I see installed around my Bangkok moobaan and my in-laws villages out in the provinces.  WP series are cheaper than the EP series and generally cost less to repair since the WP series doesn't have the extra electro-mechanical constant pressure valve....nor the small pressure bottle which must be completely replaced when it fails since it has an internal rubber diaphragm.. .the WP series has the much larger pressure tank which does not use a rubber diaphragm.

 

A person probably should go with approx a 250 watt pump (WP or EP series) for a two story home (or one story home) when wanting significantly more pressure and volume capability....the 250 watt point seems to be the point where most pumps take a very significant increase in pressure/volume capability.   

 

 

 

[sometimewoodworker]

6 minutes ago, Pib said:

The WP80 thru 155 series only put out 1.3 to 1.9 bar...or let's say an average 1.6 bar/23 psi.  This is not much pressure when needing to reach up to a 2nd or higher story the pressure will be even less.  And the WP80 thru 155 series water "volume output capability" is on the low side. Such pump pressure/volume is OK for single story homes and if you don't desire much pressure. 

 

The WP 205 thru 405 series put of 2.1/2.4 to 2.8 bar...or let's say an average 2.4 1 bar/35 psi.   That is quite a bit more pressure than the WP80-155 series.  And the water volume is capability is much higher than the WP80-155 series.

 

I have had a WP-255 for 9 years now to provide water to my two story home....works fine for pressure and volume of water needed...you really don't notice any pressure variation at the water taps, shower head, etc.   

 

A WP design is definitely more popular than an EP series based on the water pump designs I see installed around my Bangkok moobaan and my in-laws villages out in the provinces.  WP series are cheaper than the EP series and generally cost less to repair since the WP series doesn't have the extra electro-mechanical constant pressure valve....nor the small pressure bottle which must be completely replaced when it fails since it has an internal rubber diaphragm.. .the WP series has the much larger pressure tank which does not use a rubber diaphragm.

 

A person probably should go with approx a 250 watt pump (WP or EP series) for a two story home (or one story home) when wanting significantly more pressure and volume capability....the 250 watt point seems to be the point where most pumps take a very significant increase in pressure/volume capability.   

 

You have missed the new multi stage pumps, the UMCH series that have a pressure tank, the CMCH that are constant pressure versions and the inverter IP-505, these are all quieter than the older single stage ones

[kamalabob2]

The Mitsubishi Multistage Pumps are sold at water pump dealers and not at  Home Furnishing stores. The Inverter pumps of both Mitsubishi and Hitachi are sold at most any big box retailer with water pumps. There is a huge difference in price between a Mitsubishi Super Pump UMCH series and an inverter water pump in Thailand.  The Mitsubishi ICM - C Torrent 2 Inverter series water pump is used in hospitality or industry and not often in a typical size home in Thailand. 

[Pib]

4 hours ago, sometimewoodworker said:

 

You have missed the new multi stage pumps, the UMCH series that have a pressure tank, the CMCH that are constant pressure versions and the inverter IP-505, these are all quieter than the older single stage ones

 

Yea, no storage of various type of pumps to choose from.  I only meant to talk the WP and EP series which are the most commonly bought.  Various series of pumps among manufacturers....low cost...high cost...inverters....multistage...etc.   

 

For me the inverter type pumps are a little too pricey to buy and probably to repair with their extra electronics....pretty much like how inverter A/Cs are significantly more costly to buy and repair than regular/fixed speed A/Cs.  But they are slowly getting cheaper as more people buy them.  

 

While inverters can save a person electricity money when the inverter needs to run a lot during the 24 hour period like on an A/C or refrigerator....however, for a home water pump that probably spends over 95% of the 24 hour day not running a person will probably never recover through electricity savings the higher price for an inverter home pump regardless of pump advertising.

 

And the multi-stage pumps are probably overkill for the typical home also.   But I would lean towards buying a multistage pump (if it was quiet) over an inverter pump.   I've only had one exposure to one Mitsubishi IMC-C multistage pump in actual operation....the Super Pump just like in the picture above.  A person in my moobaan has one...has it close to his fence bordering the soi which I walk by occasionally.  He use to have it sucking directly from the soi main but he later added a storage tank the pump sucks from now.  I would say it's a little nosier than a WP/EP series pump but the guy does not have it setting on a concrete pad...just a couple of flat rocks instead....proper mounting would probably make it more quiet.

 

By hey, my WP255  pump is almost 10 years old....over those almost 10 years I had to replace the pressure switch and the air control/balance valve....this parts cost come to around Bt1500 for actual Mitsubishi replacement parts...would have been cheaper (less than a Bt1000) with generic parts...I replaced them myself since the WP series are pretty simple machines to maintain since there are no extra electronics involved like flow control valves, inverter boards, etc.  

 

Now back in late 2011  I bought and installed a Mitsubitshi WP85 for the MIL's little one story house in the provinces.   It sucks directly from the soi main like everyone else in her village.   So far i's developed  a small leak/hole on the underside of the pressure tank (hard water in her area) that I had brazed/fixed for Bt100...no other repairs required.

 

I like the simplicity of the WP series...something I can easily troubleshoot/fix cheaply. 

 

 

 

[Orton Rd]

Why would you need the constant pressure ones in a house anyway? Think I will go with the wp 250 watt one as a replacement for the 5 year old 150. 

 

 

[sometimewoodworker]

34 minutes ago, Orton Rd said:

Why would you need the constant pressure ones in a house anyway? Think I will go with the wp 250 watt one as a replacement for the 5 year old 150. 

 

 

If you have an electric instant hot water shower then you should have a constant pressure pump, to maintain a constant temperature from the shower. This is a Mitsubishi recommendation.

 

The WP series will usually need the tank draining occasionally.

the prices for similar power Mitsubishi EP (constant pressure) and WP are usually very close to each other 

[Orton Rd]

We have electric shower but never noticed a problem with the wp, just not quite enough water

[Pib]

I have 6000W heaters in my two upstairs bathrooms....as mentioned earlier I have a WP255 and have plenty of pressure/volume coming from the showers...can not notice any pressure variation.

 

Now a couple years back when the air balance/control valve which maintains the proper air & water mix in the pressure tank went bad the failed valve caused the pressure  tank to become waterlogged--and then you did notice BIG variations in pressure...pulsating pressure.  The water flow coming out of the shower heads would "pulsate" due to the pump turning off and on at rapid rate since the pressure tank was waterlogged.  Replaced that valve which fixed the waterlogging problem....back to steady pressure again.