WP pressure tank

[Susco]

Yesterday I plugged the second hole on my Mitsubishi pump pressure tank, so time to replace I guess.

 

I see them on Lazada, in the original yellow version, and in the stainless steel version, which is a little cheaper.

 

Anyone experience with this, which of both I should select?  Since the pump is now almost 10 years old, does it make sense to replace the tank, or should I instead save money by replacing the complete pump?

 

Is Lazada the place to look for the tank/pump, or will there be cheaper places.

 

I'm in Pattaya

[VocalNeal]

Tanks are cheap? About 1800 baht? Easy job. SS ones are a bit more in my experience. A local plumbing/pump shop will have both. 

[bankruatsteve]

10 years is getting up there for a Mitsu.  Check for corrosion on bolts and joints. Decide yourself if new pump or just tank is needed. Be careful with Lazada as the model number is often not the same as pumps sold locally. 

[steve73]

I've used a 2m length of 2" PVC pipe to provide some "surge volume" to supplement/replace a failed pressure tank.  Include a vent and drain, since the air will slowly deplete over a few months as there's no bladder.  I have thought about inflating a bicycle inner tube to overcome this, but the need to drain every few months has never really made it necessary.    

[Susco]

1 hour ago, bankruatsteve said:

10 years is getting up there for a Mitsu.  Check for corrosion on bolts and joints. Decide yourself if new pump or just tank is needed. Be careful with Lazada as the model number is often not the same as pumps sold locally. 

 

OK, since I actually have 2 pumps of the same age, each feeding one side of the house, and I see the smaller one is leaking from one of the bolts, maybe better to replace the complete pump.

 

2 pressure thanks would cost me 5000 Baht, and if then the pumps fail in the near future, that is 5000 wasted.

 

One is the Mitsubishi WP405 and the other WP305.

 

Now I'm considering to replace both pumps with a single one, that feeds both sides of the house. Would that be possible?

 

I have 2 separate suction pipes of 1". I know the WP405 requires 1 1/4", but that's the builders' error. The output pipe is 1 1/4"

 

Can I have 1 pump feed from 2 separate suction pipes?

 

Any suggestions which pump would be up to the task, and doesn't break the bank?

[bankruatsteve]

1 hour ago, Susco said:

Can I have 1 pump feed from 2 separate suction pipes?

 

Any suggestions which pump would be up to the task, and doesn't break the bank?

 

Do you commonly have multiple taps open at the same time?  I would think either one of those pumps could easily handle a whole house with "normal" usage.  Most of us will have 150 to 250 W pumps for adequate flow.  Grundfos is the pump if you need macho flow.  Otherwise, I have been happy with my Hitachi and I know Mitsu has loyal users too.  The main concern is when parts or repair might be needed and if that is locally available for whatever brand you might choose.

 

I don't know of any reason you should not join the tanks to a single input.  if you just want a single pump, you might as well as long as they are there.  Pipe size isn't critical for most domestic use but you would want to keep it at the max size as far as possible.

[Susco]

1 minute ago, bankruatsteve said:

Do you commonly have multiple taps open at the same time? 

 

I don't, as i'm single haha, but the house has 3 bathrooms, kitchen, maids quarters with bathroom and full kitchen, and the setup was done with it all being occupied in mind.

 

Because it isn't now, doesn't mean it may not in the future.

 

Need to think about.

 

If I decide to just replace the pressure tank, which would be the best choice qua durability, the yellow Mitsubishi tank or the stainless ones?

[bankruatsteve]

3 minutes ago, Susco said:

 

I don't, as i'm single haha, but the house has 3 bathrooms, kitchen, maids quarters with bathroom and full kitchen, and the setup was done with it all being occupied in mind.

 

Because it isn't now, doesn't mean it may not in the future.

 

Need to think about.

 

If I decide to just replace the pressure tank, which would be the best choice qua durability, the yellow Mitsubishi tank or the stainless ones?

Unless you need firehose pressure, I'm pretty sure a 250-300 W pump could handle that.

Don't know about Mitsu tanks but I would be inclined to go with a Mitsu replacement versus unbranded.

[lopburi3]

17 minutes ago, bankruatsteve said:

Grundfos is the pump if you need macho flow

Not only flow but PSI of 50/3.5 bar (normal US water pressure).  You will not get that from the well pumps.  But on the other side the well pumps will likely not blow your plumbing.  In our case we went Grundfos many years ago and re-did the plumbing to take the higher pressure and very happy with results.  

[Susco]

16 minutes ago, lopburi3 said:

Not only flow but PSI of 50/3.5 bar (normal US water pressure).  You will not get that from the well pumps.  But on the other side the well pumps will likely not blow your plumbing.  In our case we went Grundfos many years ago and re-did the plumbing to take the higher pressure and very happy with results.  

 

The pumps are automatic pumps, not well pumps.

 

Strange enough I can't find anywhere any specs as to what pressure the Mitsubishi WP 405 delivers.

 

Any info on that one?

 

Edit : Found it 2.4 - 2.8 bar

Edited June 20, 2021 by Susco

[bankruatsteve]

The pressure is a factor to flow rate but the best way to decide if you are getting what you want out of a pump is to measure the flow rate.  (container of known size, hold under full open tap until full, measure time it takes  to do that).  Different taps may have different flow rates.

 

Most people are happy with a flow rate of 25 l/min give or take.

 

Edit:  Actually 25 l/min is good for my lawn sprinkler.  I'm good with 5 l/min for most other things.

 

Edit 2:  Just to continue the thought...  Measure again with 2 taps open, 3 taps open.  That could be 1/2 and 1/3 compared to 1 tap open (and that might be good enough) but depending on the pump size and a bunch of other factors multiple taps open might be pretty much the same as just 1 open.

Edited June 20, 2021 by bankruatsteve

[Yellowtail]

I would think one pump would be fine. How is the system configured? Do you have one tank or more?

 

The only difficulty converting to one pump will be tying the two systems together. 

 

I have three-bedroom, three-bath & three people and  the Mitsu  EP-355 R handles it without an issue.

[lopburi3]

1 hour ago, Susco said:

 

The pumps are automatic pumps, not well pumps.

 

Strange enough I can't find anywhere any specs as to what pressure the Mitsubishi WP 405 delivers.

 

Any info on that one?

 

Edit : Found it 2.4 - 2.8 bar

I had several WP405's before change to Grundfos and believe they are made for shallow wells and were advertised as such.   Yes they are automatic.  They are about the strongest pressure and largest for normal home use.

[Susco]

2 hours ago, Yellowtail said:

I would think one pump would be fine. How is the system configured? Do you have one tank or more?

 

The only difficulty converting to one pump will be tying the two systems together. 

 

I have three-bedroom, three-bath & three people and  the Mitsu  EP-355 R handles it without an issue.

 

I have an in-ground tank, but there are 2 suction pipes of 1" inserted, and they arrive next to each other in the pumphouse, because both pumps are positioned next to each other.

 

Then each pump feeds one zone, so I think tying them together will be easy.

[Yellowtail]

Just now, Susco said:

 

I have an in-ground tank, but there are 2 suction pipes of 1" inserted, and they arrive next to each other in the pumphouse, because both pumps are positioned next to each other.

 

Then each pump feeds one zone, so I think tying them together will be easy.

 

That's what I'd do. You have the 1 1/4" in on the pump you can T the two 1" suction tubes together to, and you can split the 1 1/4" out on the pump to the two 1" feeds to the house. 

[sometimewoodworker]

17 hours ago, Susco said:

Strange enough I can't find anywhere any specs as to what pressure the Mitsubishi WP 405 delivers.

 

Any info on that one?

[sometimewoodworker]

18 hours ago, lopburi3 said:

In our case we went Grundfos many years ago and re-did the plumbing to take the higher pressure and very happy with results.  

The current SCALA 2 inverter can be set up to 80psi

 

“The pressure indicator shows the required outlet pressure from 1.5 to 5.5 bars (22 to 80 psi) in 0.5 bar (7.5 psi) intervals.”

[lopburi3]

32 minutes ago, sometimewoodworker said:

The current SCALA 2 inverter can be set up to 80psi

 

“The pressure indicator shows the required outlet pressure from 1.5 to 5.5 bars (22 to 80 psi) in 0.5 bar (7.5 psi) intervals.”

We run between 3.5 and 4 bar (50-60 psi) on older model with pressure tank and find that keeps good shower pressure (main reason for wanting higher pressure).  Have an 8 person household.