romichen

All,

Thank you so much for all the replies and information. This is my thinking:

1. The water tank is on the ground level, same as the pump. Connection between these 2 is on the ground too, so I see no chance for air to go from tank to pump.

2. AND, there was NO valve between pump and tank! When the workers came to change the pump, they had to empty the whole tank first... what a waste......

3. I never knew on WP-155 the tank supposed to be dry. And of course I never knew I can try to release water from it! I did it only once ( driven by curiosity), and quite a lot of water came out from there. So again I am confused how this WP type works....

At the end, the workers add one valve between the water tank and the pump, changed the pump to EP ( I think this one doesnt have that pressure tank). And so far everything is running smoothly!

Hey everyone, this is my first post here, I would like to discuss abt water pump since that's how I found this useful forum.

I rent and moved into a new-built house in Dec 2009. Water pump in the house, is Mitsubishi WP-155Q3. After around 2-3 months, I start to experience problem with it.

When I came back from work around 7-8 PM, I start to find no water from the taps. At first I thought it's the public supply got problem, but soon I realized it was only my house since neighbors are watering the lawn. So I complained to the landlord, then the person in charge of the village came, checked, and told me I just need to release the air trapped in the pump, which is caused by bubbles in the water supply. Since this was the first time I take care of a stand-alone house (before I always stayed in apartments, or compounds), I had no experience at all. So i followed his instructions, whenever there is no water, I go to check if air trapped there, and release them.

At first it worked well, every time I did see air there, and pressurized, and the pump was hot. So I released the air, and restarted the pump. However, 2 months later, things started to get worth, I have to release the air every 2 days. And sometimes there was no air at all, but pump was overheated (even in the midnight, so, not due to sunshine). I start to doubt something wrong with the pump. I complained again, same person came, checked, told me nothing wrong. FINE. I repeated to switch off the pump and on every 2-3 days. Until...

One morning, I woke up, and there is no water. I went out, found the orange cap was lying on the floor, the black cap for the check valve ( the one with spring) is gone, the spring and the check valve are gone too. Water is coming out from that spot and I can hear water flowing from public source to water tank. I found some parts and replace the missing ones, put all back to place, and went to work. When I came back from work, I found exactly the same scene. So I complained to the landlord again. And wait for the village guy to come and fix.

While waiting, I searched online, and found an very useful article here posted last year. With the information, I figured out the configuration I have here:

- I have one water tank sitting on the floor, water from public system fill this tank, and a floater controls the level of water ( roughly 1.5m higher than the pump).

- Another pipe goes from public system directly to the house, meet the supply from water pump before entering the house. Thus there is a bypass valve on this line.

- In case pump fails or no electricity, water pump will be shut and bypass line open, to give low pressure water to the house.

So.... the guy from village came when I was in office, he called in and claimed that nothing wrong. I was suspicious, but I couldn't do much until I came back home from work and check myself. When I arrived, I found the bypass valve was open, and pump was running non-stop ( it's pumping in a loop). Fine, I knew the guy was messing around now, so I shut the bypass, went inside, and took a shower. When I took shower, the nut to hold the heater's water pipe broke at the moment I started the water. Strange....I thought. 1 hour later, I heard a drum-like sound, I went out, the check valve burst out again. &^%#$%$^%&

Everything seemed to start break down. So I decided to start my own troubleshooting (at 11PM). By playing with the valves, I found out that possibly the pressure switch doesnt work this time. So I opened the switch box, expected to see ants, or any other insects inside, BUT, no... it's shining clean. Okay, I have to wait again!

This morning, landlord sent her own troops, instead of the village guy. They did some check, got same conclusion as I did, and changed the whole pump! Now I'm using EP-155Q3, the square one. According to them, it's better than WP-155Q3.

It seems like the problem is solved. However I am not sure how long it will take before another problem shows up. And, I am still confused with below things:

- I checked the water tank myself, it was clean and full. So how can bubbles/air go inside the 1st pump?

- can overheat of a pump damage the pressure switch? Because I heard people saying pressure switch seldom fails..

- Anyone has a specification for EP-155Q3? What's the difference between this one and WP-155Q3? Seems like WP has a kind of small tank at the bottom...

Thanks... Qing