Leaking pump, time to renew?

[clivebaxter]

No idea how long these Mitsu pumps are meant to last but this one is 9 years old. Leaking from somewhere, slightly. Not the pipes or from the black nut at the bottom so must be right underneath. Is this a common fault when they have been in a while? Also, are those smaller box like ones any better, mainly for shower upstairs?

Edited January 19, 2022 by clivebaxter

[NanLaew]

Our first one lasted about 14 years before a pinhole appeared in the pressure tank. Replaced it with same brand/type but the next biggest HP in the range as the house and outlets had also expanded during those 14 years.

 

I bought a replacement tank on lazada and got a set of new o-rings and seals from the local water pump emporium and rebuilt the old one. This pump is now a spare but has been used a couple of times to feed water to yai's allotment and the brother-in-law borrowed it when his own pump went tits up.

[lopburi3]

A pin hole would not be uncommon as they do rust - new tanks are available but if you want more pressure probably better to buy pump that can provide.  Believe the new box constant pressure pumps are generally higher pressure (although some are louder than a jet plane) but changed to Grundfos many years ago to overcome the shower issues (very good/quite and high pressure pumps).  But be aware any increase in pressure could cause issues for some plumbing here - we had to redo our house built on 1975 to new pipes (external now and really not that hard or expensive to do).

[sometimewoodworker]

1 hour ago, clivebaxter said:

No idea how long these Mitsu pumps are meant to last but this one is 9 years old. Leaking from somewhere, slightly. Not the pipes or from the black nut at the bottom so must be right underneath. Is this a common fault when they have been in a while? Also, are those smaller box like ones any better, mainly for shower upstairs?

What you have is from the Well Pump series, they fluctuate in output pressure.  They also tend eventually to develop a hole in the pressure tank which is easily replaced and also need to have the tank air cushion replaced by bleeding the water from the tank.
 

The square pumps are Constant Pressure versions and Mitsubishi recommends those for showers, and cost almost exactly the same for a similar powered pump.

[sometimewoodworker]

2 minutes ago, lopburi3 said:

A pin hole would not be uncommon as they do rust - new tanks are available but if you want more pressure probably better to buy pump that can provide.  Believe the new box constant pressure pumps are generally higher pressure (although some are louder than a jet plane) but changed to Grundfos many years ago to overcome the shower issues (very good/quite and high pressure pumps).  But be aware any increase in pressure could cause issues for some plumbing here - we had to redo our house built on 1975 to new pipes (external now and really not that hard or expensive to do).

For Mitsubishi pumps of similar power there is no difference in output pressure between the WP and EP series 

I also got a Grundfos pump so I can increase the house pressure if needed.

[lopburi3]

7 minutes ago, sometimewoodworker said:

For Mitsubishi pumps of similar power there is no difference in output pressure between the WP and EP series 

I also got a Grundfos pump so I can increase the house pressure if needed.

But there are a number of makes so not sure what pressures that all produce, suspect some are higher pressure and compete with Grundfos - we run our Grundfos 3.5 - 4 Bar and works well for good shower pressures.

[sometimewoodworker]

11 minutes ago, lopburi3 said:

But there are a number of makes so not sure what pressures that all produce, suspect some are higher pressure and compete with Grundfos - we run our Grundfos 3.5 - 4 Bar and works well for good shower pressures.

The other major brand, Hitachi, pressures are the same or slightly lower than Mitsubishi and none of them go above 3 Bar. So it looks as if Grundfos are alone of the major brands to exceed that.