Building a new house in Isaan

[sometimewoodworker]

4 hours ago, Muhendis said:

On reflection. Have a look at the pump control box. They usually have an input specifically for a tank float switch in which case a relay will not be necessary.

The relay isn’t necessary just because the wiring between it and the pump control box. FWIW none of our pumps have any wiring dedicated to a float switch.

 

If the power to the pump is switched by the float switch (this is how our setup works) then 200 metres is either going to require some significantly large cross section cable or a contactor near the pump so that the power isn’t having to from the PV -> 200m float switch -> 200m Pump 

 

So it is certainly possible that the pump control box contains a contactor as you suggest but one IS required due to the 400 metres of cable required from the tanks to the pump (200 x 2) either in the control box if it has one or external if it doesn’t.

Edited April 9, 2023 by sometimewoodworker

[Muhendis]

30 minutes ago, sometimewoodworker said:

So it is certainly possible that the pump control box contains a contactor as you suggest but one IS required due to the 400 metres of cable required from the tanks to the pump (200 x 2) either in the control box if it has one or external if it doesn’t.

I didn't actually suggest that the pump control box contains a contactor. 

My thinking is that the control box probably has a means of electronically disabling the power to the pump using volt free contacts.

Granted 400 Meters of copper could be pushing it a bit but if there is negligible current flow then it should not be a problem.

eg 1.5mm² cable is about 12.1mΩ/Metre so at 100mA the voltage drop would be about 0.5V so if the control box system voltage is 24V, the switching voltage would be 0V - 23.5V which is fine for most systems.

Best hold fire on that until we have seen the specs. though.

[sometimewoodworker]

12 hours ago, sometimewoodworker said:

FWIW 7 days will be enough to start filling and you will be able to troubleshoot the pipe work. However on the pipe work you are currently unable to isolate any one tank so any problem or need to clean a single tank will require you to empty all the tanks. We have only 3 but I can have each one isolated if I need to. Adding valves before you start filling is simple, after they are full, not so much.

This is our storage, 

 

here are the tank connections 

 

and should we ever need to drain the tanks we have stopcocks so we can either direct the flow or not have 2,500L flood out at full pressure.

[sometimewoodworker]

21 minutes ago, Muhendis said:

I didn't actually suggest that the pump control box contains a contactor. 

My thinking is that the control box probably has a means of electronically disabling the power to the pump using volt free contacts.

I don’t understand exactly what you mean by “electronically disabling the power to the pump using volt free contacts”.

I don’t know a way that the float switch (it switches up to 7.5A AC so not rated for DC switching ) can function in the way you suggest. 
if there is a way I would be interested to understand exactly how as I can’t think how it can work.

 

 

 

21 minutes ago, Muhendis said:

Granted 400 Meters of copper could be pushing it a bit but if there is negligible current flow then it should not be a problem.

That was the reasoning behind having a contactor at or near the pump/PV 

 

21 minutes ago, Muhendis said:

eg 1.5mm² cable is about 12.1mΩ/Metre so at 100mA the voltage drop would be about 0.5V so if the control box system voltage is 24V, the switching voltage would be 0V - 23.5V which is fine for most systems.

If there is a contactor in the suggested position then the trigger current would not be significant however using a 220V relay to switch the PV (12V~24V DC) current to the pump would probably be the best solution.

 

21 minutes ago, Muhendis said:

Best hold fire on that until we have seen the specs. though.

I agree.

[Muhendis]

36 minutes ago, sometimewoodworker said:

if there is a way I would be interested to understand exactly how as I can’t think how it can work.

Inside the control box there will be a drive circuit for the pump and a solar-to-system DC converter of some sort. There will probably be a processor to control the power going to the pump.

Inputs to the controller should include a tank water level switch probably isolated by a low power signal relay. If the isolation is by a relay then we are talking in the low voltage (24V) milliamp range which a water level float switch is easily good for.

The relay contacts, on closing due to water level high, would send a signal into the processor to tell it to stop powering the pump. After water has been used from the tank, the float switch would operate due to low level detected and the signal relay contacts would change over telling the control processor to power up the pump and send more water to the tank.

 

[Encid]

13 hours ago, sometimewoodworker said:

I didn’t elaborate on the wiring as it is really simple, however it seems that what is simple to me may not be as obvious as I assume. The 300 baht float switch has contacts that are capable of switching 16A (they are able to be wired usually on or usually off). However as the pump is 200 metres away an under 1A 220V AC (you can probably use low voltage DC if required) control current will make things easier, so you put your contactor near the pump so you don’t have a high current load for any significant distance. I am assuming that the power feed from the PV is close to the pump.

You are correct... I am not electrically minded at all with only basic knowledge of that field of engineering, so any suggestions would be highly appreciated.

 

I don't have a photograph of the control box but I have asked my niece to take a photo of it later today.

 

I do have a photo from when it was installed exactly 1 year ago... the control box is mounted directly under the PV panels which are directly over the bore/pump.

2 cables were originally connected to it and run alongside the pipeline before it was buried... the cables went to a switch at the power pole at the pond but it never worked... the guy who installed it said that the distance was too far.

I will look for them when I re-visit the farm again after Songkran.

 

[Encid]

5 hours ago, Muhendis said:

Do you have the control box spec?

If you do, post it on here so we can see where to make the connections.

I don't have a specification for the box... no documentation at all.

I have asked my niece to take a photo of the internals and send it to me this afternoon.

[Encid]

1 hour ago, sometimewoodworker said:

here are the tank connections 

 

May I ask why you used brass gate valves and not PVC ball valves?

[sometimewoodworker]

3 hours ago, Encid said:

May I ask why you used brass gate valves and not PVC ball valves?

The PVC ball valves degrade with UV exposure they can and do (yes I have had experience if this) become so degraded that they are worthless. I don’t remember the difference in cost but as I use the lazy man’s approach, which is only do something once and get it right, the difference is not that much factoring in my time.

[Encid]

Just now, sometimewoodworker said:

The PVC ball valves degrade with UV exposure they can and do (yes I have had experience if this) become so degraded that they are worthless. I don’t remember the difference in cost but as I use the lazy man’s approach, which is only do something once and get it right, the difference is not that much factoring in my time.

Sounds logical to me. 

 

My own experience with PVC ball valves is limited to those in our pool pumphouse... they get operated 2-3 times a week but they never see the sun so no direct UV exposure.

I have not had a problem with any of them in the 15 years that we've had the pool.

[Muhendis]

45 minutes ago, sometimewoodworker said:

The PVC ball valves degrade with UV exposure

Not only UV either.

One of mine was indoors and the wretched thing did it all on it's own.

[Muhendis]

4 hours ago, Encid said:

I don't have a specification for the box... no documentation at all.

That is worrying. It sounds like it may be a one off put together by a local "company".

[Encid]

Well it looks like I will have to wait another day before I can get a photo of the control box... my niece decided that she'd rather go to the market in Phon with her friends this afternoon instead of going to the hot and dusty farm. 

 

She is home for the holidays from her (uncle funded) University studies.

[Muhendis]

3 hours ago, Encid said:

Well it looks like I will have to wait another day before I can get a photo of the control box... my niece decided that she'd rather go to the market in Phon with her friends this afternoon instead of going to the hot and dusty farm. 

 

She is home for the holidays from her (uncle funded) University studies.

Sounds like the woman's got more than half a brain.

[Muhendis]

19 hours ago, Muhendis said:

Not only UV either.

One of mine was indoors and the wretched thing did it all on it's own.

I am now in the habit of fitting unions up stream and downstream of anything that might need to be changed/repaired in the future.

[Encid]

Well my niece came through with photos of the PV solar panel powered submersible pump control box... powering a 750W pump.

 

Here it is in the off position:

 

 

And here it is in the on position (with lights flashing apparently):

 

[Encid]

A bit of research led me to this website and Google Translate gives me the following:

 

ADVANTAGES OF DC DD SOLAR PUMP SUBMERSIBLE PUMPS
 
  1. Permanent magnet brushless synchronous motor: efficiency is improved by 15%-20%, saving energy. Reduce the use of solar panels
  2. 304S/S pump shaft
  3. Brassoutlet/Connector/Oil tank.
  4. Japanese NSK bearings, service life is 3 to 5 times longer.
  5. Model motor base Doublebearing Able to work under greater axial loads
  6. Alloy seals: Longer service life and high reliability.
  7. Motorcoil is made by automatic winding machine, with centralized winding technology, motor efficiency is greatly improved.
  8. Intelligent water shortage protection: The pump will automatically stop working when there is no water in the well and automatically start 30 minutes later.
      
  Controller: has the following properties
 
(1) Waterproof grade: IP65
(2) VOC range:
 
        48V regulator ： 50V-110 V;
        72V regulator ： 50V-150 V;
        96V controller ： 90V-210 V;
        110V controller ： 90V-210 V
 
  (3) Ambient temperature: -15 ℃ ~ 60 ℃
  (4) Maximum input current: 15A
  (5) MPPT function, higher solar utilization rate.
 
  (u6) LED shows the working condition of power, voltage, current, speed, etc.
  (7) Frequency conversion function: it can automatically operate with frequency conversion based on solar energy, and the user can also change
         Manual pump speed
  (8) start and stop automatically
  (9) Waterproof and anti-leakage: double seal effect.
  (10) Soft start: No excitation current protects the pump motor.
  (11) High Voltage/Low Voltage/Over Current/High Temperature Protection
  (12) Product warranty 2 years

 

Can any of you electrically-minded gurus use this information to tell me how I can automate the start/stop of the pump from our storage tanks 200m away?

[Muhendis]

Looking at the web site, this is the interesting part

https://www.daddee.co.th/17073644/ไดอะแกรมปั๊มซับเมอร์สdcbl-แบบคอนโทรลแยก

It clearly indicates the float switch connections.

The fact that your installer tried it and decided that the wires from the tank sensor to the control box were too long indicates quite a bit of current is needed to do the controlling bit.

I would fit a power relay in the control box and use it's N.O. contacts to connect to the control box. The current to drive the relay would come from a small power supply also added into the control box. the circuit would then be from the relay coil down a 1.5mm² cable to the tank sensor and back to the small local power supply.

Power from the solar panel could be used for the local power supply (solar panel Voc needed). If the solar panel output is not suitable then a small dedicated solar panel can be added. 

Some design and verification work is required but it is not complicated.

 

[Encid]

I do have PEA supplied 220V AC power available at the storage tanks area... it powers the Mitsu water pump.

Could that power be utilized to provide the necessary current to power the relay?

[Encid]

Some more work in progress while we wait for the roof steel to be delivered... the 2" PVC ring main around the pond was laid in a trench, and was also run across to the retaining wall where it will supply the guest house water tank.

 

Power supply cables were also run inside a 2" PVC pipe in the same trench, then the trench was backfilled.

 

We will clearly mark the route of the underground piping so that we don't accidentally dig it up or break it in the future.

 

 

 

 

 

 

 

[Muhendis]

33 minutes ago, Encid said:

I do have PEA supplied 220V AC power available at the storage tanks area... it powers the Mitsu water pump.

Could that power be utilized to provide the necessary current to power the relay?

Yes, that saves a lot of bother. The cable has to be higher rated than the low voltages I had in mind.

2core NYY 1.5mm² would do.

It's worth trying to connect your float switch direct to the control box sensor input via your 200metre cable before fiddling around with a relay and 220v mains power.

If it works. you don't need the relay and if it doesn't work, you do.

Either way you will need that cable.

[Muhendis]

Now I know what I want for my birthday 

 

[Encid]

Some of the roof steel has been delivered, but not all...

 

 

So the workers have started on the erection of the AAC block walls.

The building will have a double cavity wall on the west side only, all other walls will be single 75cm blocks.

The south side will be fully shaded by the  roof over the outside decking and the Thai kitchen, which in turn will be shaded by the carport.

 

 

 

 

 

 

 

[Encid]

Some of the building team are staying on and not going home for Songkran, so our build is continuing (despite the heat), albeit at a slower pace.

 

It is good to see that they are following the recommendations provided in the QCON Handbook for fixing the AAC blocks to the RC columns.

 

 

 

 

 

 

 

 

It is also good to see that they are using a laser level as well as the string lines for their work...

 

 

[Dante99]

1 hour ago, Encid said:

It is good to see that they are following the recommendations provided in the QCON Handbook for fixing the AAC blocks to the RC columns.

Look again.  The drawing shows the rebar from the post going into the center of the block.  The photos show the worker putting it into the edge of the block. Maybe an insignificant difference but .....

[Muhendis]

11 hours ago, Dante99 said:

Look again.  The drawing shows the rebar from the post going into the center of the block.  The photos show the worker putting it into the edge of the block. Maybe an insignificant difference but .....

The method show in the Qcon drawing is indeed different to the way the worker is doing it. However, I've had a look at the Qcon manual and the method the guy it using is mentioned with pictures.

 

I am particularly interested in this as I will soon be building a new temperature maintained solarbattery, charger and inverter room.

 

Looking at the detail of what is required in the manual is putting me off using AAC blocks a bit ????.

[Encid]

18 hours ago, Dante99 said:

Look again.  The drawing shows the rebar from the post going into the center of the block.  The photos show the worker putting it into the edge of the block. Maybe an insignificant difference but .....

The method that the worker is using in the photo is also recommended in the QCON Handbook... 

 

[Encid]

7 hours ago, Muhendis said:

Looking at the detail of what is required in the manual is putting me off using AAC blocks a bit ????.

I think that all the levelling that is mentioned in the manual is going a bit overboard, particularly if the walls are going to be rendered then painted afterwards (which ours will be).

 

Our builder is using a single thin bed mortar layer of about 3-5mm only, and I'm happy with that as ours are not load-bearing walls.

[Encid]

Despite a small work crew and mid-to-high forties daily temperatures, the walls are continuing to rise up.

 

My niece takes her mother and all the family dogs out to the farm in the late afternoon to take photos for me... it's still pretty warm but not as brutal.

The dogs seem to enjoy the freedom and exercise despite the heat and the dust.

 

Everyone is praying for rain... maybe this weekend?

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[Encid]

Work stopped for a few days as the crew decided to go home to celebrate Songkran with their families and friends, but were back on the job again today.

 

The walls are continuing to rise and the openings for the windows have been located.

RC lintels have been positioned both above and below the window openings.