My tank feeds a pump so that it has enough pressure to supply the home. And it has two isolator valves, one for the municipal supply and one on the output side of the pump. (OK it has more, but these are the relevant ones here).
The usual situation is that one of those valves is closed and one is open, so that the house uses one supply or the other.
Question: If I have them both open, can the water from the municipal side push back against the pump and cause damage?
The pump is a JoJo with a control panel on it. Variable speed. One can hear the pitch of the whine changing.
Not a problem as I see it but better to use a changeover valve (one outlet and 2 inlets)
The only issue Iāve had is with single phase pumps is if you power up the pump when itās running in reverse (driven from the pump) it will then continue to run in reverse..
Will it go back to turning the correct direction after you stop and power it up again? I have a motor which blew a cap and after that it started turning in the wrong direction and I could not get it to swop over again at the time.
There are two ways a single phase motor can be made to go the right way.
On larger motors, you physically wind a second winding on at a 90Ā° angle, and use a capacitor to create out of phase current, to create the slip needed to drive the motor in that direction.
On smaller motors (desk fans, etc), an extra winding is wound around one of the poles, with a capacitor connected to create an out-of-phase current. This causes just enough slip to make the motor want to go in one direction.
Such a larger motor with an auxiliary/starting winding can only turn in the direction that its physical construction allows for. You can overpower it and cause it to run the other way, but after correcting any problems, it should always return to the original direction.
This is all head knowledge for me though. Practically? Not much experience.
I just checked the manual for the pump. It can pump in either direction, but the default setting is from the tank to the property.
Currently I have a timer that just turns the pump off at a certain time each evening. This is partly to be considerate to neighbours, partly because every now and then it decides to run at 2 or 3 in the morning when I think such noise is really a bit too much (I may be being a bit too sensitive, but Iād rather err on that side).
The problem with this arrangement is that we have no pressure from the pump from about 22:30 to 7:30. Most days there is enough supply available that we can make coffee early in the morning if we want. There is not enough to shower.
So now I have an idea to use an IOT device to simply open the valve that allows municipal supply straight through to the house. But with the valve for the pump supply left open, the municipal supply may push back against the pump.
I have had this situation (both valves open) before, but never for long. It seems to have not caused any problems. But if I leave it like that for hours? IDK.
Yep. I could get two of those IOT devices. But that means using one more 230V AC socket than I have available.
The 12 month warranty is expired now, so Iām not worried about voiding that (the conditions are many) but why punish that pump if I donāt have to?
Or I can call the plumber in and ask him to fit that change over valve. But wouldnāt he have done that if he could?
Hi Richard, Iām not sure which part of my post you are confirming.
The pump is just out of warranty, but I donāt want to inflict unecessary punishment upon it. The warranty conditions are quite strict. EG you may not use an āunapprovedā extension lead to take power to the pump. You also may not remove the three prong plug it arrives with.
TBF, Jojo do provide support whilst the pump is under warranty. They have a team of mobile support guys who are knowledgable and usually packing a couple of spare pumps in their vehicle.
Iām a bit confused about how this pump is used.. Are you using it to maintain pressure whilst supplying water from your tank to the house and is this your regular operation?
If so how do you keep the tank filled with water?
PS: I have found on another forum that the OP launches into a scenario which he expects you to fully grasp but he hasnāt explained it..
OKā¦ I have a backup water tank. The idea is that this is filled from the municipal supply. When the municipal supply goes down, then I switch over to the tank. This is where the pump comes in. It is on the output side of the tank, and provides enough pressure to feed water throughout the home.
Both the municipal supply and the output from the pump have isolating valves. The idea being that only one supplies the house at a time. The municipal supply actually has two isolators. One closes off the supply entirely, including to the tank. The second just stops municipal supply into the house. When I want to switch to the tank I should flip the isolators. Open the isolator between the pump and the house, close the isolator that allows municipal supply into the house.
But the water in the tank needs to be circulated and topped up, otherwise it will stagnate. The recommendation I was given by the plumber is to run the tank on weekends. That will cause enough circulation to keep the water inside the tank clean.
But I worry. The plumber who gave me this advice has more people in his household and a smaller tank. I went for 2.5 kl because that should keep our home going for a week, probably a bit more, if there is no municipal water. So I think I need to spend a bit more time turning over the contents of that tank.
So I tend to run off the tank during the day. My current MO is that the isolator for the municipal supply into the house stays closed, so we take water from the tank, and the tank gets topped up. I use a timer to stop the pump over night because Iām lazy and/or forgetful and donāt always flip the isolators and turn the pump off, and because the pump will sometimes run in the small hours.
So I am thinking of ways to have better control. One is to use an IOT device to control that isolator that allows municipal water into the home. Then we have pressure at night.
But I am inclining towards two IOT devices. I can turn the municipal supply on, turn the pump supply off, then kill the power to the motor. In the morning I need to turn the power on first, then toggle the isolators. This will keep me amused for a while, but itās not perfect. Just less imperfect.
although I donāt have your problem, I bought these valve from geewiz. I use them to route hot solar geyser water to either the house / washing machine / dishwasher / gas geyser (winter time)
ja nee plumbing can be risky. years ago they tried to steal my brass tap in the front garden. fortunately I had secured the tap with long wall plugs into the wall. but they damaged the pipe right at the bottom at ground level. I had to dig the tar away and install a stopper. needless to say I had to install it before sunset otherwise Iād have no house water. that led me to install jojo tanks so I can shut off mains and still run pressurised water to my house while I effect repairs at my leisure.
I battled a bit with the 5vdc power supply for these valves as I wanted them to run off my inverter setup and not off supplied USB charger. bought 2 x 220vac - 5vdc power supply from ACDC mounted one power supply in a barely suitable plastic box for the washing / dishwashing machines. the other 2 valves & power supply will be for the solar & gas geysers.
what I want is to prioritise the solar geyser temperature - this will then dictate where the summer time hot water goes to first eg. house and in winter it will re-route the solars luke warm water to gas geyser first to be boosted back to 65 degrees > then to house. this way Iāll always have hot water regardless of external influences.
same principle applies to the washing machine & dishwasher hot water - all depends on the solar geyser temp. just need to find a way to trigger the smart scene when I switch on the washing / dishwasher.
So in the end I got two tuya valve controllers. They canāt be controlled by the Astute app and vice versa, but Google Home can access them all via their respective apps, and also allows the creation of automations that tie them together.
So in the evening the city water gets turned on, then the pump outlet valve gets turned off, then the power goes down.
I just watched it change over.
In the morning the reverse sequence will happen.
Set & forget.
I know. In the cloud. It does mean I can take one small step towards world domination by controlling my water supply remotely.
The next problem to solve is power supply. The pump power is via a weatherproof box on the wall. This accommodates two 3 pin plugs, but thereās no room for adapters, so I canāt get the 12v supplies that the controller wants in there. So right now I have an extension lead running to under the pump controller and the power supplies are plugged in there.
I am aware of that trap. Though said awareness may not amount to actual avoidance. Already I am seeing complicated sequences of events that, in the end, wonāt do much that I actually need doing. I may get a smart controller for the guest geyser, and just set it to turn off at a certain time of day. Thereās not much need for that geyser, but it does sometimes amuse me for a while to turn it on on a sunny day and see how long it takes to get up to temperature.
Swimming pool? Maybe.
I have a regular timer on both devices already. And they are on the non-backed up side of the property and so they could lose power and then I have to be concerned with what state theyāre in when power is restored, and have multiple programs per day to make sure they get back to the state I want them to be in. This does not seem to be a problem with the conventional timers. Or is it? I canāt remember.
Depends on the type of timer. If you use the kind that has a rotating dial then you will have all sorts of problems if the power goes off at midday and comes back at 6 in the evening. Push button timers seem to have more flexibility and to be less thrown off by an outage. Presumably as long as the internal battery lasts.
Youāre right! Things can get complicated. āIf it aināt broke, donāt try to fix itā is a good principle.
What makes this type of control a challenge is that there is always more than one criteria to be addressed at any time. Because we tend to focus on the topic of the moment we ignore the other one.
We arenāt good at dialectical thinking. The way I tackle it is to keep asking myself the fundamental question. That should produce the major control theme and then the caveats are secondary..
The issue Iām describing really comes down to where the schedules are stored. With the push button timers they are stored on the timer. With the smart things the schedules are stored in the cloud.
I am happy to use the smart devices on the backed up circuits, but I have to cater for outages if I use them on non-backed up circuits. So the push button timers are better suited to that job.
Which spoils the fun for me a bit, but there you go.
The alternative seems to be to disappear down the Home Assistant rabbit hole, but thatās not the work of a few minutes.
Standalone controllers were the first to be used. Then in larger systems the signals to/from the field were managed by a central controller which had sophisticated visualization for those who ran the facility. Reliability was very important and wireless signals were never accepted in my day.
These days the voltage used for signals (I/O) and for powering controllers etc. is 24V dc. (which is backed up of course)
Iām a believer in delving into the history of a specific subject because it provides one with a better understanding of that subject. If one looks back into the history of control systems they only came of age when electricity was being deployed in every field there was.
Initially relays were wired up as the āāintelligenceā of control systems. Factories had banks of relays hard wired to perform a dedicated function. This system became difficult to maintain and to modify. So as electronics became more powerful these hardwired systems were migrated to āprogrammable logic controllersā which still used relays to switch things on/off but the logic was managed by electronic ICs.
