Solenoid valves

[NanLaew]

There's been a few threads of late relating to the standard water tank and pressure pump systems needed here.

 

I have a 'standard' storage tank and pump system that works well until the power goes off. The recent threads have got me thinking about adding the simple bypass pipework and check valves needed to get city pressure water bypassing the pump and tank system for these short, fai dahp periods. Nobody needs to take a shower but toilets need to be flushed! Also, to keep it simple for the other, less-motivated home dwellers, I would like it to be as automated as possible and remove the risk of some indolent soul not bothering to re-open/re-close gate valves once the power come back on, water overflowing, pumps running dry, huge water bill, etc..

 

Non-return valves are easy enough to get and I know where to put them but I am pondering a normally-open 220V solenoid valve on the feed to the tank and T-connected just before it, a normally-closed 220V solenoid valve for the pump bypass. The power goes off and the N/O valve de-energizes and shuts off the feed to the tank and the N/C valve de-energizes and opens up the bypass line.

 

Anyone seen suitable 1/2" 220V AC solenoid valves of both flavors on their shopping trips?

 

Thanks!

NL

[RideJocky]

I know solenoid valves are available on lazada. 
 

What’s the point of turning off water to the tank? Installing a check-valve that bypasses the tank and pump in the event of a power out will do it. 
 

Is the pump before or after the tank? 

[grollies]

I use these, available 1/2", 3/4", 1"

 

Find a pneumatic tool/fittings/equipment supplier although the box states suitale for pneumatic, liquids, etc. I use them on my water tanks in conjunction with a float switch for automatic filling of tanks. Thing is, they are normally closed so probably no use for your application in a power cut. Maybe they do them normally open, never asked.

[sometimewoodworker]

3 hours ago, NanLaew said:

I am pondering a normally-open 220V solenoid valve on the feed to the tank and T-connected just before it, a normally-closed 220V solenoid valve for the pump bypass. The power goes off and the N/O valve de-energizes and shuts off the feed to the tank and the N/C valve de-energizes and opens up the bypass line.

That seems overly complex when a few non return valves and a ball valve will perform exactly the same job without needing any power.

 

But not my circus, not my monkeys

[NanLaew]

2 hours ago, RideJocky said:

I know solenoid valves are available on lazada. 

I know but some that are labeled Normally Open are further described as NC (Normally Closed) in the details. Since they are coming from China, it would be a chore to wait longer for the wrong thing to be delivered.

 

2 hours ago, RideJocky said:

What’s the point of turning off water to the tank? Installing a check-valve that bypasses the tank and pump in the event of a power out will do it.

City water pressure can be low so shutting off the tank feed would ensure it's all going into the tank/pump bypass line. The tank/pump bypass line would have the check valve in it if I was trusting to simple manually operated gate valves instead of solenoids but I wish to avoid that for the reasons stated in the OP. I will put a check valve on the outlet of the pump before the T-connection with the bypass though.

 

2 hours ago, RideJocky said:

Is the pump before or after the tank?

The pump is on the outlet side of the storage tank and pressurizes the single-floor house plumbing which is reckon is 'standard'.

[NanLaew]

2 minutes ago, sometimewoodworker said:

That seems overly complex when a few non return valves and a ball valve will perform exactly the same job without needing any power.

 

But not my circus, not my monkeys

Whats overly complicated when the loss of power automatically actuates the two valve solenoids simultaneously and when power is restored, the valve solenoid action automatically reverses? Nobody has to A ) go and turn any ball valves, or B ) forget to go and swap them back, or C ) forget which one does what.

 

I want it to be as idiot proof as possible for those that are left unsupervised. You know what Isaan folk can be like.

[NanLaew]

45 minutes ago, grollies said:

I use these, available 1/2", 3/4", 1"

 

Find a pneumatic tool/fittings/equipment supplier although the box states suitale for pneumatic, liquids, etc. I use them on my water tanks in conjunction with a float switch for automatic filling of tanks. Thing is, they are normally closed so probably no use for your application in a power cut. Maybe they do them normally open, never asked.

 

A friend of mine has a water factory and I know he was always chasing for quality valve solenoids as they get heavy usage at his plant. I'll see what he suggests.

 

Thanks.

[mogandave]

18 minutes ago, NanLaew said:

Whats overly complicated when the loss of power automatically actuates the two valve solenoids simultaneously and when power is restored, the valve solenoid action automatically reverses? Nobody has to A ) go and turn any ball valves, or B ) forget to go and swap them back, or C ) forget which one does what.

 

I want it to be as idiot proof as possible for those that are left unsupervised. You know what Isaan folk can be like.

Using a single check valve (walve?) in the bypass (from before the tank to after the pump) will work automatically and without interuption. 
 

The tank has a ballcock yes? There is no need to shut water off to it. Even if the tank is empty, everything lower than the ballcock will get water, even while the tank is filling. 

 

How long does it take to fill your tank? It should stay pretty full, so even if someone is in the shower when the power goes off, it should top off pretty quick. 
 

Finally, if you do go with s NO valve and the coil burns out, you will (likely) have no water going to your tank and you won’t know it until the tank is empty and the pump has overheated...

[NanLaew]

21 minutes ago, mogandave said:

Using a single check valve (walve?) in the bypass (from before the tank to after the pump) will work automatically and without interuption. 

Makes sense, thanks. Do you think inserting another check valve to prevent back flow from the bypass into the outlet side of the pump is overkill? Or will equalized pressures in the closed, static, pump-side of the system eventually prevail?

 

24 minutes ago, mogandave said:

The tank has a ballcock yes? There is no need to shut water off to it. Even if the tank is empty, everything lower than the ballcock will get water, even while the tank is filling. 

 

How long does it take to fill your tank? It should stay pretty full, so even if someone is in the shower when the power goes off, it should top off pretty quick.

Yes it has. There are actually two tanks about 2,000 liters each plumbed in parallel but with the inlet (with ballcock) and outlet on the same tank. The last time we drained them for cleaning, they refilled overnight but no way of telling if mains pressure was constant though. With a full house, kitchen, wet bar, two bathrooms and a busy washing machine, we haven't managed to run them dry yet!

 

41 minutes ago, mogandave said:

Finally, if you do go with s NO valve and the coil burns out, you will (likely) have no water going to your tank and you won’t know it until the tank is empty and the pump has overheated...

Good point. I would need to figure out some other float-based system that shuts off pump power when the tanks get too low and install that in the other tank. Then hopefully the overall, visible loss of pressure in the house when the system slips into bypass mode while there's still power in the rest of the house would alert the residents that something was amiss out the back. I recall seeing something like that in another water pump related thread.

 

Thanks.

[sometimewoodworker]

2 hours ago, NanLaew said:

Whats overly complicated when the loss of power automatically actuates the two valve solenoids simultaneously and when power is restored, the valve solenoid action automatically reverses? Nobody has to A ) go and turn any ball valves, or B ) forget to go and swap them back, or C ) forget which one does what.

 

I want it to be as idiot proof as possible for those that are left unsupervised. You know what Isaan folk can be like.

The very fact that you are using power when NRV’s and an automatic ball valve can do exactly the same job with no power involved.
 

No manual valves are needed ( the ball in a ball valve is a float) Nobody has to do anything.

 

If your system requires a shutoff valve to function then it has been designed in a less than optimal way.

 

Our water system will happily function for several days with no power and no village water supply, virtually indefinitely with village water but no power. There are no shutoff or manual valves needed for that, it just works.
 

The 75kl backup is always full until the village supply is cut for more than a couple of days, the immediate use 1kl tank is filled either by the village supply pressure or if that is cutoff then pumped from the reserve. I do nothing to switch over it’s completely automatic. 
 

A couple of months ago our neighbors asked if we were okay for water as the whole village had had the water supply cutoff for about 10 days, we had no idea that the water was off as our system was working perfectly the only effect was that the reserve was down to 65kl.

[maxpower]

9 hours ago, NanLaew said:

Non-return valves are easy enough to get and I know where to put them but I am pondering a normally-open 220V solenoid valve on the feed to the tank and T-connected just before it, a normally-closed 220V solenoid valve for the pump bypass. The power goes off and the N/O valve de-energizes and shuts off the feed to the tank and the N/C valve de-energizes and opens up the bypass line.

 

Normally open valve on the tank feed line, normally closed valve on bypass line. Results at power loss = tank feed line open, bypass line closed.

Valve coils energised 24/7, be sure to stock spare coils.

[RideJocky]

10 hours ago, NanLaew said:

Makes sense, thanks. Do you think inserting another check valve to prevent back flow from the bypass into the outlet side of the pump is overkill? Or will equalized pressures in the closed, static, pump-side of the system eventually prevail?

 

Yes it has. There are actually two tanks about 2,000 liters each plumbed in parallel but with the inlet (with ballcock) and outlet on the same tank. The last time we drained them for cleaning, they refilled overnight but no way of telling if mains pressure was constant though. With a full house, kitchen, wet bar, two bathrooms and a busy washing machine, we haven't managed to run them dry yet!

 

Good point. I would need to figure out some other float-based system that shuts off pump power when the tanks get too low and install that in the other tank. Then hopefully the overall, visible loss of pressure in the house when the system slips into bypass mode while there's still power in the rest of the house would alert the residents that something was amiss out the back. I recall seeing something like that in another water pump related thread.

 

Thanks.

I think the second check-valve is redundant as the pump works as a check-valve.

 

You should have, and probably do have a check valve between the your meter and your tank. 
 

I would go with the check valve and forget the solenoid valve.

[Fruit Trader]

The N.O. N.C. valve arrangement in the O.P. is incorrect for the operating description given as pointed out in post 11. N.C. should be on the tank feed N.O. on bypass.

 

Non return valves are the best solution for auto pump and tank backup unless there is reason to only feed the property directly from public supply during power failure. If this is required, one or two valves will be constantly energised during normal operation. Not the best long term solution.

[Fruit Trader]

12 hours ago, NanLaew said:

Makes sense, thanks. Do you think inserting another check valve to prevent back flow from the bypass into the outlet side of the pump is overkill? Or will equalized pressures in the closed, static, pump-side of the system eventually prevail?

Because many automatic pumps have their factory fitted non return valve on the inlet, an additional non return valve is sometimes added to a pumps outlet to protect front end seals from high pressure pulses on public supply. Pumps with open pressure tanks are the most vulnerable to excess pressure applied to their inlet.

[NanLaew]

15 hours ago, sometimewoodworker said:

The very fact that you are using power when NRV’s and an automatic ball valve can do exactly the same job with no power involved.
 

No manual valves are needed ( the ball in a ball valve is a float) Nobody has to do anything.

 

If your system requires a shutoff valve to function then it has been designed in a less than optimal way.

 

Our water system will happily function for several days with no power and no village water supply, virtually indefinitely with village water but no power. There are no shutoff or manual valves needed for that, it just works.
 

The 75kl backup is always full until the village supply is cut for more than a couple of days, the immediate use 1kl tank is filled either by the village supply pressure or if that is cutoff then pumped from the reserve. I do nothing to switch over it’s completely automatic. 
 

A couple of months ago our neighbors asked if we were okay for water as the whole village had had the water supply cutoff for about 10 days, we had no idea that the water was off as our system was working perfectly the only effect was that the reserve was down to 65kl.

I see we have a nomenclature conflict. Never mind, I still know what we're both talking about.

 

It wasn't designed or installed by me so you are 100% correct in stating the obvious that it 'less than optimal'.

 

I am happy that you are self sufficient.

 

Thanks anyway.

[NanLaew]

4 hours ago, Fruit Trader said:

The N.O. N.C. valve arrangement in the O.P. is incorrect for the operating description given as pointed out in post 11. N.C. should be on the tank feed N.O. on bypass.

 

Non return valves are the best solution for auto pump and tank backup unless there is reason to only feed the property directly from public supply during power failure. If this is required, one or two valves will be constantly energised during normal operation. Not the best long term solution.

Yes, I noticed I had my NO and NC ass about tit but too late to edit. Thanks for the confirmation.

 

4 hours ago, Fruit Trader said:

Because many automatic pumps have their factory fitted non return valve on the inlet, an additional non return valve is sometimes added to a pumps outlet to protect front end seals from high pressure pulses on public supply. Pumps with open pressure tanks are the most vulnerable to excess pressure applied to their inlet.

The non-return valves seem to be the easiest 'passive' solution as my mate with the water factory does say the overall quality and longevity of solenoid valves purchased locally is iffy even with his super-regulated local power supply. He usually stocks up with spare ones from Lowe's when he's back in the US.