SPRINKLER TALK FORUM - You Got Questions, We've Got Answers

After reading and re-reading the manual, I'm left unsure
if start time stacking works on single station valves? On
page 10 on the manual, mention is made of stacking for
multiple valves - not one valve.

The manual declares that the maximum run time for the
SVC-100 is 4 hours. Can I set two start times on a single
station SVC, four hours apart, with a run time of four
hours, in order to get an aggregate run time of 8 hours?

Anyone have any experience with this?

Right. In most cases, I can factor in a decent break between on and off,
by a major re-arrangement of the station/zone sequences. But in one
valve, only the (minimum) five minute segment could be allowed in the
program 1 end and program 2 start time setting of the SVC-100.

As fortune would have it, I've been beavering away at getting this all
into sufficient order so that I could go away for five days, without new
grass (seeded 3 weeks ago) getting burnt off. The arrangement is unduly
complex (for me), and taken quite a lot of adjustments to get right.

Trouble is, I can't be sure it's right by observation, because it's rained
on and off for the last several days. Still is, as I type this reply! Which
brings me to another question about a PMV setting.

Instead of any rain sensor or the like, if a shut off valve is manually
closed between the master solenoid valve (water supply, not pump)
and the irrigation system, can any harm occur if that's done, with no
changes being made to the programming of the field controllers?

I.e. will they just go through their open-and-close valves sequences,
with no water available/flowing, and no harm coming to the valves
or controllers, as a consequence?

Quoted from "mrfixit"

You have me a little bit confused here. If you're using the SVCs in the field, what's controlling the master valve?

A separate electronic timer in the pump shed. The system is a hybrid.
One with a few design flaws. (Wet Boots is not so charitable!) The
pump supplies domestic water via a very large pressure tank, with
water fed to five households. The pump shed timer simply opens
the solenoid valve to the irrigation system. Brief, initial water flow
is from the pressure tank. When the pressure drops far enough, the
pressure switch on the tank starts the pump.

When all the in-field cycles are completed, the pump shed timer
closes the solenoid valve to the irrigation system, as it proved to
be unable to cope with the static pressure required to make the
gear heads function correctly. Two ruptures happened in the week
before I added that irrigation field open/close function. Same
irrigation field system fills header tanks connected to drinking
troughs for two flocks of free range hens, so the residual pressure
in the pipes is abated by thirsty hens, not long after the pump
shed timer closes the solenoid valve to the irrigation field system.

Quoted from "mrfixit"

To answer your question, no harm would come to the controllers. The DC solenoids don't get hot like AC.

Right. Thanks. Does that imply that standard 24v AC valve solenoids
are at risk from what I described? Those are presently programmed
to work daily, for 40 minutes. But if the 2 inch ball valve is closed,
in the pump shed, those valves will open and close despite there
being no water to control.

Quoted from "mrfixit"

OK. I wont be able to give you any more advice on this. I don't know the first thing about your pump and what will happen when it tries to run but you have a shut off valve on the line. Sounds like it might burn up to me.

The pump pressurises a tank, so switches on and off, automatically.
There is a solenoid valve and a ball valve in the line that connects
the tank to the irrigation line. When the solenoid valve opens, water
can flow to the field. But if the ball valve is closed, it only flows as
far as that - a few yards.

It's not until the pressure in the tank drops that the pressure switch
starts up the pump. When the pressure rises to a certain point, (say,
when the field irrigation has finished, that), the pressure switch
turns the pump off.

It's not what goes on at the well-head that I'm concerned and asking
about, it's what goes on, out in the field. Specifically the 24v AC
valves opening and closing at a time when no water flow is available.
I may have unwittingly distracted attention from that.

Thanks for the added comments. Following your advice,
the below-mentioned tactic will mean only DC latching
relays will be affected by no water supply.

Quoted from "Mitchgo"

My question is what event does the 2" ball valve need to be shut off for if you have a master valve?

I've ended up with something that can be fairly described
as a mish-mash. So be it. I now need to work with what
I've got, viz.
Pump controller (time switch)
SVC x 3
Galcon tap timer x 2
Irritrol controller

There is no way that I can see to do a centralised Rain/Off
arrangement, as the water supply feeds differ and the SVCs
and Galcons are scattered over the property.

Given your comments, I'll opt for turning the Irritrol to the
Rain/Off position and 'choke' the DC valves by denying them
water, by shutting off the ball valve. That's easier than
manually altering the PMV electronic timer to Off.

Quoted from "Mitchgo"

The debate for running solenoids with no water in the valve has been out for a while. While it does produce heat it more then likely won't harm much- at the most it will just lessen the life of the solenoid. Which in your situation isn't the biggest deal because solenoids are fairly cheap and you have to do this because of your unique situation.

Very tactfully put!

I have a spreadsheet with Pump controller (time switch),
Irritrol, SVC and Galcon sequences noted. It's taken quite
a while to get the diverse programming needs together,
so that it all works as it should.

If there's one thing that would be nice, with all such control
devices, is the common use of terms. E.g. set day x, M/W/F,
am/pm or 24 hour format, etc. Add in the varying time limits
on the devices, and it's a headache in the programming.

Well, this is what it looks like, now:


Clicking the little boxes to the right shows
a slightly larger pic. The woodlot at the back,
the apple orchard in front of it, and another
to the right (off pic) are all benefiting from
more regular, automated watering. As are
madam's gardens. I've even managed 6 days
away without any problems occurring.

Before that, the new (circa 65psi) higher
system pressure caused three pipe ruptures.
So I programmed the the PMV electronic
timer to activate the solenoid-to-the-field
valve a minute before any irrigation cycle,
and shut off a minute after. Stock drinkers
in the areas soon drop the field pipe pressure
to zero, between watering cycles.

Had some problems with the pump control
board, necessitating an expensive visit by
an electrician. The copper paddle in the
no/lo flow switch had almost eroded away.
I fashioned a replacement from stainless
steel. Also had a siren fitted for when any
fault condition shuts down the pump.

I'm sure Wet Boots will be scratching his
head in even greater amazement, but the
bill from the electrician's firm contained so
many mistakes! Just received a credit for
about $NZ1200. The original bill was $2096!

Unsurprisingly, I've told the crowd that did
the field irrigation installation (as depicted
in the pic) not to darken my driveway again.

I was going to put the pic in the other thread
named: Controller To Do Hybrid Switching
but the link says that thread has gone.
Wonder why?

Aside from showing the end desired result,
my other reason-for-posting is to again say
thanks to everyone who helped me resolve
all the problems I faced. It would have been
so much more difficult and time consuming
without that assistance. Especially from Wet
Boots, despite the somewhat acerbic tenor
of some of his observations, fair comment
and all, as they may've been, at the time.

If any forumite ever travels this way, send
me a PM or an e-mail , in case we have the
option of a get-together of some sort.

Next problem: sealing the pond and getting
water feature installed. Onward & upward!