Had a close call with my well pump today !

[Arky217]

You know how that when a pump stops, there is usually quite an arc
across the contacts of the pressure switch. After an extended time
of arcing, switch contacts have been known to weld shut, thus not
allowing the pump to stop when the cutoff pressure is reached.

Well, a couple of months ago I was researching about putting an R/C
snubber across the contacts to reduce the arcing because I noticed
that the contacts were starting to pit somewhat.
In my searching, I came across an ad about a product called NOsparc that
is supposed to completely eliminate the arcing.

Purchased one and installed it. I tested it in the dark to see if
I could see any arcing at all and it seemed to work as indicated;
I just barely could see a spark in the dark.

Well, fast forward 2 months later.
I had just went outside when I heard a whining noise; I thought it
was the hum of a distant piece of machinery.

A few minutes later, wife opens the door and says, "what is making
that noise". Soon as she opened the door, I realized that the noise
was coming from inside the house. I ran to the pump room where the
noise was and first thing I noticed was that the pressue gauge was
reading 95 psi and still climbing. I immediately killed power to
the pump. The pressure started to drop but the noise continued.
Then I realized that the noise was the overpressure valve
venting the water.

After the pressure dropped to the cut-on point I removed the switch cover
and turned power back on to the pump. When the cut-off point was
reached, the contacts opened but the pump still ran.

I thought,"that's impossible", then I realized that the only way
the pump could still get power was through that NOsparc suppressor.

Removed the NOsparc, then everything was fine.

I shudder to think what might have happened if the pump had continued
to run. I had no idea the pump would even build to 95 psi and it was still
climbing higher even with the overpressure valve open.

So, here's a product that caused exactly what it was supposed to prevent!

Thought a warning was in order in case anyone has installed this or a
similar product across the contacts of your pump's pressure switch.

Arky

[rick91351]

We plumbed ours in with a pressure relief valve.  It loops around and if active empties into a floor drain also used by the heat pump.

[Don_P]

Not well related but to switches arcing and sticking on... my Makita skillsaw switch failed in the on position yesterday. This is the 3rd or 4th one I've had this happen to over the years, they always fail in the on position. Let go of the trigger and the saw continues to run. It was a little unnerving the first time. It's happened enough that I keep a spare switch in the shop.

[Tickhill]

DC will arc considerably more than AC. Installing a properly rated disconnect (knife switch disconnect) on the line side of the contacts as a safety is always advised, it can be used for lockout/tagout if work needs to be done to the DC device.

[Dave Sparks]

I have to ask if you are using the correct switch? This should not happen if you are. The contacts generally fry in the open position. If you are using something not rated for the job, all bets are off.