Positive or negative, only two black wires

[Tmacmi]

I am replacing the regulator for the propane system.

There are two black wires coming from the solenoid. How do I tell which is positive or negative?

Or does it matter in this application?

[goboatingnow]

Doesn’t matter

[boatpoker]

Most of the time, two black wires just indicate that the appliance is not polarity sensitive.

[Dave_S]

AC or DC ?

The coils will work on both regardless of polarity except a DC coil should have a diode across it to contain back EMF, which will make it polarity sensitive (one way will work, the other won't). Exceptions to this are latching solenoids which may have a transorb, and one polarity will retract it and one will release it.

[goboatingnow]

Originally Posted by Dave_S

AC or DC ?



The coils will work on both regardless of polarity except a DC coil should have a diode across it to contain back EMF, which will make it polarity sensitive (one way will work, the other won't). Exceptions to this are latching solenoids which may have a transorb, and one polarity will retract it and one will release it.

I’ve not seen a solenoid gas valve that has a diode in it from manufacture ?

[tkeithlu]

Hey, it's a simple coil solenoid. It's DC. It will work either way.

[Dave_S]

Originally Posted by goboatingnow

I’ve not seen a solenoid gas valve that has a diode in it from manufacture ?

I don't understand, why would they not use one ?

I would assume it would be mandatory on gas systems.

[boatpoker]

Originally Posted by Dave_S

I don't understand, why would they not use one ?

I would assume it would be mandatory on gas systems.

There are no "mandatory" propane codes in the US or Canada for pleasurecraft and no solenoid I've ever seen has a diode. It's also not required in ABYC Standards.

[Dave_S]

Originally Posted by boatpoker

There are no "mandatory" propane codes in the US or Canada for pleasurecraft and no solenoid I've ever seen has a diode. It's also not required in ABYC Standards.

This PDF claims to be referencing ABYC, sorry, I don't know much about US and Canada regs but this is from "Caltrans" (seems legit) and appears to state that solenoid coils must have suppression from back EMF.

[boatpoker]

Originally Posted by Dave_S

This PDF claims to be referencing ABYC, sorry, I don't know much about US and Canada regs but this is from "Caltrans" (seems legit) and appears to state that solenoid coils must have suppression from back EMF.

The (Caltrans)California Department of Transport (?) has nothing to do with pleasurecraft standards.

Cantrans says simply ...
"• Boats and aquatic craft used by Caltrans shall meet the A.B.Y.C "Standards and
Technical Information Reports for Small Craft"


If you message me an email address I'll respond with pdf's of the appropriate standards

[Dave_S]

Originally Posted by boatpoker

The (Caltrans)California Department of Transport (?) has nothing to do with pleasurecraft standards.

Cantrans says simply ...
"• Boats and aquatic craft used by Caltrans shall meet the A.B.Y.C "Standards and
Technical Information Reports for Small Craft"


If you message me an email address I'll respond with pdf's of the appropriate standards

It might be best to post the standards here, I'm only interested to the point that I do not believe the US or Canadian standards would not require suppression across solenoid coils. You may be right but I'll be surprised that the regulations permit bad practices.

My concern is that these posts imply to others reading this that diodes are not needed.

[boatpoker]

Originally Posted by Dave_S

It might be best to post the standards here, I'm only interested to the point that I do not believe the US or Canadian standards

What do you mean 'US or Canadian Standards" ?
There are no legally required rules for propane on pleasurecraft in Canada or the US.

Legal requirements for pleasure craft in Canada are found TP1332
Legal requirements for pleasurecraft in the US are found in Title 33,CFR

Neither of these mentions propane.

CFR Title 46 sub part 25.45 which applies only to commercial ("uninspected")vessels does state that ABYC Standards must be applied.

[Lake-Effect]

In a past life (broadcasting), we put snubber diodes on every DC-energized coil - mostly relays - but that was mainly to suppress the EMF 'snap' that would otherwise be emitted when the coil power was removed. The diode also reduces arcing at whatever switch or device is upstream. But perhaps in a marine propane installation, the EMF spike and the added switch wear aren't significant concerns.

[boatpoker]

Originally Posted by Lake-Effect

In a past life (broadcasting), we put snubber diodes on every DC-energized coil - mostly relays - but that was mainly to suppress the EMF 'snap' that would otherwise be emitted when the coil power was removed. The diode also reduces arcing at whatever switch or device is upstream. But perhaps in a marine propane installation, the EMF spike and the added switch wear aren't significant concerns.

Could be that ... or simply that propane solenoids are ignition proof (technically "explosion proof).