Solenoid Failure?

[Kiko]

My parents had a ventless gas log system installed in their fireplace 3 yrs ago, purchased from Lowes. The main burners are ignited by a solenoid located in the gas valve. This solenoid is powered by a remote controlled receiver box wired to the solenoid, which takes 4 AA batteries (six volts).

The burners stopped working and did not work even after fresh batteries were installed in the remote and the receiver. I disconnected the wires to the solenoid and used my voltmeter to check the voltage coming from the box. It read 6 volts in both the "on" and "off" positions, which means the solenoid should be able to open and close, if working properly. I then touched the solenoid wires to the terminals of a 9 volt battery, and the solenoid opened and closed and the burners turned on and off.

I lined up 5 AA batteries (7.5 volts) and the solenoid still worked fine. However, when I removed one of the batteries, the solenoid turned off the burners but would not turn them on unless I increased the voltage.


I have four questions:

1. Why would the solenoid work in one direction, i.e., close, but not open, with 6 volts?

2. Why would increasing the voltage to 7.5 volts allow it to open and close, when it is designed to open and close with 6 volts?

3. Does a solenoid wear out slowly, or does it go all at once?

4. Is there a way to add an additional battery to the receiver, so I don't have to mess with trying to replace the solenoid, if the solenoid is defective?

[jwelectric]

1. Why would the solenoid work in one direction, i.e., close, but not open, with 6 volts?
I would guess that it would close without any voltage but not being familiar with the unit I can’ say. I have a gas heater that shuts off the gas during any power failure.

2. Why would increasing the voltage to 7.5 volts allow it to open and close, when it is designed to open and close with 6 volts?
It could be due to an increased resistance in the winding

3. Does a solenoid wear out slowly, or does it go all at once?
It can go either way, slowly or all at once

3. Is there a way to add an additional battery to the receiver, so I don't have to mess with trying to replace the solenoid, if the solenoid is defective?
I am not sure that this would be a good idea

[jadnashua]

Some valves have a spring in them, so that can help (often to turn it off) one direction verses the other. It depends on the design. To save power, in this application, it probably swaps the voltage, and it stays (i.e., isn't sprung). The gaskets or bearing that the valve slides through could be worn or corroded.

[DonL]

If you are only getting 6 Volts from 4 AA Batteries,
Then your batteries are not all that Fresh.

Good Alkaline batteries will be higher than 6.

1.5 V No Load => 50% Dead

[Kiko]

If you are only getting 6 Volts from 4 AA Batteries,
Then your batteries are not all that Fresh.

Good Alkaline batteries will be higher than 6.

1.5 V No Load => 50% Dead

I was just trying to keep things simple. The four brand new alkalines measured ~6.6 V.

[Kiko]

Some valves have a spring in them, so that can help (often to turn it off) one direction verses the other. It depends on the design. To save power, in this application, it probably swaps the voltage, and it stays (i.e., isn't sprung). The gaskets or bearing that the valve slides through could be worn or corroded.

The way the receiver box works is that it puts out current in one direction to open the solenoid and reverses the current to close it. I assume this would cause the electromagnet to open and close some kind of ferrous "gate," possibly separate from the valve itself, since the gas valve is maintained in the "open" position at all times with only the pilot flame burning.

Not sure if a spring is involved. My uneducated opinion is that the windings are okay, since the solenoid works in one direction. Perhaps the "gate" gets stuck when trying to open it because something is worn or corroded (as you mentioned.)

[Kiko]

One final thing. At some point in this "experiment," I wire-nutted in a couple of additional feet of 18 gauge wire to allow the remote box to sit outside of the fireplace (so I wouldn't have to bend over so much).

How can I determine the voltage drop caused by that additional wire?
The initial voltage is 6.6 volts DC and the wire gauge is 18. I don't know what the amperage or the wattage is, but I assume a 6V DC solenoid has a certain wattage rating. I just can't find it.

[DonL]

One final thing. At some point in this "experiment," I wire-nutted in a couple of additional feet of 18 gauge wire to allow the remote box to sit outside of the fireplace (so I wouldn't have to bend over so much).

How can I determine the voltage drop caused by that additional wire?
The initial voltage is 6.6 volts DC and the wire gauge is 18. I don't know what the amperage or the wattage is.

Without knowing the current then you would just have to measure the Voltage.

I don't think that it would be very much, If you just added a couple feet.

Is it possible that your control box has a bad capacitor in it ?
If it has one you may want to check it.

[BobL43]

One final thing. At some point in this "experiment," I wire-nutted in a couple of additional feet of 18 gauge wire to allow the remote box to sit outside of the fireplace (so I wouldn't have to bend over so much).

How can I determine the voltage drop caused by that additional wire?
The initial voltage is 6.6 volts DC and the wire gauge is 18. I don't know what the amperage or the wattage is.

It can't be much current that is drawn, otherwise the battery life would be very short. I have a Vanguard unvented gas firelog that uses a 9 volt battery in the receiver/control and it lasts for several years. Seems unsafe that it would require a voltage to close the (main burner?) valve. the pilot valve is kept open by a themocouple pilot generator device. Hmmm. did you try to contact the manufacturer of this unit?

[Kiko]

Without knowing the current then you would just have to measure the Voltage.

I don't think that it would be very much, If you just added a couple feet.

Is it possible that your control box has a bad capacitor in it ?
If it has one you may want to check it.

The box is fine. It puts out 6.6 volts in both positions.
To measure the voltage at the other end requires unbolting the unit from the fireplace floor and removing all the logs to get to the solenoid.

[Kiko]

It can't be much current that is drawn, otherwise the battery life would be very short. I have a Vanguard unvented gas firelog that uses a 9 volt battery in the receiver/control and it lasts for several years. Seems unsafe that it would require a voltage to close the (main burner?) valve. the pilot valve is kept open by a themocouple pilot generator device. Hmmm. did you try to contact the manufacturer of this unit?

The manufacturer is Pro Com, and they haven't been very helpful in either diagnosing the problem or sending replacement parts (still under warranty.)

The remote/receiver is made by SkyTech and they don't make a 9 volt receiver.

I bought some battery holders and may try to add an additional AA battery or replace them all with a 9 volt and see if that will work. I may also just replace the remote with a rocker switch hooked up to a 9 volt if I can find one that puts out current in both the on and off positions. BTW, is there a special name for a switch like that? The good folks at Radio Shack never heard of one.

[jadnashua]

An on/off switch just opens in the off position, otherwise, it wouldn't be an on/off switch.

What likely happens in what you have is they swap the polarity of the voltage in one position verses the other, and in the 'off' position, it disconnects it entirely; otherwise, the circuit would be drawing power all the time, and the battery life would be lousy.

Is it a rocker switch, with a 'center' position?

[Kiko]

The box has three positions: On, off, and remote. When you slide the switch to "on" it puts out 6.5 volts for two seconds to open the solenoid. When you slide it to "off" it swaps polarity and puts out 6.5 volts for two seconds to close the solenoid. In the "remote" position it does the same thing using the remote control buttons to switch on and off. Since it only draws current for a couple of seconds, the batteries last a year or more.

[jadnashua]

It's likely a simple switch, but it's an input to an active circuit...i.e., there's a chip in there that's setting up the timing and likely the voltage polarity swap. You can duplicate the function, but it would be up to you to manually make the requried on/off pulse. Keep buggin the manufacturer, as they're the best source to help, especially if it is still under warranty.

[Kiko]

I've been dealing with the manufacturer for three weeks now, and they keep finding new hoops for me to jump through.

My idea of adding an additional battery in series with the others may work, but I'm not sure if the added currrent will fry the circuit board.