Propane cook tops

PDQ issues applicable across all PDQ Yachts (or if you can't find a place for something, it probably belongs here for now)
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ELIXIR
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Propane cook tops

Post by ELIXIR »

I have a periodic problem with the 2 burner propane burners lighting off on my PC34.
It is inconsistent and seemingly unrelated to when last used, i.e. time for gas to reach stove after long disuse. When pushing down on the burner control to light it at times it will not light despite repeated and/or prolonged attempts. Other times lights immediately. Any suggestions?
Jim Stalnaker
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Post by duetto »

is it both burners or just one?

ours would light but not stay lit. turned out to be a melted knob. bottom was deformed and not flat. i filed flat until we got new ones.

other thing, is that in cold weather it takes longer to light.

good luck.
john & diane cummings
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Mishigas
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Post by Mishigas »

Going off memory here but we had a similar problem. If I can remember correctly, you have to also depress the button down while you ignite the burner, not just ignite. Then continue to hold button for 10 seconds or so and you can let go.
Sandy K
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ELIXIR
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Post by ELIXIR »

both burners and fully depressed but still doesn't light at times. Not apparently temperature related either. Other suggestions
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Ed Ellis
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Post by Ed Ellis »

First, make sure your tank is not almost empty. That can cause similar symptoms.

Second, I'd check for leaks in the system. That would definately cause the delay in gas reaching the stove. Most likely the leak will be in the locker where the tank is stored. If you smell rotten eggs, there's a good chance that one of the connections is loose. Make sure the white teflon plummer's tape was used at each connection. It should be obvious just looking at the connections.
Do you have a propane gas detector/alarm installed?

Next I'd check the electric switch to the gas solinoid.

1. Turn off gas at tank.
2. Disconnect hose from solinoid on the tank side of it.
3. With a flashlight, look inside the solinoid as someone else turns the switch off and on. You should see the valve inside open and close and hear it click simultaneously with the switch.

If you find any delays between the switch being thrown and the valve opening/shutting, you may have a bad switch or solinoid. Most likey the switch.

Good luck, Ed
Ed & Linda Ellis
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Post by duetto »

is prezo snapping when knob is depressed?

also, you say "at times". that would imply that it works ok other times....is that true?
john & diane cummings
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Post by duetto »

hi,

thought of something else to check. we had a tank that had too much air in it, rather than propane. if you have a spare tank try swapping. if not borrow a 20lb grill tank and see if problem occurs/ersists.
john & diane cummings
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Post by duetto »

hi jim,

nice article in power cruising.
john & diane cummings
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Gadzooks!
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Post by Gadzooks! »

We had lots of trouble getting with the cooktop lighting. Sometimes very slow, sometimes impossible. Removed the cooktop, had it checked out by an expert, it worked fine. Replaced the solenoid - no improvement. Believe the trouble sprang from the "honey" that sometimes precipitates out of the propane. It is a brownish viscous liquid. It gums up the solenoid. I turned the solenoid so it was above the gas line, instead of below as originally. And have had no trouble since. The stove lights every time, with no delay. My theory is that, as the solenoid normally runs hot, it reduces the viscosity of the "honey", so that it flowed down into the solenoid, clogging it. With the solenoid above the gas line, the honey will tend to flow out of the solenoid, keeping it clear.

I'd be interested in hearing about any further developments in your case.
Mebs and Wally Gilliam
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Post by duetto »

hi,

for future reference, where is solenoid located and how do you get at it?
john & diane cummings
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Post by Gadzooks! »

On our boat, and probably on all the MV34s, the solenoid is in the propane locker under the curved built-in seat on the port side next to the flybridge helm station. It is only a couple inches in size, and has threaded fittings connecting it with the gas lines fom the regulator and to the stove. And a wire to supply power. To get space to work, it is best to remove the propane bottles from the locker.

If you detect any precipitated "honey", it can be cleaned up with alcohol. I also took the line to the stove off at both ends, poured alchol thru it and blew thru it. It was clear. Earlier, I replaced the pressure regulator (also at the propane bottles - it's disc shaped, looks like a tiny spaceship Enterprise. ) I'm not sure there was any problem there, and it did not solve the stove lighting problem, but there was some honey in evidence, and the regulator is not expensive.

I replaced the solenoid ($70 from the manufacturer. I don't remember which company, but it is printed on the solenoid housing.) but probably could have cleaned out the old one. I'd suggest washing it in alcohol then heating it in an oven (low heat) with the opening down so any residual honey will melt and run out.

Our solenoid was originally installed below the gas line. I don't know whether all are that way. If yours is, quite possibly it would only be necessary to twist the solenoid around to a position above the gas line. If there is not too much honey, the heat generated by the solenoid when it is on would probably be enough to cause the honey to melt and run down and out, leaving the solenoid free to operate. Perhaps worth a try before you disassemble.

Be sure to check the system for leaks after doing any work on the connections. With the stove off, turn the propane bottle on, so that you get a reading on the pressure guage (at the regulator) which reads the pressure in the gas line. Then close the bottle. The pressure should remain high for at least 24 hours. Any leak will cause the pressure to drop. You can also sniff around. I don't have a propane detector in the galley, but it is a good idea.
Mebs and Wally Gilliam
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Post by Gadzooks! »

Re: Pressure testing:

I forgot to mention--- When you test for leaks, as described previously, the solenoid should be ON. This way, the line all the way from the bottles to the stove will be under pressure, and leaks should be reflected by falling pressure readings. With the solenoid OFF, only that portion of the line from the bottle to the solenoid will be under test.
Mebs and Wally Gilliam
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Post by Stray Cat »

I solved this exact problem on my Princess cooktop. The fix was suggested in a sketch and note I got when my boat (hull MV34 #12) was picked up at the Whitby.

It seems that the plastic knobs got pressed too far onto their shaft and distorted when I put something heavy on top. Or perhaps the knobs were damaged by hot gasses when I used a large pot or pan. Gently lift one or both knobs off their shafts and peer down at the little button alongside the main shaft. That precious little button is the switch for the igniter. When your knob presses down on the little button to run the igniter, it must also press down the main shaft the right amount to bypass the flame detector in each burner and supply gas during the start, even though the flameout detecting thermocouple in the burner is cold. The key here is that the igniter button action and the amount the main shaft is pressed down have to be coordinated properly, and with the knob pressed too far down the shaft, the igniter was running fine, but the gas was not being supplied. You can sniff test for gas AFTER you have tried starting the burner for a while. If you sniff the burner DURING an attempt to light it, you risk an instant shave and haircut, to say nothing of a painful burn!

The fix is gloriously simple. I lifted each knob off its shaft and installed a steel washer a millimeter or so thick which fit nicely around each main shaft, and with an outer diameter large enough to reach the small button alongside the main shaft. Original performance restored.

Sometimes in cold weather my solenoid sticks closed, and I have to go up and give it a couple of taps. If I have not used the system for a long time, the lines will have bled off the gas in them, and it takes a little time to get gas all the way back down to the stove.
Candy Chapman and Gary Bell in Stray Cat, MV34 hull 12
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