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spencerin
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# Posted: 5 Feb 2024 21:33 - Edited by: spencerin
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Maybe an issue here? Just asking for free expert amateur advice before shelling out $ for expert services.....
I have a 20k BTU Martin direct-vent wall heater. It's hooked up to 2 100-gallon tanks.
It seems like it runs "empty" when one tank is empty but the other is half full. Is that possible? This has happened twice so far.
The switch-over device between tanks is automatic. When one tank is empty, a red dot appears on the device next to that tank.
When I was at my place this past weekend, the heater fired up fine, but at some point when I was outside, it apparently ran out of propane. I went to the switch-over device, but neither tank had the red dot. I tried to fire the heater back up, but just got occasional, momentary bursts of ignition, orange flame, nothing else. Try it again 60 seconds later, same thing....
Anyway, one tank is heavier than the other, so that's why I'm pretty certain both aren't depleted. Not to mention no red dots.
The heater, and other equipment, is less than 4 years old and barely used, installed by a certified HVAC company. What's making me question further is that I filled both tanks up about a year and a half ago, and didn't use them much. At least that I can recall. I did leave both tanks open, but the shut-off valve and heater knob closed, since fall. Possible leak?
Anyway, I'm just wondering if this is normal performance or not.....
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darz5150
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# Posted: 5 Feb 2024 21:46
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The regulator on my 100# tank will freeze over if it's really cold. How cold is it there?
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spencerin
Member
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# Posted: 5 Feb 2024 21:47
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It's been above freezing.
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spencerin
Member
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# Posted: 5 Feb 2024 21:50 - Edited by: spencerin
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Tanks are 100 lb., not 100 gal.....
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darz5150
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# Posted: 5 Feb 2024 21:57
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No clue then. When my pilot flame turns orange that means the tanks low.
If your pour some hot water on the tank, you should be able to feel where the lp level is.
Other than that, if you have a way to try a different regulator, try that. Good Luck.
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909
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# Posted: 5 Feb 2024 22:05 - Edited by: 909
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I have a similar Martin unit like yours. Just a smaller version, and installed a single regulator.
I upgraded from a standard BBQ regulator ( still works )
Notice the black cap. You can open that and adjust your regulator ( only a little at a time. CCW decrease and CW to increase ) . The vent should be pointed down. The regulator should be protected from the elements. To check for leaks use soapy water. As mentioned , try a different regulator ( or tank )
Martin also offers excellent support.
1 800-266-1414
8am to 6pm EST
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gcrank1
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# Posted: 5 Feb 2024 22:35
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I suggest you always shut the tank valves off when you leave.
The way lp works is the gas is made off the surface of the liquid in the tank, we use that gas. When too cold the reduced tank won't 'gas' as well, something about the ratio of surface area and upside volume?
Are you getting Butane or Propane? Butane gets touchy around 32*f, propane will go deeper.
Fwiw, when my dual setup would switch I always closed the valve on the empty one.
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Brettny
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# Posted: 6 Feb 2024 08:32
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I would suspect your change over device isnt working or the tank volume is to low to run the heater.
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ICC
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# Posted: 6 Feb 2024 10:24 - Edited by: ICC
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Ooops. i misread something so I edited. But I have a comment but can't find the data I want right now. Later...
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ICC
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# Posted: 6 Feb 2024 15:19 - Edited by: ICC
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Even if a 100 lb cylinder was only 10% full it should provide sufficient volume and pressure of propane for a 20K heater if the propane temperature is above freezing. That assumes proper diameter piping and average pipe run lengths.
If the heater did work on an almost full tank but not a tank with low level that would indicate a temperature or some sort of other pressure/volume issue.
See the table listed below.
My first thought would be the regulator could be at fault. The remote location of my cabin means it would be very difficult and costly to have a service technician come out. I have a spare regulator at the cabin as one winter I did have a regulator cease functioning. Cheaper to have a spare and more convenient.
FYI, when installing a regulator it makes sense to me to install it with a pipe fitting union rather than simply thread the run of pipe into the regulator. Then, if or when it must be serviced it can be easier to undo the union instead of having to spin the regulator to unthread from the pipe.
100# parallel cylinder connections
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ICC
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# Posted: 6 Feb 2024 15:22 - Edited by: ICC
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The table above is not mine. A friend made it years ago. He also made the following tables, which can be useful as well. I think they have been listed here before.
asst'd cylinder sizes
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vapor pressure & temperature
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properties
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spencerin
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# Posted: 6 Feb 2024 20:03 - Edited by: spencerin
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Thanks for the feedback. I think I'll have a pro come look at it. But, I suspect there is in fact a regulator, and/or switchover, issue, as suggested.
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Brettny
Member
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# Posted: 7 Feb 2024 10:27
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I would change the empty tank to a new and point the change over device to the new tank. If it dosnt light then call someone.
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gcrank1
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# Posted: 7 Feb 2024 16:39
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Imo, if the auto-switchover worked last time from tank to tank it did what it is supposed to.
You know the tank it was running on was/is low.
So you know you need at least one new tank for the rest of the winter.
My method was to get a new filled tank in place asap after a switch happened, always had fuel then.
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spencerin
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# Posted: 3 Mar 2024 20:33
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Well, I have 2 40 lb. tanks (I have no idea why I said they were 100 gal.) that I re-filled this weekend. It turns out both were only about 75% depleted, and the guy who re-filled them said there was a lot of air in both of them, which I watched him bleed off before re-filling. My guess is the air was never bled off when they were new and filled for the first time? I have no idea otherwise how that happened.
Anyway, I hooked them back up, the regulator no longer read empty and.....the heater wouldn't start at all. I must've tried for 20 minutes. I have no idea why not.....
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gcrank1
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# Posted: 3 Mar 2024 21:08
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I expect your tanks have OPD valves?
IME they can be troublesome because while you are trying to purge the gas line of air to get the stove control to work the OPD thinks it is a leak and shuts the valve off.
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spencerin
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# Posted: 3 Mar 2024 21:17 - Edited by: spencerin
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They have OPD valves, yes. I had no idea they existed and what their purpose was until you mentioned it (thanks, Google). I'll see about resetting those next time I'm there.
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ICC
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# Posted: 4 Mar 2024 12:17
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Are there other propane appliances like a range, cooktop, water heater, grill or whatever? I'm guessing that is a negative or would have likely said that the other things worked or also did not work. If all the pipe and hose connections were in place and the heater control valve set to off the purging of air in the pipes is a slow release the same as when the propane is being burned.
Is it correct to assume the heater worked fine for some period in the past? If so, did anything change in the system before this problem?
Regarding OPD valves and their ability to sense a leak and shut down... If there was air in the piping from the regulator to the heater that should not trigger the shutoff. Not impossible I guess, but it should not happen.
FWIW, we have used propane in 20, 30 and 40 lb cylinders for decades. Since the OPD valves were introduced in '98 I have never had a shutoff trigger other than the time I tried an experiment and connected a loose hose to an OPD valved tank. That is no devices connected, just a new hose. That triggered the shutoff rapidly. As it was supposed to.
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gcrank1
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# Posted: 4 Mar 2024 12:47 - Edited by: gcrank1
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I had trouble with one trying to light one of those high output 'turkey/fish boil' rigs.
Hey Spen, are you holding down the furnace button to get the gas up to the stove safety valve? Most of my stuff calls for x# of seconds then try the igniter. It has taken me several tries and way more seconds to get a few things going after a long shut down or with a long line from tank to device.
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909
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# Posted: 4 Mar 2024 13:10 - Edited by: 909
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I'm always suprised at how long I actually have hold the pilot setting on the knob down in order to make it work. It's always longer than expected. Sometimes for a few minutes ( in order to purge the line of air ) . Once you hear (or see) the pilot actually light, you're supposed to hold it down for an additional 10 seconds or so ( so the pilot stays lit ) before you turn the knob to light the burners.
There should also be an indoor shutoff just below the furnace. Make sure that's in the correct position. The knob should be in line with the gas line running parallel , not perpendicular.
This is a picture of your control Martin control valve. If you call them they'll likely email you instructions on how to adust these settings but hopefully you'll get it to work without having to change the settings set from the factory.
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spencerin
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# Posted: 4 Mar 2024 13:37
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Yep, got all that down. All connections good, valves open, etc.. The heater isn't brand new, but it's been lightly used since installation, always started and ran fine until the time of the original post. Sometimes it did take a little bit of time to start, but it always started. This time it did not.....
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gcrank1
Member
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# Posted: 4 Mar 2024 14:07
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Try holding the pilot button and lightly tapping the control valve with a screwdriver handle; it might just be sticking inside?
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paulz
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# Posted: 4 Mar 2024 14:41 - Edited by: paulz
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I always have about 6 tanks refilled, and still have at least one that will not release gas until I crack the bleeder screw for a bit. Maybe the station is overfilling until it sets off the OPD or it’s just the steep bumpy drive up my hill, or the lp heats up from the cold refillers tank, but it happens every time. YouTube has vids of doing this.
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spencerin
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# Posted: 4 Mar 2024 18:34
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Well, I did lay the tanks on their sides in the truck bed on the way back, and it's a slightly bumpy 300m trip up my driveway. To be fair, I rachet-strapped the tanks, one to each side of the bed, with a couch cushion sandwiched between the tanks and the sides of the bed, on a bed mat. So, firmly secured, with padding to absorb jostling. Is it possible that did something to the mechanisms inside the tanks? Not in a damage sense, but to where I need to "reset" them?
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paulz
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# Posted: 4 Mar 2024 18:48
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Maybe. Seems I read somewhere to only transport upright. To reset the OPD, you just.. I forget, it’s been explained on another thread.
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Fanman
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# Posted: 4 Mar 2024 20:17
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The OPD valve inside the tank is only to prevent overfilling, that's why it's called an "overfill prevention device". It does NOT restrict flow out of the tank. However, OPD tanks have a secondary shutoff that prevents gas flow out of the tank unless it's connected to the gas line or regulator with the appropriate type connector properly tightened... if the same tanks worked before that's likely not the problem.
Some systems also have "excess flow shutoff valves", but that's not in the tank; it's typically used upstream of a corrugated flexible gas line connector. To reset one of those, you have to take the pressure off upstream of the valve (i.e. shut the tank valve and loosen the connection at the tank to vent the gas pressure in the line).
But, most likely you have a bad regulator or switchover valve... they do wear out and fail; in particular, the automatic switchover valves are harder to find nowadays because they frequently fail.
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spencerin
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# Posted: 4 Mar 2024 20:48
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I appreciate the feedback, all. I'll try to "reset" the OPD valves this weekend, see what happens.....
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gcrank1
Member
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# Posted: 4 Mar 2024 21:14
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I don't mind manually switching tanks; certainly eliminates the question of if/what fails.
Doesn't the switchover valve have a manual over-ride?
If it has failed it may be stuck on one side now?
How about disconnect the outlet line from the switcher and blow through each line to make sure the they work? If only one side works run it like a single.
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ICC
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# Posted: 4 Mar 2024 23:12 - Edited by: ICC
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Quoting: paulz Seems I read somewhere to only transport upright.
True. The potential danger is what could happen if the cylinder is over filled and/or if the cylinder is exposed to excessive heat. Cylinders have an overpressure release device built into the valve assembly. Propane expands in volume as it is heated. That safety device is supposed to release pressure if the pressure gets too high. It is designed to release gaseous propane and the cylinder must be upright for that to work. Cylinders designed to be used horizontally (fork lifts) are different.
If a upright design cylinder is transported horizontal there is a good chance the overpressure release will be under the surface of the liquid propane. If pressure is released there are 2 potential dangers. 1. The released liquid propane will instantly freeze skin on contact. 2. As liquid propane turns into a gas it expands 270 times in volume. A few ounces of expelled liquid will fill a large space and could become a large fireball or bomb.
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Brettny
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# Posted: 5 Mar 2024 07:39
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How long you need to hold the pilot button directly can be directly related to how long of a run of propane line is in between the tank and gas valve..if you turn the tanks off.
I have also had regulators or tank valves "lock out" because I opened the valve to quick with no pressure in the rest of the propane line.
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