Propane Quality
I'm curious if there are variations in the quality of propane from different suppliers.
After 16 yrs my high efficiency boiler became intermittent during the ignition cycle. The blower, ignitor, gas pressure, flu, recirc pumps and controls all have been checked and working normally. You can hear the gas valve and ignitor start but no ignition most of the time. When it does ignite the woosh is clearly audible.
I finally replaced the boiler with an identical one (new) and the same problem occurs. Both of my propane tanks were filled this fall. That is when this problem began. The supplier suggested it's because the boiler is high eff and I should go to 85%. After 16 yrs with no problem I find this an unacceptable alternative.
Comments
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has anyone checked your gas pressure at the boiler when it is trying to fire?
If regulators are 16 years old, I would suspect them.
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Was a combustion analysis done? If so, what are the numbers?
Bob Boan
You can choose to do what you want, but you cannot choose the consequences.
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I checked the static pressure on the boiler gas valve. It was about 10" and about 9" when running on high fire. Boiler specs say 5-13" with max of 1" pressure drop on high fire.
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I'm still waiting on a service call to chk combustion gases. I have been reluctant to buy a meter but it's a pain trying to find a tech with the right equip in this area. I have made slight adjustments to the gas flow on the valve but they seem to have no effect.
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Propane quality can vary from supplier to supplier, not so much in terms of the fuel gas itself (although if by "propane" you actually mean "liquid petroleum gas" that can very, too) but in terms of how much moisture there is and other non-combustible components.
You mention "Both of my propane tanks were filled this fall. That is when this problem began." The first rule of troubleshooting is what, if anything, changed just before the problem began.
And there you are.
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England1 -
That valve is extremely sensitive to any adjustments and that shouldn’t be done without a combustion analyzer and the proper knowledge of how to use it.
Bob Boan
You can choose to do what you want, but you cannot choose the consequences.0 -
there’s training required just buying the tool is not enough.
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I agree that’s an unacceptable answer; in fact it’s just plain B.S.
Did you switch LP suppliers or have new tanks put in?
Bob Boan
You can choose to do what you want, but you cannot choose the consequences.0 -
It's impractical to replace two 500 gal tanks. I plan to rent a 100 lb tank tomorrow from a different supplier and see what happens.
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I’m not suggesting that you replace the tanks. I was asking if they had been replaced or if you changed suppliers.
Bob Boan
You can choose to do what you want, but you cannot choose the consequences.2 -
Sometimes (though rare) you can have moisture in the propane. The propane is supposed to have something added to this. (like Drygas is added to a car). If moisture is present, it can cause issues which are usually intermittent. It can cause regulators to freeze because the propane act as a refrigerant.
Also check all regulators to make sure the vents are clear. Sometimes bugs and wasps can plug a vent.
The supplier's statement that the boiler is the problem because it is high efficiency is just stupid.
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Methanol should be added to the tanks if moisture is present or suspected.
Again, is this a new LP supplier or the same one that you’ve had?
Bob Boan
You can choose to do what you want, but you cannot choose the consequences.0 -
The same one I've used for several years. I've always trusted them but I didn't agree that I should be using an 85% boiler. There are likely millions of high eff boilers in use without these problems.
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Update:
This weekend I made an incredible find. There is a small HVAC shop just 4 miles down the road. They install and service Triangle Tube boilers.
They don't have a sign. No label on their trucks and no advertising. No need to do so because they are always booked. Google search for HVAC or boilers does not bring up their name. Word of mouth advertising.
I called late Sat and they were here Mon morning. The tech was trained, certified and proficient. Went right to work with the analyzer. Switched between hi/lo fire a dozen times while making adjustments to fine tune the numbers. When he was finished the boiler ran perfectly. Took about 45 min.
He confirmed that in this area he has had to re-adjust several hi-eff boilers after a propane fill. Apparently Triangle Tube and perhaps others are very sensitive to slight differences in propane which he says doesn't seem to happen in other parts of the country.
I'm so happy I nearly peed my pants.
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😊😊😊😊fingers crossed. Just have to find the right guy. Nowadays it is easier said than done it's like looking for a needle in a haystack
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Take real good care of that one!
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I went through a period of about a year where any high efficient boiler on a certain companies LP tank would give failed ignition codes, no amount of combustion adjustment would get it working. This was in Michigan, LP company never offered any compensation, I lost a couple of customers over it because nobody believed me it was the fuel supply.
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Not surprising. It's worth remembering that LP gas is not a single gas. It is a mixture of propane and butane, sometimes with a trace of methane and often some methanol. Exactly what mixture you get should — but doesn't always — vary with expected outdoor temperature, so that the vapour pressure is reasonably constant.
Br. Jamie, osb
Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England3 -
Commercial propane is a witch's brew of whatever's left on the shelf that refinery wants to dump into it. You can get all sorts of heavier hydrocarbon species. However, HD-5 is 95% pure propane with less than 5% ethane. It's like high test gasoline. It is the most consistent, predictable blend. You can switch it it (and pay more) or try to work with what you have. Just know that regardless of what you fill it with now, all the heavier alkanes that have been introduced into that cylinder or container will remain there until Geraldo finds them. Should the tank level get below 20% you run the risk of suddenly burning crap that has a much higher BTU analysis. The only way to know what's in there would be to analyze a sample using gas chromatography. That separates and identifies the species. I used to joke about propane retailers like Cheech & Chong: "Hey maan, choo wanna' do some good stuff? I got this Venezuelan blend, man its reeel smooth,…" Ok, I'll behave.
Your tank's ability to deliver vapor state fuel is called the 'vaporization rate'. It is determined by temperature and the 'wetted surface' of the tank. This means at a given temperature, a full tank has the ability to flash more liquid into vapor than the same tank at the same temperature but 20% full. Also, if you calculate the square inches that are wet on a vertical D.O.T. cylinder vs. the same size ASME container you'll see the horizontal container does better. Burying containers actually keeps them warmer than one exposed to the cold wind above ground.
The whole delivery system must be properly sized. You'll want the Medium Pressure regulator as reasonably close to the appliance as practical. This minimizes the low pressure side's pressure drop, which is significant for the skinny tubing allowed per the charts in the codes. I've never seen an appliance that can read a code book so they're going to be like my beagles and do what they want to. If everything seems sized correctly but it sometimes takes a dump at high flow conditions have your LP provider conduct a Lockup Pressure test on the regulator. If it's old, it may need replacement. Some companies might replace an orifice and adjust the set spring by why not replace for that they cost?
The stated inlet pressure on an appliance valve is the pressure read off any provided test port on the inlet with the house under full load and the appliance firing. If no such port is provided, then it would need to be read immediately upstream of the valve's inlet boss. This, however, does not take into account foreign matter clogging the inlet boss screens, such as copper sulphide "black flakes".
Back when I was a Regional Quality Assurance Manager for a major fireplace mfr. I obtained a 30lb. cylinder of HD-5 that my mfr's lab had analyzed with GC as pure. I would substitute this for the client's fuel then assess and adjust guided by combustion analysis. Save my bacon a number of times. Just know that sometimes you ASSume things that come back to bite you. I was way up in the Pocono Mtns. off a gravel road where the customer was videotaping me without my consent. When I read fluctuating inlet pressures I disconnected the LP tubing at the appliance and opened the gas cock with my hand in front of it. Gravel shot out bouncing off my hand! Another time, I found CSST lines full of water on a new construction gig where they roughed in the lines without protecting the ends and it rained. Just walk it step by step confirming what you have and when you lose it or it falls out of spec.HTH
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