Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Sporadic Vac Readings

D107 Member Posts: 1,832
I've started my own thread from questions I raised on the 'changing the garber filter' thread.

I was stating that the vac level in our Roth tank goes up as the oil level goes down, reaching as high as 4 at 1/4 tank. We have a 50 micron filter at the tank and a 10 micron spinon at the burner. I know there's debates about this but we've been advised that the 50 micron will catch the heaviest sludge without shutting down the burner which might happen if we only had a 10 micron. This is a Buderus G115-3 with Riello 40F3. Our oil co uses Avalux oil treatment. This is a one-pipe system with a tiger loop. This was all installed in 10-06; shortly after the suction assembly failed and they replaced it with a 3/4" tubing and 'reset the bt depth' whatever that means. From the thread below I'd guess that we'd be better off putting in the hard piping.

<a href="http://www.heatinghelp.com/forum-thread/105059/Roth-tank-issues-2">http://www.heatinghelp.com/forum-thread/105059/Roth-tank-issues-2</a>


  • Kakashi
    Kakashi Member Posts: 88

    If your tank is an outside tank it could be gelling up, this is one hell of a winter for fuel oil. If is a basement tank it's time to find a new mechanic or company.

    If it is an above ground tank check and see if the if the delivery guy turned off the ball valve. One of our guys did it, 20 no heat calls when I was on call. I think I got home at 4 am...
  • D107
    D107 Member Posts: 1,832
    vac readings

    This is an indoor Roth tank. We haven't had any heating problems but some techs on another thread mentioned that the vac readings should not fluctuate with the tank oil levels. The consensus I've gotten over the years is that the hard-piped tank assemblies are better than the rubber suction assemblies. Thanks.
  • icesailor
    icesailor Member Posts: 7,265
    Vacuums & Tigerloops:

    First off, your tank is working normally. Putting the Tigerloop on solved a lot of potential problems. The vacuum readings are developed by the Tigerloop while it does its thing. It also sounds like the fitting on the top of the tank is leaking so the Tigerloop needs to develop suction pressure to overcome the leak. Which is why in the very first Tigerloop install I ever did, I ended up installing a Tigerloop. The burner would run fine during the day connected to the Roth tank but would go out on safety during long off periods at night. It would run fine sucking out of a 5 gallon can overnight but not from the tank. The Roth was on the other side of the wall.

    The photo's I posted are of some Garber Model R filters on a job with a UST that had a lot of sludge. Look carefully at the one photo and look at the sludge at the top (inlet) and look down inside. The bottom of the filter was still clean and passing product. I replaced a lot of underfloor oil lines to sleeved overhead oil lines and into the top of steel tanks. There was a rise in vacuum pressure while the product was sucked up and out of the tank. Once a syphon was achieved, the pressure dropped to zero or as low as the gauge would go. It would only go up as the filter was plugging up.

    It is beyond my comprehension as to what drives this idea that you need some canister for a "sludge pot" to catch the crud when obvious evidence shows that a standard 10 micron spin-on filter works just as well. Working in tandem, the first one does the job as a pre-filter. The second one keeps everything spiffy and tidy. Do you see canister filters packed with rolled up wool socks on over the road diesel trucks? NO. All you see on Diesel powered boats are various forms of Ray-Cor spin on filters. Commercial fishing boats have multiple tandem filter racks because when a set of filters get dirty, it can shut down an engine. You have to be able to switch filter racks without stopping the engine and change filters on the fly. Your live may depend on it.

    My son's father in law owns a trash hauling and excavation business with a lot of equipment. Almost every piece of equipment uses spin on filters. Every filter, when changed, has a date written on it by the mechanic who changes the filter. Techs who keep using wool sock canister filters are killing their industry. I would go three years without service and find the nozzle strainer and pump strainer clean as new with the first filter really bad and the second one very good. The first one like the one in the photo.

    I think that on that first Roth tank, I used a double tapped bushing and put a piece of 3/8" OD tubing into the tank to suck off. But I never had any variable suction pressures with a Tigerloop where the rubber Roth or Shutz tank was working and not collapsed.

    OBTW, where is the second spin-on located? Is it "In" the Tigerloop, meaning is the Tigerloop running through it? Or is the Tigerloop sucking out of the filter?

    One way can filter the oil at a 20 to 1 ratio, the other filters the oil as it is needed. It depends on where you install the filter.

    Also, after your burner has been off for a few hours or overnight, start the burner (especially if the tank is low on product) and watch through the clear plastic top of the Tigerloop. If you see foaming, the suction line had lost prime and you had a vacuum leak. The burner will run on the oil in the Tigerloop until it can prime itself. That's what makes Tigerloops so good. Another reason that in some European Jurisdictions, they are required on ALL installs.

    Sorry for being so long. It's in my nature.
  • D107
    D107 Member Posts: 1,832

    Thanks for your reply, always appreciate the detail. Next time I'm out to the house I'll watch the cycle a bit and look for the tiger loop foaming--which i've seen before, and vac reading. When burner is not running, vac reading is always less. I'm attaching photos, but Tigerloop was installed as per Tigerloop instructions. FYI I always have a hard time getting the oil co techs to bleed the line for the annual tuneup, either after or before replacing the filters. Most advice I've seen from good techs says they bleed it just as a precaution to remove any sludge from the line. A really good private tech I use occasionally to check things out told me while the Tiger loop is in correct order, there was alot of wasted linework done. For one thing it would be better to have the tigerloop installed right over the spinon. Tigerloops are instructed to be replaced every 8 years, so we have another year to go. And since the bio-fuel percentage is going up to 20%? we'll probably have to use the new biofuel tigerloop model.

    Note re: tank photo, we have since made both fill and vent two inch lines.

    As for the 50 micron we don't use wool filters, never have. they use those white foam elements, and whenever we replace them there's never sludge in them. The spinons we've gone two years without replacing and never seen sludge in them either.

    I'm curious that if we did replace the suction assembly with the hard pipe double bushing etc, would that stop the vacuum leak coming from the top of the tank or is it unrelated?
  • icesailor
    icesailor Member Posts: 7,265
    Nice neat install.

    Nice neat install.

    I mentioned a 20-1 filter rate. That one is it. If the Tigerloop is closest to the burner and the filter is connecter to the inlet of the tigerloop, it only filters the oil that it needs in the moment. Like if you are using a 1.00 GPH nozzle, the filter only filters 1.00 GPH of oil. The way it is connected now, the filter is filtering whatever the fuel pump is pumping to do its two pipe operation. That is a good way to pipe a burner with an outside oil tank that delivers cold oil. The resistance of the 20 +/- GPH oil, going through the pump and Tigerloop will warm it up for a better burn. IMO.

    I personally, don't like those canister filters. There are too many places for them to leak. I don't know who makes it but it looks like  General. I always had problems with the small red gasket on the top bleed screw. And there's no place to add a gauge.

    IMO, you will find that the Garber gauge, located where it is, is the best place for it. It will show you the restriction in both filters. Just not which one. If the gauge suction pressure goes up though, it will probably be because the first filter (at the tank) passed sludge and it was trapped at the Spin-On at the burner because of the smaller Micron filter.

    Putting the filter at the inlet of the Tigerloop, protects the Tigerloop. IMO.

    But, nice neat install.  
  • D107
    D107 Member Posts: 1,832
    one-pipe, not two.

    Ice Sailor, as far as I understand and have been told, this is a one-pipe system, not two. tiger loop was put in after install by service division who were not as good as the original installers, therefore there is some extra oil piping there that could be neatened up.
  • icesailor
    icesailor Member Posts: 7,265
    edited March 2014
    One Pipe/Two Pipe:

    It IS a one pipe system.

    Under the rules of pumps and physics, a Roth type tank where you draw off the top with a tube inside that runs to just off the bottom of the tank and runs to a burner pump develops enough suction pressure to get the product out of the tank and work on a syphon to deliver product to the fuel pump. The weak link in the chain is the fitting on the top of the tank that acts as a shut-off and connection to the oil line. The Tigerloop eliminates any problems you might have with the possible suction leak. Before the installation of the Tigerloop, after a long shut down, when the burner would start, it would run for a while and run off the fuel in the line from the tank. When the air gets to the fuel pump, it stops until it can bleed off the air. It will stop. The Tigerloop keeps it going and vents the air.

    Everyone sees a project differently. It would be interesting to see what the original installer would have done to install the Tigerloop. The filter was installed in the present location by the original installer. The Tigerloop, installed afterwards. Many would have installed the Tigerloop where the filter is located to use the flex connectors. Ridgid Lever Benders are a beautiful thing in the hands of a creative installer.

    For anyone that doesn't know it or cares, a 1/2" OD lever bender is a wonderful thing if you want to bend 3/8" od protected tubing. A perfect bend every time.
  • billtwocase
    billtwocase Member Posts: 2,385
    looks like

    installer actually either read instructions, or attended classes by Roth. Technically one is supposed to be Roth certified to instal their products. Seeing a lot of installs out there, many are not. I personally do not instal, or like the filter where it is. One is potential air leaks, two is trying to replace it and working all the surrounding fittings loose while doing so. Instal it at the burner with black iron fittings
  • D107
    D107 Member Posts: 1,832
    filter location

    Thanks. I have seen many threads on various heating sites on this and it is always a debated topic. As I recall some techs say the benefit of the filter being at the tank is that is more likely to keep the lines clean between the tank and burner. (Some techs use a third filter cannister--just a pot without a filter--at the tank before the 50 micron to catch the coarsest sludge.) I'm not looking to re-start that debate all over again, just sayin'.

    Since we're supposed to replace the tiger loop next year--based on tiger loop's claimed eight-year life expectancy--perhaps we'll revisit this. At the time the boiler was installed I don't think the combination tiger loop/filter assembly was out yet. Of course now with the bio-fuel percentage going up to 20%? we'll have to get the special tiger loop for that.
  • icesailor
    icesailor Member Posts: 7,265
    Replacing Tigerloops:

    IMO, don't replace with the combo units. Why pay for a filter you already have?

    As far as those empty filter canisters to catch sludge, that's become a Urban Legend among some oil burner techs, perpetrated by the same ones that think that Tigerloops suck. Tell that to the Europeans where in some jurisdictions, every install has to have one.

    Look at the photo's I posted. There was so much sludge crap in the 2,000 gal UST with no filers in the primary oil pumps that the pumps would die when the 2 stage oil pump strainers plugged up after 30 days. I made a filter rack to have two spin-on's on each side so someone could change filters by switching to the other side and not stop 5 burners. Notice the sludge on the top of the filters. That's the inlet. Plugged up. Look in the bottom, it's clear. The vacuum was going from 1.5" to 3" and still passing clean oil. Those extra canister filters are just another potential source of an oil or vacuum leak.

    When you pump suction water wells, you use the absolute minimum amount of fittings to cut down on potential sources of vacuum leaks. Why would you do it any differently? They outlawed compression fittings on oil because of oil weeps and vacuum leaks. The more you tighten a compression fitting, the more it leaks.

  • D107
    D107 Member Posts: 1,832
    edited March 2014
    Suction Assembly and B20 Bio

    Last time at the house I checked the tiger loop during burner operation and there was no foaming, at least then.

    So back to original problem of 4.5 vac readings, at annual tuneup I'd like the techs to at least open the Roth suction assembly and look at the opening at bottom of the house. Shortly after installation six years ago, they had to replace half-inch rubber hose with 3/4" hose––not sure if wider is better for this item. Roth recommends 3/8" fuel feed. I think spec is 3 inches off bottom, but some companies have kept them six inches off ground. If it looks closed up I'll ask them to replace with metal pipe. I have to mention also that this problem has first appeared as the oil company has gone from B5 to B15 and B20 in one year. So not only does the btus per gallon decrease with Bio, it may cause other issues, not yet known.

    Paraphrased from Roth:

    The problem of the suction foot slipping off has been resolved with the addition of a hose clamp;

    the problem with tubing collapsing under vacuum has been traced to the

    aforementioned fuel additives, which can also cause seal failures on air

    shutter pistons due to adverse affects on rubber products. Additives containing

    napththa should not be used. As an option, suction assembly may be replaced

    with a ‘hard-piped’ copper suction line and duplex bushing as in standard steel

    tank installation. In that scenario, the fuel additives do not appear to be a

    concern. The manual also says that additives added by the distributor in bulk

    before loading into the delivery truck do not seem to be a problem.

    I finally found the quote--I think from Nora--which explains lift and vac readings:

    "1” for each 1

    ft of lift, 1” for each 10ft of run and 1” for filter."

    So are the techs here saying that the higher vac readings would only happen for a brief interval before a siphon is established when burner is sucking oil?

    Otherwise, based on that formula at half tank we’d have about 1ft of lift, a 10ft run, and 2” vac for two filters = 4” vac reading.  A full oil tank would reduce lift a bit. Vac reading always rises during operation, then goes down.

  • icesailor
    icesailor Member Posts: 7,265
    Vacuum readings:

    If the static suction pressure is say 2" Hg then that is the static suction pressure at rest. If the pump starts and the pressure rises to say 5" Hg, but will go back to 2: Hg when the pump stops, that difference is resistance through the piping and fittings.

    Whenever I had a problem with a Roth type tank with the rubber pick up, I replaced it with a piece of copper tube.
  • Techman
    Techman Member Posts: 2,144
    Vac readings

    Full tank , low vac reading :higher vac as tank oil level drops. The weight(height) of the oil in the tank does not affect the vac reading?
  • icesailor
    icesailor Member Posts: 7,265

    That's right. If the pump isn't pumping, and the "syphon" is established, the only pressure on the gauge is pressure. It will correspond with the level in the tank. At the very top of the syphon tube, the pressure will be negative inside the pipe. Just like a closes circuit heating zone.  When the pump starts, if it shows negative pressure Vacuum), it is showing the vacuum restriction to overcome the resistance of the piping. If the oil piping was 2" pipe, there would probably be no vacuum because of a lack of restriction.

    The non pumping is the static pressure, whether pressure or vacuum. The pressure "pressure or vacuum) when the pump is pumping is the working pressure.

    If there is absolutely no vacuum resistance on a pump and you set it to deliver the highest pressure and volume it can, and you cause the suction/vacuum pressure to go up. the discharge pressure and volume will go down.
  • D107
    D107 Member Posts: 1,832

    "If the pump isn't pumping, and the "syphon" is

    established, the only pressure on the gauge is (static?) pressure. It will

    correspond with the level in the tank."

    So --you meant static pressure in that sentence right?--it is not affected by weight of the oil but the oil level.
  • icesailor
    icesailor Member Posts: 7,265
    Another way:

    Let me put it another way.

    If you have a 4" pipe that rises from the floor, 100' in the air and it is filled to 50' with water, and there is a gauge placed at the bottom of the column, the gauge will read 23.7# PSIG. If, at 5' above the ground, you connected the top of a tank with the 4" pipe and lowered the water to the 5' level, so that the level in the pipe and tank are equal, gauges at the bottom of the tank will both read 2.17# PSIG. If the crossover pipe between the 4" pipe and the tank had a valve on it and was shut off, and you  drew off the tank, the 4" pipe gauge would read 2.17#. Same as the one at the bottom of the tank. If you connected the tank to a oil burner pump with a 1" pipe so as to eliminate restriction, and installed a valve at the pump, they would both read 2.17#. If you start the pump, because of the 1" oversized pipe and lack of restriction, the both (all) gauges will read 2.17#. If you close the valve completely, the gauge at the tank will read 2.17# but the one at the pump will start to show more vacuum pressure. For clarity, I should have said that all these gauges should have been compound pressure/vacuum gauges 30" Vac-0-30#+ pressure. The gauge at the pump can climb to 30" Vac if the pump can accomplish that. But the gauge at the tank will still read 2.17#. If you slowly open the valve between the tank and the pump, the pressure will rise to 2.17#. All gauges will read 2.17 until the tank empties.

    If you have a well water pump and have a gauge on the suction side and well side of the pump, the gauge is marked off in feet, and it is 10' to water from the level of the water to the bottom of the gauge and the pump isn't primed, the gauge will read zero. If you prime the pump and have water flowing, and shut off the pump, the gauge will read 10'. Static Pressure or static lift. If the pump starts and starts pumping water and the gauge now reads 15', that is equal to 5' of restrictive lift. Pumping lift.  If you look on a pump chart and look under the 10' lift table for the GPM/GPH rate, it would be wrong because the suction lift is actually 15'. The pump delivers less water at a 15' lift than a 10' lift because the pump uses more energy lifting the water from 15' than 10' which is actually restriction.

    With a Tigerloop, although some don't agree with my terminology, it is a "Pump" and in fact, two pumps. One part uses the oil pump on the burner to circulate oil through the tigerloop which creates a suction through the tigerloop. It is actually a closed loop like a closed loop zone in a heating system. The suction created by the restriction inside the Tigerloop causes higher suction pressures that the oil pump can create alone as a single pipe. Before Tigerloops, some oil guys used what they called a "Cheater Loop" which was just a Tigerloop, done with fittings without the ability to get rid of the air.

    Incidentally, it is atmospheric pressure pushing DOWN on the oil tank that is actually what gets the oil to the pump. The vacuum created must be filled.

    Gas (Nat. Gas or compressed air) under pressure is trying to equalize itself and flows out the pipe.

    I hope that explains what you asked. If some of my terminology is wrong, its because I don't have all the information I had before I moved. At 70 years old, my terminology gets a little fuzzy.
  • D107
    D107 Member Posts: 1,832

    Appreciate your answer.
  • icesailor
    icesailor Member Posts: 7,265
    edited March 2014

    Also, in the above example, you mention weight.

    The 4" pipe filled with water, holds 32.64 gallons of water in the pipe which weighs 271.89 #. But the pressure gauge at the base of the stack will be 21.7#. The amount of water in the pipe only effects the gauge by how high it is in the pipe above the gauge. The weight of the water in the pipe will increase in weight by the size of the pipe. If you doubled the diameter of the pipe to 8", it would hold 130.56 gallons of water and would weigh 1087.56#. The gauge would still read 21.7#. If you tied both pipes together, the gauge would still read 21.7#.

    Oil weighs less than water. My example is only for water.

    Plumber's Math. Don't leave home without it.
  • drhvac
    drhvac Member Posts: 190

    icesailor, where are the pictures you are talking about?
  • icesailor
    icesailor Member Posts: 7,265

    I'm not sure what pictures you are asking about. I looked through my recent posts on this topic and didn't wee that I had meant to add some.

    Refresh my aged memory. I'll post them if I still have them. I lost hundreds of them when someone borrowed my camera at Lowes, thinking it was a wallet and didn't return it.
  • drhvac
    drhvac Member Posts: 190

    Below is a quote from your first comment on this thread.

    The photo's I posted are of some Garber Model R filters on a job with a UST that had a lot of sludge. Look carefully at the one photo and look at the sludge at the top (inlet) and look down inside. The bottom of the filter was still clean and passing product. I replaced a lot of underfloor oil lines to sleeved overhead oil lines and into the top of steel tanks.
  • Kakashi
    Kakashi Member Posts: 88
    flex line

    A flex line between the tiger loop and filter and they used copper lines going to the pump...

    My company has been putting in Roth tanks for awhile now and we have noticed that the rubber SUCKtion line starts to get very soft and often collapses on itself.

    We have been using copper lines instead of the rubber ones for obvious reasons.
  • icesailor
    icesailor Member Posts: 7,265
    Flex Lines:

    I seem to remember that part of the Listing for flexable lines is that they must be replaced regularly. Two years come to mind. There was a huge kerfuffle when they first came out. This was the code requirement as I remember, They had to be replaced on a regular basis. As part of regular service.

    How do you hard pipe with Copper, a two pipe or Tigerloop'ed Riello?

    Not easily?

    Weren't Flex Lines a solution to the introduction to swing out doors on oil burners to take away any excuse for lazy service people who didn't want to be bothered cleaning out the Kibble & Bits from the bottom of the chamber and causing premature failures of boilers?

    Why did they develop "Soot Saws"? Because cold start boilers fill up with crud. Where does it go? To the bottom of the boiler. How do up get it out? Remove the burner or open the front. What happens if it only has a copper oil line? Oil all over, stinky house and smelly clothes. "I'll get that next time" or "I'll leave it for the next guy".
  • icesailor
    icesailor Member Posts: 7,265


    Sorry if I didn't understand what you were asking. If it was photos of dirty Garber filters, you can find them here. Just look down the string. Hope this is what you were after or asking.

  • Kakashi
    Kakashi Member Posts: 88

    Our company does it every 2 to 4 years for an outside or underground tank due to the "extra" additives in fuel oil. on a basement storage tank its up to the service tech...

    If it's up to me, I look who was there before me. Some people clean up with brake cleaner after they do the strainer and that is a no-brainer to me. I then add an inch or 2 inch nipple with a coupling so when someone else changes the strainer it doesn't touch the rubber hose.

    As for the rubber Roth suction line...I have one on my van for my night service. If its during the day and is a friendly basement and my Manager gives me time.
  • icesailor
    icesailor Member Posts: 7,265
    Brake Cleaner:

    Ever try PVC cleaner? Its cheaper and more readily available. Will brake cleaner get Rectorseal #5 off your tools and fittings?