Foam in Tiger loop

Reply

  #1  
Old 02-19-15, 09:56 AM
Member
Thread Starter
Join Date: Feb 2015
Location: USA
Posts: 12
Foam in Tiger loop

I have an Armstrong furnace with Beckett burner and a Type T601 Tiger Loop. My tank is underground and the supply line runs under my garage to the rest of the basement. After the furnace runs for a while, the fuel in the tiger loop starts to get frothy, and then the burn starts to cut in and out. I have two technicians visit. The first replaced the filter and nozzle and blew out the supply line below the filter. That seemed to help some but didn't resolve the problem. Two days later (Feb 18) the second tech blew out the line again -- this time below the tiger loop and above the filter -- and opened the Firomatic Valve some. Again, that helped for a while but today it is acting up again. Neither tech detected any leaks, but the second suspected it could be caused by trash in the tiger loop, which I understand cannot be serviced. The HVAC company wants nearly $600 to install a new tiger loop, which seems exorbitant.

So, I have two questions: 1) does this sound like a problem from a faulty tiger loop (the unit has been in service since Oct 95!), and 2) is it possible for a novice to replace the tiger loop.

Thanks in advance for your suggestions.
 
Sponsored Links
  #2  
Old 02-19-15, 11:53 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 50,674
Likes Received: 115
Welcome to the forums.

I'm not an "fuel oil" pro. They'll stop by.

I was just looking at some troubleshooting information.

Name:  tiger.jpg
Views: 1569
Size:  35.5 KB

mitcomfg images Us1.pdf
 
  #3  
Old 02-19-15, 02:27 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 13,926
Pete gave you a good list of possible causes. I'll follow up with some questions:

Has anyone checked the vacuum? That will tell you quickly if the lines might be the problem. Anything over 5-8" of vacuum indicates a restriction of some sort.

How much fuel is in the tank? Usually you can use a piece of pipe, or better yet, a piece of wood down through the fill or vent to measure if there are not elbows in the pipes.

The Tigerloop can be cleaned with kerosene (do not use any kind of solvent) but I seriously doubt that is the problem.
Changing a Tigerloop is easy if it comes to that.
 
  #4  
Old 02-20-15, 05:11 PM
Member
Thread Starter
Join Date: Feb 2015
Location: USA
Posts: 12
Grady & PJmax -
Thanks for your replies. In answer to your questions, no one has checked the vacuum. As to fuel, there is about 14" in the 550 gal tank.
That addresses point 3 in Pete's list from the Tiger Loop info. As to 4 and 5, I can't them being issues since the unit has operated okay on this furnace since Aug 98. Number 2 also can be ruled out since it is an intermittent problem, and it never really stops, just stutters. I will try to describe it better since I have observed it quite a bit since my first post. As to a suction leak, if that would also allow fuel leakage there are not signs, unless it could be in the line under the garage floor.
On start up, the burner will light, hesitate a second, then relight. After running a minute or two --
usually about the time the circulation fan comes on -- very small bubbles begin to form in the tiger loop. As they increase, the oil level drops and the burn begins to get interrupted and the damper in the flue will flap. A few large bubbles then appear above the outlet from the tiger loop to the burner, after which the foam begins to subside and the unit then runs okay for the rest of the cycle.
Another mystery is that when the filter was changed there was water in it, but no water was found when the tank was checked. This also was the case when the furnace was serviced last August, and the techs were unable to provide an explanation for it.
A new question: How should the Firomatic Valve be set, i.e. should it be open as far as possible or partially closed? I have experimented with various settings the past two days, but it doesn't seem to make much difference.
Thanks again for your replies.
 

Last edited by Grady; 02-20-15 at 06:46 PM. Reason: Changed "fuel" to "flue" for clarity
  #5  
Old 02-20-15, 07:08 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 13,926
A suction leak may or may not leak oil. Often not.

From your description of the operation, I'm betting on a suction leak. First thing I'd do is check all flares & fittings (especially at the filter). It might be worth the cost just to replace the whole filter.
Firomatic valves are also notorious for vacuum leaks. BTW: Valve should be fully open.


Water in the fuel filter is not a good sign. It is quite common to find water in a filter but not be able to detect it in the tank. Too many reasons it isn't detected to get into here.
 
  #6  
Old 02-21-15, 09:36 AM
Member
Thread Starter
Join Date: Feb 2015
Location: USA
Posts: 12
Grady -
Your follow-up much appreciated. I have checked all the connections and they are tight. Is there some other way to check, like using soap bubbles when checking for gas leaks? I also completely opened the Firomatic valve. That seemed to help with the intensity of the interruptions to the burn and reduce the fumes of unburnt fuel, but the problem persists. The confusing thing to me is that if it is a vacuum leak, why would it be intermittent? I am attaching a video of the cycle it goes through, and you will see at the end it settles down and behaves normally.
https://dl.dropboxusercontent.com/u/62942189/MVI_3441.AVI Would be very interested in what you think after watching.

Addendum: I timed a cycle to place the video in context:
1 minute after burn begins, foam begins to increase slightly
1 1/2 minute into cycle circulation fan comes on
1 min 40 sec bigger bubble appears
2 min 40 secs foam increases, oil level drops, burn begins to stutter and flue damper flaps
3 min foam dies down and burn evens out
5 min 50 sec burn ends
8 min 40 sec circulation fan stops
 

Last edited by ouddingen; 02-21-15 at 11:27 AM. Reason: add information
  #7  
Old 02-21-15, 11:34 AM
PJmax's Avatar
Group Moderator
Join Date: Oct 2012
Location: Northern NJ - USA
Posts: 50,674
Likes Received: 115
At the end of that video.... the glass is full or empty ? It looks empty.
 
  #8  
Old 02-21-15, 11:50 AM
Member
Thread Starter
Join Date: Feb 2015
Location: USA
Posts: 12
There is about 3/4" of fuel in the glass at the end of the video. You will see the level start to build back up about 50 seconds into the video. That is about where it stays when the the furnace is stopped, and when it is running like it should.
 
  #9  
Old 02-21-15, 02:19 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 13,926
Sorry, I couldn't access the video. For some reason my system doesn't like dropbox.

I am absolutely convinced there is a vacuum leak somewhere. Oil is draining from the line back into the tank.

Take all of the fittings apart & examine the flares. They should be smooth on the inside with no scratches or the top being rolled into the flare. Also check the fittings themselves to be sure there is no nick or scratch on the fitting face.
 
  #10  
Old 02-21-15, 02:41 PM
Member
Thread Starter
Join Date: Feb 2015
Location: USA
Posts: 12
Try this link on OneDrive:
https://onedrive.live.com/redir?resid=CA0313088D066EFF%21529 I am still baffled by why a leak would only affect operation about 1/3 of the time and at about the same time in the burn cycle.
 
  #11  
Old 02-21-15, 02:54 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 13,926
Good video. Thanks. Does the amout foaming relate at all to how long the burner has been off? Try it after being off for 5 minutes then turn the furnace off for a couple of hours & try again. I'd be kind of surprised if there isn't a good bit more foaming or bubbling after the longer off cycle.

To eliminate the Firomatic, you could install a flare union for testing purposes.
 
  #12  
Old 02-21-15, 03:10 PM
Member
Thread Starter
Join Date: Feb 2015
Location: USA
Posts: 12
Given the weather we are having right now in Northern VA, I am reluctant to mess with anything too much since the furnace is still operating after a fashion. If we still have power in the morning, I will crank up the woodstove and see how it goes after being off for a while. Right now I want to conserve the dry wood I have inside in case we have a power outage overnight. However, we did use the woodstove a few days ago and the furnace didn't run for several hours and I don't think it acted much different on startup, but I wasn't watching it as closely then.
As for bypassing the Firomatic, I don't have a flare union or any way to get to a hardware store in this weather.
Thanks for your input, and I will let you know what I discover tomorrow.
 
  #13  
Old 02-21-15, 03:17 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 13,926
Gotcha. I take it you are getting the snow/sleet/freezing rain. At this point we've gone to light sleet & it's 30* so it's going to freeze on everything. We got about 1-1.5" of snow before the sleet. Forecast says rain later.
 
  #14  
Old 02-21-15, 03:44 PM
Member
Join Date: Nov 2012
Location: USA
Posts: 3,698
Likes Received: 4
I am posting this link that might help you understand how a Tiger loop works, I had know idea what it was and thought it was interesting.
http://www.westwoodproducts.com/imag...ability_us.pdf
Geo
 

Last edited by Geochurchi; 02-21-15 at 04:34 PM.
  #15  
Old 02-21-15, 03:57 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 13,926
Geo, your link didn't show up.
 
  #16  
Old 02-21-15, 04:36 PM
Member
Join Date: Nov 2012
Location: USA
Posts: 3,698
Likes Received: 4
Thanks that's because I didn't add it.
Geo
 
  #17  
Old 02-21-15, 06:46 PM
Member
Thread Starter
Join Date: Feb 2015
Location: USA
Posts: 12
I read this a few days ago before my first post. It does a good job of explaining what a tiger loop does, but almost nothing about how it does it. I have not been able to find much of anything about the inner workings of this unserviceable device.
 
  #18  
Old 02-21-15, 07:43 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 13,926
On the top of the Tigerloop is an air vent & inside is a float. The vent remains open unless the level of the oil in the chamber raises the float which then blocks the vent.
The foam is air in the fuel. Some of that air is vented with each recirculation of the oil between the Tigerloop & the pump.
A typical fuel pump with the by-pass plug installed will move about 17 gallons per hour. With a Tigerloop, you only pull from the tank the amount you are burning the rest of the 17 gph is recirculated in the loop & after a few passes completely de-aerated.
You are pulling air from somewhere as evidenced by the bubbles, particularly the large ones.
 
  #19  
Old 02-22-15, 01:11 PM
Member
Thread Starter
Join Date: Feb 2015
Location: USA
Posts: 12
Grady -
With temp in the 40s today I was able to run your test without firing up the woodstove. You were correct that there were more foam and bubbles after 2 hours off, and a bit more sputtering before it finally settled down. The sputtering always occurs when the oil level in the tiger loop drops lowest, and I still don't understand what determines the level. The Westwood FAQ states that anywhere from nearly empty to full is normal.
In trying to figure this out I came upon a couple of recommendations to use flexible pipe between the tiger loop and the burner. Would it be worthwhile to change from the copper line when I take the fittings apart to check them? And what is the best way to empty the line as much as possible before taking it apart? I assume it would be to close it before the filter and let it run until it runs out.
I also was wondering if there is an oil safety valve less prone to leaks than the Firomatic. And you suggested it might be worthwhile to consider replacing the filter. My current filter is a Model 1A-25A from General Filters Inc in Novi, MI. It has probably been there since the house was built in 1979. What would you suggest as a replacement?
Finally, I assume I will need to find an HVAC supply shop to get these things rather than Lowe's or Home Depot.
Thanks again for your help (and patience).
 
  #20  
Old 02-22-15, 02:27 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 13,926
Thank you for working with me & testing my theory.
Something just came to mind: Did this problem start shortly after the latest filter change or other disturbance to the fuel system?
If you are going to change the filter & want to stay with the same style as opposed to a spin-on (like a car oil filter), I see nothing wrong with the 1A-25A or anything similar with a cast iron top. I don't know why but I have not had good luck with the aluminum top filters. An actual hardware store (Ace, True Value, etc.) will likely have the filter. Replace the fittings too. Use #2 Permatex on the pipe threads of the fittings.
As far as I know, Firomatic is the only game in town for that type of valve.
 
  #21  
Old 02-22-15, 07:52 PM
Member
Thread Starter
Join Date: Feb 2015
Location: USA
Posts: 12
Grady -
There was not a filter change or other change to the fuel system before the onset of the problem. I had the furnace serviced last August, and the tank filled a day or two later. Then a couple of weeks ago my wife began to say she smelled fumes in stairwell and heard the furnace make funny noises. That led to the service calls I mentioned in my first post.
One thing that had changed was the weather. My basement garage -- which the supply line runs under -- is unheated, and I noticed from my car's external thermometer it had gradually been getting colder and colder. The last two days I have opened up the door to the basement and placed a fan near the door to get a little heat in there, and that seems to lessen the problem a bit, presumably because the fuel is slightly less cold.
Do you have a view on flexible vs rigid lines to connect the tiger loop?
Thanks again.
 
  #22  
Old 02-22-15, 09:17 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 13,926
I was hoping the problem started right after the fuel system had been disturbed. That would be a good indication of an air leak at the filter. So much for that idea.

Flex lines are really nice when it comes to service but they are supposed to be replaced every 5(?) years. I have seen them in service for close to 10 years.

What kind of temps are you seeing? I've been down to 1* with no problems with an above ground tank. Now you have me thinking maybe an oil viscosity problem but the fact you see bubbles so quickly...
 
  #23  
Old 02-23-15, 05:22 PM
Member
Thread Starter
Join Date: Feb 2015
Location: USA
Posts: 12
Our temps probably have not been all that different from yours, perhaps a bit milder. However, after the second night with the garage door open I saw further improvement today. The foaming began later in the cycle, there were fewer large bubbles, the foaming did not reach as high, the oil level did not drop as much, and most importantly there were no disruptions to the burn.
Your mention of viscosity reminded me that when the tank was filled in Aug the driver said that it was industrial/commericial grade, which he intimated was a better quality fuel. However, maybe it is not the best thing for my type of furnace.
I also wondered about all the CO2 used to blow out the supply line -- a total of 4 cartridges in the 2 visits 2 days apart. Could that feasibly be part of the problem?
 
  #24  
Old 02-23-15, 06:06 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 13,926
The CO[SUB]2[/SUB] certainly should not cause any problems. If your burner guy has a push/pull pump, he could easily pump fuel treatment such as SBG or Technol 246 backward thru the lines to help clean them. They could very well be partially clogged with sludge. The blowing with CO[SUB]2[/SUB] can help clear a severe clog but it does little to actually clean the lines. I've seen lines so clogged with sludge the functional inside diameter was only 1/8".

I certainly wish someone had taken some vacuum readings.
 
  #25  
Old 02-23-15, 07:08 PM
Member
Thread Starter
Join Date: Feb 2015
Location: USA
Posts: 12
What about switching to the old return line for supply? It has not been used since the tiger loop was originally installed in Oct 95, but has been closed off with a valve where it was disconnected the entire time.
 
  #26  
Old 02-23-15, 07:35 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 13,926
It may or may not go near the bottom of the tank. Many people terminated the return only a few inches down into the tank. One of the previously mentioned push/pull pumps would tell you if the line goes into the oil. You could just hook it up & try it.
 
  #27  
Old 02-24-15, 07:06 PM
Member
Thread Starter
Join Date: Feb 2015
Location: USA
Posts: 12
In a surprising but welcome twist in this tale, today the furnace has been operating without any foam or bubbles in the tiger loop. I can only guess that the earlier CO2 blasts loosened things up enough to finally move on through. Anyway, since the techs around here seem to be up to their ears in cases of no heat, for now I have decided to observe the old adage "If it ain't broke don't fix it!" However, at the next tune-up (if it continues to behave) I will insist on a vacuum check.
 
  #28  
Old 02-24-15, 07:24 PM
Grady's Avatar
Forum Topic Moderator
Join Date: Jan 2005
Location: Delaware, The First State
Posts: 13,926
My guess is the lack of foam is due to warmer weather & the reduced viscosity of the fuel. Presuming you have the tank filled (as opposed to a delivery of X gallons), at the next fill up, add 4 bottles of fuel treatment. With most treatments 1 bottle is a maintenance dose for a 275 gallon tank & 2 bottles is the initial dose. Since your tank is a 550, you would need twice the 'normal' amount.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes