Oil Tank Below Boiler Level problem

[thediscobison]

Hi,

Recently on the advice of a plumber we moved our oil tank level from above the level of the tank, to further down our garden. We were told that it would be fine as he would use a tiger loop which would draw the oil up to the boiler no problem.

The bottom of the oil tank is around 2.5/3 metres below the level of the boiler, and a distance of approx 25m away. This is well within the specifications of the tiger loop (up to 13ft in height and at least 25m in length)

Now after much problems getting and keeping the boiler going, he is suggesting that we need to move the tank up by approx 2 or 3 feet as "our burner pump is not strong enough to draw the oil up that height." The boiler was cutting off as it was being "starved of oil"

It has been suggested to me by another plumber that we should consider a two pipe system, as he would not have considered using a tiger loop for the size of drop we have. Surely a two pipe system would still require the burner pump to be strong enough to draw the oil up the same height?

Are there any solutions which anyone would recommend to fix this? I don't want to move the oil tank (and I hope I won't need to)

 

[ecowarm]

what size is the pipe to the tiger loop?

 

[thediscobison]

ecowarm: I guess standard copper pipe size 3/8s maybe?

 

[WHPES]

IMO your guy is probably talking rubbish. The MIs for the boiler (or a quick phone call to the manufacturer) would give the maximum height for the boiler above the tank.

More likely to be the problem is the pipe diameter being too large. What is the diameter of the pipe? It should be no greater than 8mm. 6mm would be the ideal. If it's 10mm (or even 15mm) theres your problem - It's just too hard to suck up the fuel and you get a vacuum in the pipe.

Narrower diamater pipe means less effort to suck and faster moving liquid so no accumulation of air (have you ever seen how TINY the fuel pipe to your car engine is?)

Replace the pipe with 6mm pipe. Tigerloop should bw fine, and get someone else who knows what they are doing this time.

Was your oil engineer registered? I seriously doubt it if he used 10mm or larger pipe? All the design requirements form part of the OFTEC manual and if they had followed it then it would be working. All registered technicians have that info drummed into them.

If the pipe diameter is too large, the technician should replace it at his expense as it is not to OFTEC specifications.

Pipe must be plastic coated. As 6mm and 8mm pipe is delicate it must be buried in a duct. Usual OFTEC rules regarding depth, sand, warning tape etc apply.

 

[ecowarm]

I agree with WHPES 8mm max

 

[SimonG]

Also have a look at the filter on the tank (if it has one), customer had new tank (plastic bunded) installed at an extended distance to the boiler with tiger loop, burner about 2m above tank. He had a number of engineers look but it kept starving itself of oil. Turned out that he had tipped the contents of the old tank straight into the new using a tractor with forks. The filter was goosed because of all the crap in it. New filter and everybody automatically thought it would be clear.

 

[kimbo]

According to Anglo Nordic a Tigerloop will lift 3.66m with a horizontal run of 30m using 10mm pipe. I have to say I have never had a problem and always use 10mm pipe, its difficult to get 8mm pipe around here.
The most important thing is to make sure the oil pump has been changed to cope with the 2 pipe system and that you use flared fittings to stop sucking in air. The system obviously works because you have had it working so the problem you are experiencing would sound like air being sucked in and therefore after a period on inactivity the vacuum is lost and the tigerloop needs to be reprimed.

 

[WHPES]

Surely the installer pressure tested the system before commissioning so if there were any leaks would have found them?????? Or are we talkng about a right cowboy here??

10mm pipe is defnintely not suitable for lifting oil. Kimbo - You have been lucky and got away with it but it is against regs and in any case very bad practice and should not be used in such circumstances. You defnintely won't get away with it for the height the OP is talking about - I have come across several installations where it has caused problems and nothing to do with leaks. No problem getting hold of 8mm or 6mm pipe here - granted you have to order it in advance, but still no problem.

 

[thediscobison]

Surely the installer pressure tested the system before commissioning so if there were any leaks would have found them?????? Or are we talkng about a right cowboy here??

10mm pipe is defnintely not suitable for lifting oil. You have been lucky and got away with it but it is against regs and in any case very bad practice and should not be used in such circumstances. You defnintely won't get away with it for the height the OP is talking about - I have come across several installations where it has caused problems and nothing to do with leaks. No problem getting hold of 8mm or 6mm pipe here - granted you have to order it in advance, but still no problem.

OK so I had a look at the pipe and tried to measure it as best I can
The white plastic on the outside says copper tube 10 * 0.7
to my eye using a tape measure the diameter looks about 10mm.

My burner is a Max Firebird C26 50/90
The pump(?) on it appears to be a Danfoss Type BFP 11R3

It has been a bit of a saga, right now my plumber is messing about trying to find the level at which it will draw oil without cutting off using a different pipe and a small container of oil. Currently it is drawing from that about a foot in height and about 15m in length. We are wasting our time I think as I really don't want to move the tank (esp now that it is full.) Two days ago we moved the small container down to a drop of maybe 6 foot (hard to say without actually measuring so this measurement is by eye) to the bottom of the container. The boiler ran for a few hours that night. Then in the morning I tried to turn it on and it cut off immediately. To my plumber this was "proof that it wouldn't draw from that height." Then to get the boiler going again he had to move the oil right up to the boiler - I guess to prime the pipes.

How can we be sure that a thinner pipe will work? Would you recommend sticking with the tiger loop, or considering a two pipe system?

Are there any special valves that are needed on the fuel line to stop the oil running back down into the tank? What keeps the oil at the right pressure in the pipe once it is drawing oil? As you can tell, I'm not convinced my plumber actually knows what he is doing

Was brand new pipe work he put in, and had initially tried to avoid having any joints in it as he didn't want the chance of them failing and drawing air. He would not have pressure tested it. Now the tube has multiple connections on it.

And in response to another post: we moved the tank, so the oil would have had 10+ years (at least) of sludge and whatever else usually collects in the bottom of your tank. But we got 1100 litres of oil, Right now there is no filter on the (temporary) fuel line or the intended line.

 

[SimonG]

So the boiler only starves after a long period of non operation?

 

[ecowarm]

The use of a smaller diameter pipe is the only option, I had the same problem last year with a couple of boilers that had been fitted at a school, wall mounted grants side by side and the installer had run two supplies from the tank to two tigerloops and then to the boilers.
One boiler was on a 10mm and the other was on an 8mm so I altered the pipe work so the 8mm fed both tigerloops, both boilers now run perfectly, but I did find a couple of leaks between tigerloops and boilers and was allowing the oil to drain back to the tank overnight. This is now resolved. Stick with the tigerloop.

 

[thediscobison]

So the boiler only starves after a long period of non operation?

not necessarily a long period of non operation - overnight so 10/12 hours

 

[thediscobison]

The use of a smaller diameter pipe is the only option, I had the same problem last year with a couple of boilers that had been fitted at a school, wall mounted grants side by side and the installer had run two supplies from the tank to two tigerloops and then to the boilers.
One boiler was on a 10mm and the other was on an 8mm so I altered the pipe work so the 8mm fed both tigerloops, both boilers now run perfectly, but I did find a couple of leaks between tigerloops and boilers and was allowing the oil to drain back to the tank overnight. This is now resolved. Stick with the tigerloop.

Is there a good way to verify that the thinner pipe will work? He'll probably try and talk me out of ordering/buying the length of copper piping

 

[ecowarm]

Ask him to show you his OFTEC books and then work out the pipe size from the book, assuming he is OFTEC registered

 

[WHPES]

I doubt he is registered as if he was he would have known better. Like I said if it had been installed properly, a pressure test (as specified on the OFTEC form) would identify any leaks. Worse still if he isn't kosher, your relocated oil tank is unlikely to have been installed to regulations and if you didnt already know is subject to Building Control and if your local authority BC dept hasnt been notified you could run into trouble.

Easy way to tell is you should have received a Building Control certificate from your local authority if it has been done properly. You should also have a copy of his Form CD/10 for the installation and a T1/133 form for the risk assessment for the tank. If you have not received one, then ask him for one.

Even if an existing tank is relocated it needs the above.

If he's not registered and youre getting nowhere, then I would kick his butt and get a registered technician in who knows what they are doing. I would also get the registered guy to check the rest of the installation to ensure it is safe and to standards.

 

[kimbo]

Whpes there are no regs that say you can't use 10mm pipe. Anglo Nordic state the max sizes and run lengths in their catalogue. Granted It may need a smaller.dia pipe but I suspect he has not got airtight joints. I must have been lucky hudtrds of times when I fit them with those odds I should do the lottery and retire on my winnings.

 

[Gray0689]

10mm should be fine for this installation

 

[SimonG]

Agree with Gray0689 and Kimbo, redo the joints and get them air tight.

 

[WHPES]

Whether or not it has worked for you, look at the table in your OFTEC Installation Requirements book and if you disagree, take it up with OFTEC. Personally I do all my installations to specification and there's no comebacks on you, and I use a lot of 8mm tube. (also 8mm is cheaper!)

 

[thediscobison]

the saga continues. tonight after the heat being off for maybe 18/19 hours, the boiler didn't fire first time and I needed to hit the red button. Bear in mind this is from a temporary oil drum only 2 or 3 foot lower than the boiler, and approx 15m length of pipe. So what are the possibilities here:

- Non air tight joints causing a loss of pressure in the pipe?
- A faulty pump?
- Some other issue (e.g mis connection in tiger loop install, misconfguration etc.)?

For those asking : I don't know if the guy is OFTEC registered - I'm beginning to doubt it. He didn't pressure test either pipe before install - I guess there is a tool you would usually use to do this? As a plumber he is usually very reliable.

 

[Gray0689]

I'd be checking the 2 flexi pipes are right way round and check to see if grub screw inserted

 

[WHPES]

One of these - every plumber should have one.

One of the tick boxes on the CD10 Installation Sheet is for pressure testing.


Rothenberger RP50 6.1004 Pressure Testing Pump 60 Bar - rp50 - Pressure Test Pump - PLUMBING TOOLS - Trade Counter Direct Ltd

 

[GussyFinknottle]

10mm pipe is no problem at that depth and distance,if not i would have had a lot of angry calls over the years.I have never personally used 6 or 8mm as the pump on the burner is not really designed to pump oil from a tank.its likely you have air being drawn through the compression fittings when the burner switches off and your fuel load goes into vacuum mode.Make sure the bypass grub screw is fitted in the fuel pump of the burner.I have often fitted 2 tiger loops in tandem when i have a difficult situation,instructions on how to do this comes with the tiger loop

 

[thediscobison]

One of these - every plumber should have one.

One of the tick boxes on the CD10 Installation Sheet is for pressure testing.


Rothenberger RP50 6.1004 Pressure Testing Pump 60 Bar - rp50 - Pressure Test Pump - PLUMBING TOOLS - Trade Counter Direct Ltd

Thanks WHPES, I'll check with him later. Hopefully we can get this resolved and working without much more hassle.

Quick question, are there anything in the regulations about burying the pipework between tank and burner? Is it ok to leave part / all exposed?

 

[thediscobison]

One of these - every plumber should have one.

One of the tick boxes on the CD10 Installation Sheet is for pressure testing.


Rothenberger RP50 6.1004 Pressure Testing Pump 60 Bar - rp50 - Pressure Test Pump - PLUMBING TOOLS - Trade Counter Direct Ltd

Thanks WHPES - I'll suggest this to him and hopefully we can get it sorted shortly.

Quick question : are there any regulations with regards to the pipe needing to be buried in the ground or not?