Oil Suitability - Testing?

[GerryADS]

Hey Folks,

Fairly new in here from Scotland 

Have been running a kerosene burner which I converted to WMO using a siphon nozzle & fitted with a DELAVAN 30609-9 - 0.85GPH(US).

It has PID controlled Nozzle heater, and PID controlled feed tank, the first year, I guess I got lucky with the oil I received & filter technique, but lately it can be hit or miss with regards the suitability of the oil.

Firstly the oil is allowed to stand for a few months (inside) and the settled water is drained, oil is then pumped to a higher tank and a slow gravity feed passes through several strainers, before entering a Racor/Parker RFF Water Separating Fuel Filter Funnel.

However the last few batches of oil (unknown) seemed to have been difficult to ignite or keep lit, I've checked over all the burner side of things, and all is well (proof tested with known good WMO & works fine) I suspected emulsified/suspended water, but even if I turn the PID heater up in the feed tank (where the siphon is fed from) then whilst I can sometimes witness water boiling off, eventually settling down to a very hot (160C) without any steam coming out, it still proves difficult, I have found that I then have to turn the PID nozzle temperature way up, but even with that, it will sometimes fail to stay lit as soon as the ignition spark is cut. The only way I have found to keep the difficult oil lit after ignition is off is to run the nozzle with almost 2.5X the air pressure, however that is far too much heat for the small size of combustion chamber (water jacket heating boiler/furnace)

Therefore my question (after the long-winded intro) is what are you guys using to prove/test the suitability of the WMO, so as to not go through the pain of all the preparation of a less than ideal WMO?

I have some ISO32 Hydraulic oil which I though should burn easier than WMO from an auto shop, but found it needed a reasonable amount more tank & nozzle heat, is this to be expected?

What temperatures do you all use at the nozzle and tanks with what oils please?

Thanks for listening 

Gerry

[Russ]

Greetings  Gerry!

I cant say that I have ever had problems with getting oil to burn.  Maybe I have just been lucky.  I run my PID nozzle heater at 200F or 93C and havent had any problems.  If you run known good used motor oil through it does it burn fine?  Is it just with this poor quality that you are having the problem?

[GerryADS]

Hi Russ,

Apologies for the slow response, managed to pick up a dose of covid!

Thanks for the welcome and input.

I had thought it was an oil quality issue, as replacing the questionable oil with known oil seemed to be back to working as it should, however I did notice that our heating radiators were not as warm as I'd expect, which made me query the system, so I went back to basics.

Somewhat embarrassed with my oversight, but it turns out the pressure gauge on my regulator (dedicated to the burner siphon air supply) was out by about 6psi, therefore I had adjusted the pressure according to my known reference value (normally 5.5psi) but clearly it was barely lifting and atomizing any fuel.

I worked out that the problem was due to me having fitted a 15psi gauge (so as to more accurately see small variations rather than the standard fitted 150psi unit) however what I witnessed is that when the 125psi supply from the compressor main circuit is connected initially there is a huge spike before the regulator is able to control it, therefore the needle whacked off the end stop, and clearly jumped some teeth on the rack & pinion, however it still returned to zero, which is what caught me out.
I've now replaced it with a digital gauge rated to 250psi, but can still see in 0.1psi resolution, so hopefully wont make that mistake again.

Now it appears that what I thought was inferior fuel works just as well as my go to known good wmo source.

Thanks again,

Gerry

[Russ]

Good to hear that you figured out the problem Gerry.  Sounds like a nice digital gauge you got a hold of there, that should help keep track of what is going on with your pressure.