oil freezing point ?

[ar22]

went to a 3 year old Warmflow oil bluebird boiler today.

no heat first thing this morning, pressed the reset but only a bit of life then lock out, suspected oil flow was an issue, put a pressure gauge on and got her fired up,

fitted new jet, cleaned photcell etc

pressure was there (8bar) but unsteady then after 20 seconds pressure would fall to zero and flame would fail, motor kept going and then oil would turn back on and ignited fine for a further 20-30 seconds. this all continued for 3 or 4 minutes running longer every time with it finally running fine and pressure perfect. Boiler now fully serviced and running perfect.

initially I presumed a faulty oil pump but had doubts, it was almost as if the oil flow was low

what temperature does oil start to freeze, I am convinced this was the problem

or any other ideas, solenoid maybe ?

 

[bert large]

Not sure about heating oil but I know diesel used to start going "waxy" at around -10 degrees C. It isn't a problem with road diesel nowadays due to additives which prevent this.
I assume heating oil, being similar to diesel, has similar additives but maybe you have a batch that doesn't have these additives.

 

[Blackcatgas]

Yes it freezes, it used to at my mums as 3m of copper pipe was exposed, I lagged this with grey lagging expecting it to last 6mnths, its still intact 10yrs later.

 

[WHPES]

Kerosene freezes about -41 degrees C

More likely there is some ice in the line.

 

[Blackcatgas]

Kerosene freezes about -41 degrees C

More likely there is some ice in the line.

Erm... yes my mum lives at the north pole.... lol! You learn somthing new on this forum everyday.

 

[ar22]

cheers

sort of bugged me that I "fixed" it without actually getting an answer what was actually causing the problem

 

[Blackcatgas]

Just googled the freezeing point of heating oil, the point at which it turns to gel and can stop flowing is -9

 

[dontknowitall]

I've read freezing point is -30 deg and -22 deg and now -41 deg.

Obviously not cold enough in this country ... yet!

But ... water can get into oil lines and if this freezes then you'll have the problems you have above. I had one a couple of weeks ago and asked customer for a towel and a bowl of boiling water. Placed hot towel over oil line and ... hey presto ... working again. What puzzled me was how it went well past the ignition cycle (up to 2 minutes or so then locked out). Turned out that every time I took the burner off there was just enough oil coming through to fill the internal section of the oil line and flexible line but not enough coming past the fire valve (due to freezing).

Hope this helps.

 

[Blackcatgas]

I've read freezing point is -30 deg and -22 deg and now -41 deg.

Obviously not cold enough in this country ... yet!

But ... water can get into oil lines and if this freezes then you'll have the problems you have above. I had one a couple of weeks ago and asked customer for a towel and a bowl of boiling water. Placed hot towel over oil line and ... hey presto ... working again. What puzzled me was how it went well past the ignition cycle (up to 2 minutes or so then locked out). Turned out that every time I took the burner off there was just enough oil coming through to fill the internal section of the oil line and flexible line but not enough coming past the fire valve (due to freezing).

Hope this helps.

Right Iam out of my depth here but, it might freeze at -41 but before that temp it can turn waxy and stop flowing?

 

[djboyd]

Yes

It is not the 'freezing' point that is the issue, it is the waxing point. it may then start to block small channels and filters.

 

[dontknowitall]

Good ole tinternet ...

Here's a little info - suggesting waxing point is -9 deg. I think it's from across the pond but it should be near enough the same stuff as kerosene.

A Definition of The Cloud Point for Home Heating Oil - No. 2 heating oil:

Heating oil or diesel fuel waxing or clouding or gelling begins to occur at about -9 degC or about 16 degF. The cloud point for heating oil is defined as the temperature at which a cloud of wax crystals first appears in a fuel sample that is cooled following the procedure in ASTM Standard D2500. In more practical words, home heating oil will probably flow through the oil piping, filter, and oil burner without an operating problem down to about -9 degrees Centigrade or 16 degrees Fahrenheit.

 

[WHPES]

The "heating Oil" over the pond is usually Class D Gas Oil (diesel fuel) which will start waxing at about -9

Kerosene will start waxing at about -30

Much depends on the additives. Small amounts of Kerosene are added to Gas Oil to lower the waxing temperature.

 

[Blackcatgas]

You can get class D here though?.

 

[ar22]

slight update

same boiler was turned off for 6 hours last night

owner got a bit paranoid at 5am and turned it on but no go at all, he went out to the garage and hit the reset button

boiler fires up and runs and goes out to lock out, press reset again a couple of times and then keep the motor going but he can hear flame going out but it refires itself this continues for 10 minutes gradually getting longer running each time

then it all clears and all runs perfect and still is

its at least minus 10 here, pipe is buried under ground all way in to garage

we have no idea how deep it is but if its only down a bit we think if the flow stops for a period its geling up, ground around here is frozen pretty deep

down side to this is that in the end the pump is going to be wrecked if we continue with this coaxing to get it started

has heat is on 24hrs now with the house stat low but at a level where the system wont go too idle for any period of time

I have a spare complete good burner waiting in the wings if all goes bad on Christmas day to save divorce



Whats your opinion on this Cropie as you are in sunny Portadown, frozen line or just bad pump

roll on the thaw

 

[dontknowitall]

Could be the pump but with these temperatures I'd suggest it's a frozen line. I wonder, although it's buried, whether it's at/in the water table and whether this is frozen? Unlikely but sometimes you have to think outside the box.

 

[ecowarm]

Have come across waxing here in kerosene about -9c