Oil heating 5L/Hr?

[Dev]

I’ve booked an oil delivery which is coming start of next week and Sod’s Law have ran out. Its a bit of a pain but I‘ve a 20l drum I use for the garage so filled it up and stuck it next to the boiler.

Next morning 20L drums empty. Working out the sums I reckon the heating has been on for 4 hours - but you wouldn’t expect the burner/pump to be going constantly for all the time.

Fuel pressure at the pump is 9 bar which I vaguely remember is right. Thing other thing that might be a clue is the boiler room itself isn’t getting all that hot, not as warm as it used to I’m nearly sure.
So I’m wondering is the pump/burner going longer because it’s not getting the boiler up to temp for some reason?

Anyone any thoughts? There’s not a chance I’ll be able to get someone to look at it this side of Christmas I reckon…

 

[8ob]

Doesn't sound excessive, my small diesel space heater in the welding shed can do 20l a day and thats on a stat.

Bob

 

[James1979]

Doesn't sound excessive, my small diesel space heater in the welding shed can do 20l a day and thats on a stat.

Bob

Even when red was giveaway prices 10 years ago having my old space heater on for the day was the thick end of £20.

5l/h doesn’t sound much.

My night heater in the truck does about 1l/h on stat. If I over ride it and put it on maxi chat then it’s easily twice that and that’s a little night heater.

Could you fit a stat or something? Not sure what setup you have @Dev

 

[not done it yet]

It is neither rocket science nor needing a maths degree to read the burner specification and work out how long 20l will last. If you wish to delve deeper, you can look up the energy content of the fuel on the ‘net. The efficiency of the stove/boiler/whatever should have an efficiency rating somewhere - to convert gross energy input to useful energy output.

 

[rtcosic]

OK I'll bite and do some simple sums

Diesel = 45 MJ/kg, density c. 0.84 so c. 38MJ/l

20l * 38 = c.750MJ used over 4 hours

750/ (4*60*60) = c.52kW

Say 80% efficiency then that's about 42kW heat output.

That's a LOT unless you are heating a warehouse, or I've dropped a decimal place somewhere!

Edit: or you haven't found the leak yet?

 

[James1979]

OK I'll bite and do some simple sums

Diesel = 45 MJ/kg, density c. 0.84 so c. 38MJ/l

20l * 38 = c.750MJ used over 4 hours

750/ (4*60*60) = c.52kW

Say 80% efficiency then that's about 42kW heat output.

That's a LOT unless you are heating a warehouse, or I've dropped a decimal place somewhere!

Edit: or you haven't found the leak yet?

Sounds a lot when you put it like that but it’s not incomparable to other burners in similar applications.

My old one cost loads to run because there was no insulation in the workshop at all. So in effect I suppose I was heating the world!

Need more info from OP I reckon….

 

[8ob]

OK I'll bite and do some simple sums

Diesel = 45 MJ/kg, density c. 0.84 so c. 38MJ/l

20l * 38 = c.750MJ used over 4 hours

750/ (4*60*60) = c.52kW

Say 80% efficiency then that's about 42kW heat output.

That's a LOT unless you are heating a warehouse, or I've dropped a decimal place somewhere!

Edit: or you haven't found the leak yet?

My back of a fag packet calc was there is about 10kwh in a litre of kero heating fuel, worst case an old oil boiler could be as low as 60% efficient, 6kwhx20. Decent size gaff with a 150,000 btu boiler running flat out for four hours would/could use about the same in these temperatures.

Bob

 

[mart]

@Dev
Just curious, based on the price you pay for the bulk delivery, what does one litre cost (to heat your place for one hour)?

 

[carbon]

The fuel nozzle in the boiler should be specified somewhere. These are usually rated in US gallons at 8 bar. Changing the pressure also changes the flow rate. If you can find the specs for the nozzle you can roughly work out fuel consumption per hour if the burner is running continuously

 

[hotponyshoes]

Seems high.
Just based on the fact that my 10kva generator uses pretty much 1l/hr on full load.
And a rough guess on how long my domestic oil fills last.

The generator runs constantly whereas the heating boiler kicks on and off but I might do my own sums later as, if it is using 5l/hrs it might be cheaper to get some electric heaters and run them off the generator!!

 

[MetalMonkey]

IIRC as a rule of thumb an average oil burner will go through about 2.5L per hour, so 5L would seem on the high side.

 

[Dev]

Seems high.
Just based on the fact that my 10kva generator uses pretty much 1l/hr on full load.
And a rough guess on how long my domestic oil fills last.

The generator runs constantly whereas the heating boiler kicks on and off but I might do my own sums later as, if it is using 5l/hrs it might be cheaper to get some electric heaters and run them off the generator!!

That’s my thoughts too- even though the heating is on for an hour I wouldn’t expect the burner to run constantly the whole time

 

[rtcosic]

... Decent size gaff with a 150,000 btu boiler running flat out for four hours would/could use about the same in these temperatures.

Bob

150'000 Btu/hr or 44kW boiler is huge to me!

The largest domestic CH/DHW boiler I have ever had was 21kW and that was for a 220m2 (c. 2'400 ft2) detached house. The current boiler is 18kW.

Hence my comment about heating a warehouse. I guess an old leaky farmhouse would be up there with my warehouse.

 

[8ob]

That’s my thoughts too- even though the heating is on for an hour I wouldn’t expect the burner to run constantly the whole time

If 20l of fuel has gone in and you reckon not much heat has come out the boiler must be sooted up and needing a clean. As in the soot is insulating the heat exchanger from the flame and its going out of the flue.

Bob

 

[hotponyshoes]

Humm...
Some quick maths...
I reckon I've used 700l of oil in the last year.
That's mostly over last winter for the heating as I've been running the immersion for hot water all last summer.

So say that 700l was all used between Nov-March for the heating.

That's about 152 days so 4.6l a day.
I'd say the heating is on for maybe 3hrs/day during the week and 6hrs at weekends.
Pure guess but the burner might be running for 50% of the time?
So just under 2hrs a day burning time on average. (4hrs running/day)

= 1.1l/hr.

My place is not very big but its an old bungalow with solid stone walls and a poor layout for even heating. It's only really the living room that warms up properly and we are never in much.
I could imagine that I could easily double the usage if the place was heated properly for the same amount of time and double that again if I wanted heating on in the morning and before we come home from work. If it was 3/4 bed with the same standard of insulation and doing hot water for a family as well then maybe 5l/hr would be about right?