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Participant

Join Date: Dec 2011
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Drop in Ldo Pressure in Winter

01/23/2016 9:03 PM

Hi

In winter especially at night and temp. Around 20 deg.C, light diesel oil pressure at boiler end drops to a low value. If we try to take guns, we r unable to do so easily and requires several tries. There is no long recirculation for ldo but there is a short recirculation in pump house where the pressure gets maintained at rated value. There is no insulation on ldo line... Is there any solution to keep the pressure maintained at boiler end...?

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#1

Re: Drop in Ldo pressure in winter

01/23/2016 9:18 PM

Heat seems a logical solution.

Maybe a PD pump at the tank/supply end.

A simple diagram would help to understand the system.

You could always pay someone for advice and have them visit the facility.

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#2

Re: Drop in Ldo pressure in winter

01/23/2016 10:28 PM

I agree with Lyn; heat seems like the answer.

You note no insulation on the line, so it seems like you already suspect that is a problem. Insulation is probably a good idea. There are also inexpensive electrical pipe heaters with thermostats, so that heat only kicks on when it is cold....you can even get these at home imovement stores.

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#3

Re: Drop in Ldo pressure in winter

01/23/2016 10:30 PM

Is a strainer or screen getting plugged somewhere, leading to pump cavitation? Any water or organisms in the fuel?

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#4

Re: Drop in Ldo pressure in winter

01/24/2016 3:13 AM

Yes.. Heater is one solution, but risky as local heating can be high and making it as a tracing line will be expensive.

Please consider that v have to make arrangements for say 15-20 days in a year that too as a preventive measure.. Planning for providing tracing lines of hfo at some points on ldo line. Can u suggest possible hazards in a that.

Thanks for ur response

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#6
In reply to #4

Re: Drop in Ldo pressure in winter

01/24/2016 10:39 PM

If you need to heat diesel that is just sitting in pipes to prevent it from getting too cold then heat trace is a good answer.

Contact your local heat trace agent for a quote, just don't skimp on the pipe cladding (you need it to get the heat trace to work effectively).

Yes it may be a slightly expensive solution, but it is a reliable solution. There may be others but they will likely be more labour intensive (and potentially less safe).

Jack - Yea, I also design and sell heat trace systems.

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#5

Re: Drop in Ldo Pressure in Winter

01/24/2016 12:54 PM

A return line so the oil circulates while the boiler is off line is an option.

Keeping the boiler on low fire during the night is also an option. The bonus, it would speed up the morning restart and save thermal shock on the boiler.

Both cost money……….. The low fire option involves no capital outlay.

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#7

Re: Drop in Ldo Pressure in Winter

01/25/2016 2:53 AM

Assuming its the same problem as Diesel vehicles get each cold spell, which used to get fixed with say a heater placed in or before the diesel filter, to prevent flakes of paraffin wax forming and blocking the filter.....

Nowadays, here in Europe, they start producing winter diesel for vehicles, well before winter arrives. This has far less paraffin in it OR has some chemical that dissolves the flakes before they even form or similar I would guess.

Many years ago, we used petrol mixed in at around 5-10% in the diesel, to stop the problem, but as petrol is not a lubricant, it wears the precision pumps in modern engines.

If there are no such pumps in your system, you could add some petrol and see what happens, but if its a huge tank, you might want to organise a smaller tank, to reduce the sheer amount of petrol needed till the weather warms up...

Or simply warm up the liquid using one of those car filter diesel warmers.....say running from a 12 volt power supply.....it would be cheap and easily installed.

Put it (and any filters or sieves), just before the boiler, or at least inside your house....so that the fuel does not cool down again and block the filter up!!

But as its not proven exactly what the problem is, I am only guessing.....But Fuel oil for central heating, is not designed for low temperatures even here......so it is a possible scenario.

I hope this helps......

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#8

Re: Drop in Ldo Pressure in Winter

01/25/2016 10:34 AM

Do You really mean 20 deg C which equals 68º F why would that be too cold?

otherwise

Could You add another filter housing without a filter and use the Heat wire as previously suggested to preheat just this new housing so cold fuel does not enter your filter unit?

Don't forgot the thermostat.

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#9

Re: Drop in Ldo Pressure in Winter

04/02/2016 7:55 PM

When I teach boiler classes I make it a point to stay with this premise. " the answer to every good question is in the question". You have asked a very good question and answered it as well. Insulate, recirculate and maybe add a fuel additive if your location code allows. Employ your thoughts and return here with your results.

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Andy Germany (1); jack of all trades (1); ksajay (1); lyn (1); miketheboilerguy (1); TonyS (1); Tornado (1); truth is not a compromise (1); zerkman (1)

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