Oil heating line to the house

Daz_

Hi . I live in a detached house and use oil for central heating . Boiler is located about 20 ft from the house . In the cold weather I noticed that the underground line running from boiler to the house was thawing the ground above it so that you could trace it all the way to the house ( pebble surface ) I don’t know how Deep it runs .
Would this kind of heat loss be normal ? I find the oil usage pretty high .
Built around 2004.

Any advice and opinion welcome

Thanks

Lenar3556

Hard to quantity the heat loss based on that evidence, as it wouldn’t necessarily take a huge loss to do what you are saying.

Does the boiler need to be 20ft from the house? Such a location is lightly to reduce the efficiency of the system unless very comprehensive measures were taken to insulate the pipe run at the time of installation.

A good heating engineer will be able to calculate the heat loss between the boiler and house. With this information you could then decide if it’s worth doing something with the pipe run or boiler location.

seamus

Typical? Yeah. Desirable? Not really.

When we had our extension built the builder stumbled across the pipe for our neighbour's boiler, which was located at the end of their garden. Rather than going down into the ground and directly to the house, the pipe ran about 6 inches deep around the perimeter of the garden before going into the house. God knows how much money they spent heating their garden and the boundary wall over the years.

The work to do anything about it might cost you more any long term savings though.

Another thread here on it, with some suggestions in terms of packing the ground around the pipe with sand or something else very porous.

https://www.boards.ie/vbulletin//showthread.php?p=90688729

lemonkey

Daz_ wrote: »

Hi . I live in a detached house and use oil for central heating . Boiler is located about 20 ft from the house . In the cold weather I noticed that the underground line running from boiler to the house was thawing the ground above it so that you could trace it all the way to the house ( pebble surface ) I don’t know how Deep it runs .
Would this kind of heat loss be normal ? I find the oil usage pretty high .
Built around 2004.

Any advice and opinion welcome

Thanks

Not normal and that's why your heating bill is probably so high!

You can get pipe insulation and wrap it in foil (all available at local merchants). Only problem is you'll have to carefully hand dig around the pipe and do it yourself.

Daz_

Lenar3556 wrote: »

Hard to quantity the heat loss based on that evidence, as it wouldn’t necessarily take a huge loss to do what you are saying.

Does the boiler need to be 20ft from the house? Such a location is lightly to reduce the efficiency of the system unless very comprehensive measures were taken to insulate the pipe run at the time of installation.

A good heating engineer will be able to calculate the heat loss between the boiler and house. With this information you could then decide if it’s worth doing something with the pipe run or boiler location.

I hear you about the distance but that’s what we have inherited. I suppose could look at relocating closer but it’s all money !

Daz_

seamus wrote: »

Typical? Yeah. Desirable? Not really.

When we had our extension built the builder stumbled across the pipe for our neighbour's boiler, which was located at the end of their garden. Rather than going down into the ground and directly to the house, the pipe ran about 6 inches deep around the perimeter of the garden before going into the house. God knows how much money they spent heating their garden and the boundary wall over the years.

The work to do anything about it might cost you more any long term savings though.

Another thread here on it, with some suggestions in terms of packing the ground around the pipe with sand or something else very porous.

https://www.boards.ie/vbulletin//showthread.php?p=90688729

Ok appreciate that will take a look

Daz_

lemonkey wrote: »

Not normal and that's why your heating bill is probably so high!

You can get pipe insulation and wrap it in foil (all available at local merchants). Only problem is you'll have to carefully hand dig around the pipe and do it yourself.

I’d imagine the water is cooling a lot so trying to keep temp is making boiler work harder no doubt.
I’m wary about going near the pipe , I’d probably do more harm than good

gctest50

lemonkey wrote: »

..........

You can get pipe insulation and wrap it in foil (all available at local merchants). Only problem is you'll have to carefully hand dig around the pipe and do it yourself.

Waste of time, all you'll end up with is soggy insulation

The boiler away from the house is good if it ever leaks oil, better than knocking walls


Anyway, this sort of thing is available :


https://touch.adverts.ie/plumbing-gas/terrendis-pre-insulated-underground-pipe/13163620

Wearb

Most plumbers around here used to just put foam insulation and wraps if silage tape on them. insulation got sodden and was then useless.

One guy used to use sewage pipe and put the insulated pipes through that, with properly sealed 45 degree bends to keep it all dry. I copied his method a few times. Great job and give a little warning if digging,

MicktheMan

Daz_ wrote: »

Any advice and opinion welcome

Thanks

The last time I did a test on such as setup I measured roughly a 30% loss of temperature between boiler output and entry into the house. The line loss was consistent on both the flow and return. Boiler was less than 15m from the house iirc.

Either move the boiler or replace the flow / return with proper insulated pipework (Calpex or similar) is my suggestion.

Daz_

MicktheMan wrote: »

The last time I did a test on such as setup I measured roughly a 30% loss of temperature between boiler output and entry into the house. The line loss was consistent on both the flow and return. Boiler was less than 15m from the house iirc.

Either move the boiler or replace the flow / return with proper insulated pipework (Calpex or similar) is my suggestion.

That’s very interesting .did you calculate how that affected oil consumption ? Not sure if it’s as simple as saying boiler then used 30% more oil ? That would be massive . It’s a 2004 boiler and doesn’t look like it’s suitable to be placed outdoors so not sure if it’s work the expense involved there for a move .

Get access to as much as the flow piping as possible as insulate properly probably my best option

MicktheMan

Daz_ wrote: »

That’s very interesting .did you calculate how that affected oil consumption ? Not sure if it’s as simple as saying boiler then used 30% more oil ? That would be massive . It’s a 2004 boiler and doesn’t look like it’s suitable to be placed outdoors so not sure if it’s work the expense involved there for a move .

Get access to as much as the flow piping as possible as insulate properly probably my best option

I did but cannot recall the exact calc. I do remember though that the calculated percentage oil wasted was greater (~10%) than the temperature drop percentage because of the relative ambient temperature of the soil versus absolute line temperature drop and boiler efficiencies. So actual oil lost to the ground was greater than 30%, perhaps 33%:eek:

Lenar3556

30% of total heat produced would be really extreme.

As an approximate guide of a worst case scenario - 1” Uninsulated Copper looses about 100W per metre when carrying water at 70oC in an ambient 10oC.

The loss from the return will always be less because it will be at a lower temperature.

So a worst case for a boiler 20ft from the house, assuming 1” copper pipe, running at full temperature, and no insulation whatsoever would be about 1KW per hour of actual boiler operation. In oil terms at the moment, even assuming a very low efficiency boiler is about €0.07 per hour inclusive of VAT.

When you consider that there is likely at least some insulation, the pipe work is more likely to be plastic and it may well be less than 1” also - €0.04 per hour of nett loss is probably a realistic guess.

That’s likely to be north of €50 a year, so considerable - but you should have realistic expectations about how much oil you are likely to save by upgrading.

Even with the likes of Calpex, you are still taking about 10W per metre of heat loss on a 1” pipe

Wearb

Are you talking about losses from a copper pipe in air. This is most likely in insulation sodden with water, in water logged ground.

I know what it can be like, having repaired one a few years back.

Lenar3556

Well these a very approximate figures, just to put some perspective on it.

Yes - these are typical values for free air. Direct bury in unprotected soil conditions is likely to reduce the heat loss as the soil itself can act as an insulator, although in some soil conditions, it can go the other way. I think at a 600mm depth the effect of burying a pipe can impact it’s W/m loss by a factor of anywhere between 0.6 and 1.2 dependent on the conditions.

I suppose the point being that the customer should try to assess in advance the impact of certain energy saving works in order to get best return on investment. While a clear case of energy loss, there may be bigger offenders within the house.

Wearb

I still think that pipes in sodden insulation in wet soil (which it mostly is in winter) creates huge heat losses. I don't expect that wet soil and insulation offers much in the way of reducing heat loss. But I am only going on anecdotal and not scientific evidence, so you could be right.