Depth of pipes from boiler

Ponder013

The plumber is currently installing an oil boiler in my house.

He's run pipes to and from the boiler into the house in a trench that is maximimum three inches deep, he says he's going to lag them, but surely they should be deeper than that? Knowing nothing about plumbing I'm not sure if I should say it to him before he goes any further and fills in the trench

Sparkpea

They should have been lagged in armoflex from the start and yes 3" is nowhere near enough. At least 12" depth minimum I would say, but I'd be much more happier at 18"!

Further down you go the better and less chance of freezing. I've heard of some people now doing 24" as standard.

Plumberboy

ye know what i wouldnt agree with the further down the safer, theres been so many times ive had to kango pipes that are well under the ground and pipes have burst, if he could go another couple of inches it would be grand.....And he could be using qualpex pipe up until the last metre of the boiler and once its lagged it never seems to burst half as much in a big freeze for as copper does for example..

heinbloed

First of all: it's a mistake to install a boiler in a place which shouldn't be heated, the boiler being a radiator itself.
Second: if flow and return pipe have to run in the soil then they should not only be insulated against temperature loss but also against impact. Simple foam like "armaflex" would be crushed under the impact of (soil)weight.
Such an insulation method would need further impact protection, for example with a sewer duct/-pipe.
There are special pipes for this under ground purpose available.

"Armoflex" pipes are only temperature resistant to 60 degrees Celsius according to the manufacturer's information, maybe Sparkpea meant something else ?


What the 'plumber' recommends to the OP (3"deep in ground) is certainly not the correct method.

Sparkpea

yeah I would duct them as well and that would protect the armoflex (lagging that I was referring to). Also would use 19mm armoxflex. I'm not up with the specifics about what temps it withstands but I'd use it over tubolite, certainly on show anyway. There could be more effective methods out there these days but nothing I'm too familiar with.

Ponder013

I should have said, the boiler is in the boiler house, about eight feet from the house - it hasn't been installed yet - he's just drilled holes for the pipes, dug the trench between the house and the boiler house and laid them in. There are two qualplex pipes and a conduit for electric, but they aren't conected to anything yet.

The trench is very close to the shore for the guttering and I was wondering if they didn't go deeper for fear of interfering with the drains and making more work for themselves.:)

martin46585

Have a look at calPex duo piping, especially for this type of application, the method that he intends installing will be something similar to underfloor heating, only outside, come the winter, if the last two are to be the norm, you will have no trouble identifying where the pipes are buried............

Carlow52

heinbloed wrote: »

"Armoflex" pipes are only temperature resistant to 60 degrees Celsius according to the manufacturer's information, maybe Sparkpea meant something else ?

Have u a link for this

the stuff I use is found here
http://www.armacell.com/www/armacell/ACwwwAttach.nsf/ansFiles/ClassOArmaflexUKROI.pdf/$File/ClassOArmaflexUKROI.pdf

Carlow52

Ponder013 wrote: »

The plumber is currently installing an oil boiler in my house.

He's run pipes to and from the boiler into the house in a trench that is maximimum three inches deep, he says he's going to lag them, but surely they should be deeper than that? Knowing nothing about plumbing I'm not sure if I should say it to him before he goes any further and fills in the trench

This is completely unacceptable and needs to be resolved now. does this cowboy have a horse?

As well as being insulated the insulation need to be kept dry as if it gets wet it will be NFG

heinbloed

@ Carlow52 who asked:

Quote:
Originally Posted by heinbloed View Post

"Armoflex" pipes are only temperature resistant to 60 degrees Celsius according to the manufacturer's information, maybe Sparkpea meant something else ?
Have u a link for this

Here the Armoflex link:

http://www.ralco-tubings.co.uk/hoses/search/search-ARMOFLEX-item-253.html

Armaflex (foamed PE) is suitable for higher temperatures.

But NOT in wet conditions! It takes up moisture when burried in the ground, that is my own experience. The reason for this is that in the ducting water will accumulate, puddles only.

Now the the insulation foam gets warm and cools down, this will make it expand and shrink. And this in turn will create negative pressure in the foam, the shrinking of the foam bubbles will suck-up water. Like a sponge.

A common problem with foam based materials, most installers and architects and civil engineers pretend to haven't heard about.....

I burried more then 40 meters of armaflex (19mm thick insulation/25mm internal diameter) in the ground, ducted in sewer pipes against compression. 3 years ago that was. The ground temperatures are normal, burry depth at about 30-50 cm. Temperature in the 22 mm tubes between 5 degrees and 100 degrees Celsius, a solar thermal installation. The Armaflex shrunk and took up water, it needs replacement now.

Another piece was inserted in a water tank, the ST storage with permanent water sourrounds, temperature exposure between 20-100 degrees Celsius, water only, no glycol or antioxidant. It was done within 1 year, turned into a custard like substance. It sunk in the water...

Note that both installations do NOT put loadbearing pressure onto the Armaflex PE material I used, the ST tank being unpressurised and the soil ducting well ducted.

Another installation equipped with armaflex insulation material was the solar station, the cast iron air bubble seperator at the return. The Armaflex melted to it, the exposure temperature maximum 107 degrees Celsius for a very short time. Usually well below boiling temperature.

For the price they charge for it is a very bad product.
The material is right **** for this purpose.
The (temperature-) tollerance given by the Armaflex manufacturer is ONLY for dry situations and ONLY for short term exposure!

I do not understand how ST installers use it, they have no idea what they're doing. My ST-'district heating' system is an open one, no pressure on it means max. temperatures at ca. 100 degrees Celsius.
The closed ST toy systems installed on Irish roofs will reach easily 150 degrees Celsius, during stagnation well above 180 degrees Celsius.
Here only a mineral based product will resist the strain, esp. when the piping is running exposed at the outside of a roof/building.

My Armaflex insulation (installed out in the open) had shown externally serious deterioation, the surface crumbles away if not protected against UV light.
Furtheron it shrinks - protected against UV light or not- the original 19mm thickness of the PE foam can't be found anywhere anymore, neither at the hot flow pipe (max. 100 degrees) or at the colder return pipe (max. 80 degrees) leading to the collectors. The average thickness is now reduced from 19mm down to 15mm, that's the average.
The same between thermal storage tank and house where the temperatures running in the pipes are only 30-60 degrees Celsius, going down to surrounding soil temperature during stagnation. The entire installation is since about 3 years in place.

Not only in thickness it shrinks but also in length.

And the material was certified by the manufacturer for the purpose, but after 2 years the guarantee doesn't count anymore. And 2 years was the maximum I got out of it. At the hotter places (max.100 degrees Celsius) not even that.

The OP plans a boiler based heating system, so the temperatures to which the piping is exposed will be much lower than 100 degrees Celsius.
But that should be calculated: the higher the temperature chosen the faster the synthetic foam will deterioate. And who want's to dig-up this trench in a couple of years again....

Sparkpea

Thanks heinbloed for the information