Outdoor Wood Furnace Info

All-Purpose OWF Discussions => General Outdoor Furnace Discussion => Topic started by: mgw44 on September 06, 2011, 10:21:53 AM

Title: Trench Depth?
Post by: mgw44 on September 06, 2011, 10:21:53 AM

So, the new boiler is being delivered September 16.  I had a 65' trench to dig and broke ground three weeks ago.  Due to time, rocks, and clay I was only able to dig about 10' in three weeks.  So, I rented a really nice Kubota mini-excavator this weekend.  Needless to say, I had a great weekend. 

I have the trench at about 45" deep which got me down past the clay into nice moist sand. 

Now for the questions:  At what depth would you recommend I lay the insulated Pex?  I see it should be at a minimum of 26" based on my installation manual.  Is there a benefit to going deeper?  Are there any negatives to going deeper than 26"?

mgw44

Title: Re: Trench Depth?
Post by: RSI on September 06, 2011, 10:28:04 AM

The only reason not to go deeper is if you get into ground water. Clay is pretty conductive so if the sand just damp and not really wet then I would try to get it that low. If your trench starts getting water in the bottom (not from rain) then go shallower.

Title: Re: Trench Depth?
Post by: mgw44 on September 08, 2011, 03:41:12 PM

Thank you for the second opinion.  The sand is nice.  mostly sand and small stones no bigger than a marble.  Not a hint of standing water anywhere with very good drainage.

Title: Re: Trench Depth?
Post by: gmviso on September 13, 2011, 04:05:23 PM

So, I bit the bullet and bought thermopex. CB and my local CB dealer both say 8-12" is deep enough.

Title: Re: Trench Depth?
Post by: martyinmi on September 13, 2011, 04:27:38 PM

Quote from: gmviso on September 13, 2011, 04:05:23 PM

So, I bit the bullet and bought thermopex. CB and my local CB dealer both say 8-12" is deep enough.

When I buried mine 5 years ago, they (CB and CB dealer) said 18", except for under driveway, where I went 24". I think CB still recommends 18"-24".

Title: Re: Trench Depth?
Post by: mikenc on September 13, 2011, 07:05:13 PM

I Would go below frost line.

Title: Re: Trench Depth?
Post by: tulenutn2o on September 19, 2011, 06:12:05 PM

Mine is below frost line between 42-48".

Title: Re: Trench Depth?
Post by: mgw44 on September 27, 2011, 02:28:16 PM

I set mine at 40"  see pic in the Empyre thread if you would like.  the install is complete and now just waiting for cold weather.

Title: Re: Trench Depth?
Post by: tulenutn2o on September 27, 2011, 06:29:41 PM

When I dug my trench, i did hit water.I put tile in and pea gravel to make sure my pipe stays dry.

Title: Re: Trench Depth?
Post by: fireboss on September 27, 2011, 07:03:38 PM

iam in north new jersey and i went 48", frost line here is 42" i went over kill on everything !