10’ riser; inside route w/ 5 couplings, or outside route w/ no couplings

JShep

Our house has an enclosed sun porch, half is over a room below, half is over open air.  There is plenty of room to run (and I have already done so) a 2’ extension off the end of our steam and condensate mains through the cavernous hole in the foundation where our sewer line runs through it.

The original plan was to then run risers 10’ up and into the sun porch to add a radiator.  The 3/4” steam riser was going to be wrapped in insulation and slid inside a 4” pvc pipe to protect it from cold/air/elements, and the 1/2” condensate in the same, but a 3” pipe.  That’s probably not the best insulation, but can’t be worse than the no insulation, sitting on top of cold ground dirt that pipes that used to run to the back of the house survived for 100 years.

Yesterday, I was moving an electrical in the floor of the sunroom that’s right where my pipes were going to come into the room and I bumped into a metal vent cover on the brick wall a couple feet over… looked inside.. no clue what it once did, but it’s built into the brick exterior wall of the house and runs into the basement, then dumps out in an area a few feet away from the end of my mains.  I immediately thought… well here’s where I really should run my lines.  The problem is that the brick wall is 5 bricks deep… the vent column is in the middle, and the angle I’ve got to get pipe in either from the top or bottom caps me out at about 18” of length.  So I’d have to insert a section, coupling, then another section and “build” a 6-7 piece riser inside that duct.

so that’s a very long way around asking the question;

would you run a pair of 10-12’ long risers outside the house wrapped in insulation and PVC pipe in a covered area along an exterior wall… or a pair of 10-12’ long risers out of 18” long pieces linked together with at least 5 couplings nestled within a super thick segment of the exterior wall of the building?

as much as it would pain me to undo the extensions I’ve already got running outside where the only other step I need to complete is connecting the risers up through the floor… I’m thinking the inside route is probably better.

PC7060

Running the lines outside of the house would simplify the process and allow you to properly insulate the lines. The downside is the impact to the appearance of the home. 

However, I would not run lines inside of PVC. I would approved Fiberglass insulation with a aluminum exterior cover

Steamhead

Run them inside. Even with insulation, you'll still lose a lot of heat with the outside route.

JShep

Steamhead said:

Run them inside. Even with insulation, you'll still lose a lot of heat with the outside route.

Thanks for confirming.  Plenty of cutting and threading ahead for me.

Here’s to hoping my suspicion are right that the massive delays in getting steam all the way over to this side of the house are due to the my having removed and cleaned the very large inverted bucket trap that Gordon said at his last visit “That not how those are supposed to be used,” now resulting in way too much venting right before the end of the steam main on this side of the house.  Planning to replace it with a 3/4” rad trap like the plans originally called for, which hopefully brings venting down to appropriate levels, which hopefully restores better pressure on this side and making all this pipe work I’m about to do worth it.

Steamhead

JShep said:

Thanks for confirming.  Plenty of cutting and threading ahead for me.

Here’s to hoping my suspicion are right that the massive delays in getting steam all the way over to this side of the house are due to the my having removed and cleaned the very large inverted bucket trap that Gordon said at his last visit “That not how those are supposed to be used,” now resulting in way too much venting right before the end of the steam main on this side of the house.  Planning to replace it with a 3/4” rad trap like the plans originally called for, which hopefully brings venting down to appropriate levels, which hopefully restores better pressure on this side and making all this pipe work I’m about to do worth it.

Wait till we get there. It's only gonna be a month. Refresh my memory, are we talking the long main that goes toward the back of the house?

JShep

Yea.  Long main… pushing 100’ that ends with a riser going up 5 stories.  First floor rad on that side gets nice and hot… can hear the steam up on the second floor, takes a while to make it from the first to the second floor and the second and third floor rads only get warm of the boiler is running for a while.

after I first installed the new boiler it was fine, but we had horrible water hammer due in part to ~3” of downward slope on the 2.5” main that was pooling condensed steam because the outlet to the bucket trap was completely clogged.

jacked up the pipe with a car Jack and a 4x4 (with the load spread out using a 2x8 on top of the 4x4 across two fittings), shortened the hangers so it would hold in that position.  Still had hammer going on, but then I pulled and cleaned the bucket trap… hammer went away, but seemingly so did the pressure moving the steam along because that’s when we lost heat on the 2nd and 3rd floor in the back of the house unless the cycles were long enough.

long term, I plan to shorten the main (it snakes all over which it was originally designed to do in order to feed branches that are now capped off following long ago removed radiators)… cutting about 30-40’ should help balance the front and back of the house… regardless of what the current challenge is

PC7060

Steamhead said:

Run them inside. Even with insulation, you'll still lose a lot of heat with the outside route.

@Steamhead - given the cavity is in an exterior wall would you recommend filling with blown in rock wool after the line is run?

Steamhead

As long as it can handle steam temperatures.