Insulated lines to pool, Build my own

[goosegunner]

I am going to put in the insulated lines to my pool heat exchanger this week. I have about a 45' run from the garage to pool area.

I am going to bury the pex line this week. I know most will say thermopex or equivalent but I really like the idea of pex in a 4" pvc since this is for a pool heater, from late may to early september occasional use only..

It will be 12" deep and summer use only, blown out in the fall.

Anyone had any luck with drilling holes every foot or so and spraying in canned great stuff? I would cover the holes and seams with butyl tape.

Otherwise I might just do the old bubble wrap in the PVC pipe.




gg

 

[James Gautsch]

Here's an interesting article.

http://www.builditsolar.com/Projects/SpaceHeating/SolarShed/trench.htm

 

[RobC]

The foam board idea looks good for this install but I would use the cream colored foil faced board for the layer next to the pipe. It's POLYISO. Blue and pink have heat issues at certain high temps.

Rob

 

[woodsmaster]

I plan on running lines to my pool but I'm not going to insulate. I don't mind losing a little heat in the summer, I will only use the heat occasionally for the pool and it's a 60' run. I'm going to put mine 6" deep in
elec conduit. For 45' you would be ok to use p.v.c. but it's not recommenced for long runs due to expansion and contraction.

 

[goosegunner]

I plan on running lines to my pool but I'm not going to insulate. I don't mind losing a little heat in the summer, I will only use the heat occasionally for the pool and it's a 60' run. I'm going to put mine 6" deep in
elec conduit. For 45' you would be ok to use p.v.c. but it's not recommenced for long runs due to expansion and contraction.

Expansion?

Are you saying that the PVC joints will fail after expansion of the pipe?

gg

 

[woodsmaster]

I plan on running lines to my pool but I'm not going to insulate. I don't mind losing a little heat in the summer, I will only use the heat occasionally for the pool and it's a 60' run. I'm going to put mine 6" deep in
elec conduit. For 45' you would be ok to use p.v.c. but it's not recommenced for long runs due to expansion and contraction.

Expansion?

Are you saying that the PVC joints will fail after expansion of the pipe?

gg

Yes the joints can fail from expanding and contracting and it can also cause the pipe to heave in the middle. Neither of which would be a problem in this situation though. That's why sewer pipes have a rubber seal and are not glued. At one foot deep I don't think you would get much water penetration if a joint failed.

 

[woodsmaster]

When the pipe gets hot its going to expand when it gets cold its going to contract. doing this over and over can break the seal on the joint. on a small run as yours I dont think it would be a problem. I run
120' of 3" schedule 40 pvc as a drain for a water softener and eaves trough and it heaved in the middle and didn't drain right. when I dug it up to fix it one joint had broken lose. when I fixed it I just didn't glue
the couplers and left a little room for expanshion. Didn't Know any better when I installed it. Not much fun to do the first or second time.

 

[Frozen Canuck]

Yes the joints can fail from expanding and contracting and it can also cause the pipe to heave in the middle. Neither of which would be a problem in this situation though. That's why sewer pipes have a rubber seal and are not glued. At one foot deep I don't think you would get much water penetration if a joint failed.[/quote]

Just trying to understand this here. Expansion from the heat from the pex lines or cold from the ground?

PVC pipe is used underground for septic laterals to tank.

It is also used for swimming pool plumbing. Not really sure how joint would fail if primed and glued properly?

Am I missing something?

I could use solid drain tile but I thought PVC would be more durable.

gg[/quote]




Only thing you are missing (I think) is the expansion/contraction of PVC due to the temp swings & yes in this case (glued joints) that could cause the pipe to fail underground & have you re-doing the whole thing in a year or two.

As an example think of the vinyl siding on a home it (due to the big temp swings) expands & contracts greatly over the length of each piece to say nothing of the whole wall.

Same will hold true for the pipe in the ground as it could experience a big temp swing from say 180 °F (upper limit of your boiler) to 45 °F (temp of ground when system is shut down). Huge amount of expansion/contraction to deal with in a 135 °F temp swing. The longer the run the bigger the problem.

The vinyl siding when installed correctly will slide on the wall relieving the stress, glued joints in pipe cannot & the weakest point in the run will fail.

In the case of a septic install the temp swing is much smaller say 65 °F to 45 °F, far less expansion/contraction to deal with in a 20 °F temp swing.

If you wish to use PVC be sure to use belled & gasketed joints (not glued) & dont forget to use pipe lube on the male end prior to pushing in into the gasket & keep everything clean (dry/dirty gaskets fail also).

Hope this helps.

If however I have been "clear as mud" (I can do that at times) ask me to try again.

 

[goosegunner]

Ok, it makes sense I guess. I never thought it would get that hot in the pipe. I have a 30 section of supply/return pex in my garage that is wrapped in bubble wrap. It is not warm to touch at all.

I can put it in solid drain tile. It will actually make the install easier because it has to turn. I can sleeve the tile with pvc where the gate is to protect it from foot traffic.

gg

 

[goosegunner]

I plan on running lines to my pool but I'm not going to insulate. I don't mind losing a little heat in the summer, I will only use the heat occasionally for the pool and it's a 60' run. I'm going to put mine 6" deep in
elec conduit. For 45' you would be ok to use p.v.c. but it's not recommenced for long runs due to expansion and contraction.

One thing you might want to consider is insulating lines. From what I understand the Delta T is higher when heating a pool. The return line will be cooler. Could cause more heat loss on the supply?

gg

 

[woodsmaster]

I'm sure to lose a little heat to the return side but I think it will still be hot enough to heat the pool. Maybe oversize the exchanger a little? I don't want to spend the time or money right now to do it right. I have more wood than money,so a little heat loss to the ground on occasion isn't a big deal to me. I did use thermopex for house and shop. I have to many projects going on at the moment and don't know if I'll even get to it this year. I'd like to but....... I'd be happy to just get the boiler operational before fall! I still have to build the shed it's going in, install baseboards in house, etc. All-so building a 34 x 42 x 14 tall shop after work and on weekends. No rest for the wicked.