Ask Caleffi
Ask Caleffi
#25 Why use radiant heating & cooling? (with Max Rohr)
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Max Rohr, "a long-time listener and first-time caller," joins Greg and Dan during this Episode of the Ask Caleffi podcast. Max shares his well-earned experience with radiant heating and cooling systems, placing a magnifying glass on PEX. He discusses radiant heat sources, the benefits and versatility of these systems, and then dives into PEX variants. Greg and Dan chime in to talk about maintenance, system protection, and tips.
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00:02
[Music]
00:05
welcome to ask Caleffi the podcast that
00:08
dives into real life problems that
00:10
plumbing and hvac technicians face in
00:12
the field we're your hosts from the
00:14
caleffi tech support team i'm greg tubbs
00:17
and i'm dan ferkus welcome we look
00:19
forward to sharing some stories from our
00:21
tech calls and using our background and
00:23
expertise to make your days a little
00:25
easier
00:28
[Music]
00:30
hey there welcome back uh another
00:32
episode of the ask caleffi podcast how
00:35
you doing dan i'm doing good yeah
00:37
welcome back everybody thanks for coming
00:38
back
00:39
today we got a special guest one of our
00:42
education and training managers mr max
00:45
rohr
00:48
max how are we doing today hey max i'm
00:50
doing great one time uh long time
00:52
listener first time caller so i'm gonna
00:55
show you guys right yeah we're excited
00:57
to have you here today tell us a little
00:58
bit about yourself i mean obviously
01:00
you're a pretty smart guy you're one of
01:02
our one of our training guys here at
01:05
caleffi north america but
01:07
give us a little background on on your
01:09
career in this industry sure yeah so i
01:12
uh i've been trying radiant uh type two
01:17
to measure rebar uh since i was like
01:20
seven or ten years old or something like
01:22
that with my family business working
01:25
with my dad so i would have my uh
01:27
buddies come with me in for probably
01:29
yeah ten dollars for the day we'd snip
01:31
all the zip ties uh and pick up all the
01:34
pieces and get it ready for the concrete
01:36
pour so i've been around the
01:38
radiant pipe for a long time than have
01:40
since worked
01:41
in the wholesale and rep and pex
01:45
manufacturer levels for real most
01:47
recently for about five years so kind of
01:50
seen the
01:51
radiant industry from a bunch of
01:53
different angles and really love it
01:56
yeah it's exciting well we're happy to
01:57
have you here today we got a big topic
01:59
today we're going to talk about pax so
02:01
we're excited to have you here to talk
02:03
with us about that
02:05
yeah thanks for having me yeah i mean we
02:06
make pretty wide range of products that
02:09
work with different types of pecs and
02:11
yeah a lot of different fittings to
02:13
attach to it right and we get plenty of
02:15
questions about you know will it work
02:16
with this or will it work with that
02:19
and
02:20
from from the
02:21
from the product aspect of it but then
02:23
we also get plenty of design questions
02:25
too so
02:26
uh we got a few bullet points we're
02:28
gonna we're gonna tackle with you today
02:31
yeah we actually do get a lot of
02:32
questions about application and you know
02:34
we don't really design systems but you
02:37
know
02:38
you myself and max we all have a
02:39
background of you installing and
02:42
and working with pax and radiant systems
02:45
so you know we help a little bit we
02:47
don't we don't design the full system
02:49
yeah first things that we want to talk
02:51
about is just you know
02:53
why use radiant heat
02:57
yeah i love radiant because it's one of
02:59
those few things in life that
03:02
when done well is a great mix of comfort
03:04
and energy efficiency so
03:07
you get both at the same time you can
03:09
hide it in the floors the ceilings the
03:11
walls
03:12
you can use all sorts of different heat
03:14
sources so it's kind of future proof in
03:16
a sense that you could use a
03:18
non-condensing boiler with uh you know a
03:20
boiler protect valve condensing boiler
03:23
air-to-water heat pump over the course
03:24
of the life of the system
03:26
and the big picture is about 30 energy
03:29
savings compared to forced air when it
03:31
falls well so i think those are some of
03:33
my favorite things about about radiant
03:35
as a general way to heat or even cool a
03:38
space yeah it's really versatile with
03:40
the design i mean you can you can size
03:42
your piping and spacing in an
03:44
application to work with some pretty low
03:46
water temperatures which really gives
03:48
you quite a gain and efficiency
03:50
yeah what the
03:52
surface area lower water temperature is
03:54
kind of the name of the game right we
03:57
even hear applications you know we
03:58
always think like radiant floor but i
04:00
hear radiant ceiling and walls i mean
04:02
i've seen it put in shower walls i mean
04:05
there's really it's really a versatile
04:06
application
04:08
yep corner corner unit of a multi-story
04:11
building with radiant if it's all glass
04:13
you know below the windows can be a nice
04:16
way to go just that really cold part of
04:19
a
04:20
building or a house or something like
04:22
that you can you can hide it anywhere
04:24
yeah it's really nice that you can you
04:26
basically make it invisible in the home
04:28
home or or office space
04:31
absolutely
04:33
well i'm
04:34
in-floor heating's been out for a long
04:36
time
04:37
you know i mean i've worked on systems
04:39
old frank lloyd wright homes that have
04:41
steel piping in the floor no steel or
04:43
copper yeah and my house in particular
04:46
has uh copper in the ceiling
04:49
so yeah that's been i abandoned that i
04:52
don't even use it because i'm afraid of
04:54
the sprinkler system that might right
04:57
at some point will or could
05:00
yeah yeah and that's uh so there were a
05:02
lot of cool systems with metallic pipes
05:04
uh concrete is not
05:06
friendly to the metallic option so
05:08
that's why a lot of those systems have
05:10
failed then that's why they've uh
05:12
switched the tech because uh pex is
05:15
pretty uh pretty indifferent to the
05:17
chemicals in the concrete so it makes
05:20
for a much longer life span inside of
05:22
the embedded in concrete it's very happy
05:25
so you guys want me to kind of cover the
05:28
the difference between the the pex uh
05:31
variants that are on the market right
05:32
now yeah i think we should talk about
05:34
that we should think maybe people don't
05:36
understand the different types of pecs
05:38
that are out there
05:40
sure so uh pecs in general uh
05:43
polyethylene cross length is what we're
05:45
talking about and it's abbreviated to
05:46
text so if you take like a red solo cup
05:50
um that you'd get at a barbecue or
05:52
something like that you can rip it like
05:54
a piece of paper you can rip it from you
05:56
know where you would take a drink all
05:58
the way to the base and it rips straight
05:59
down it's polyethylene but it's not
06:01
cross-linked
06:03
so with text you cross-link it it ends
06:05
up more like at the molecular level like
06:08
a chain-link fence or a spider web so
06:10
you can't really rip uh pecs in any
06:13
direction it doesn't have parallel
06:15
molecules they're all kind of woven
06:17
together that makes it strong and
06:19
flexible and then as far as the
06:22
standards go if it's listed to aspm f876
06:26
it's gonna work for radiant
06:28
installations and it's gonna have all
06:29
the performance characteristics that you
06:32
need for that type of installation
06:34
so then it breaks into three different
06:37
camps and depending on where you live or
06:40
what you've installed you may have you
06:42
know blood rivalry with these different
06:44
types of texts but i'll just kind of
06:46
describe the difference between
06:48
a b and c how they're produced and kind
06:51
of uh where you go from there but again
06:54
support is going to be the deciding
06:56
factor between these different companies
06:58
and different types of techs that's
07:00
really what you should shop for uh all
07:02
aspm f876 lifted pipe lifted pipes
07:06
they're gonna hold water they're gonna
07:07
meet performance standards by an inch or
07:09
by mile but they're gonna cover what you
07:12
need to do for radiant heating so
07:15
pex a or the engel
07:18
or peroxide method so picture a pasta
07:21
maker since we're an italian company so
07:23
you've got you know a big pile of dough
07:25
then you squeeze it through a specific
07:28
shape so it's going to come out like a
07:30
you know like goes from raw ingredients
07:32
that it blends in the extruder and it's
07:35
going to come out the like a play-doh
07:37
maker as well the shape of the the pipe
07:40
so with the pex a
07:42
the polyethylene is actually
07:43
cross-linked right at the edge of the
07:46
pasta maker so right as it's coming out
07:48
into the initial shape it's cross-linked
07:50
right then so some advantages there is
07:52
that with the pecsa you can repair a
07:54
kink with heat so if you do bend it
07:57
during the installation
07:58
it always kind of wants to go back to
08:00
that initial shape and the pex they lets
08:02
you heat it and it kind of relaxes the
08:04
kink right out of it yeah that's another
08:06
thing that you can
08:07
as i say the pex a always seems to have
08:09
quite a memory in in the pipe i've i've
08:11
noticed that i've kinked a pecs a pipe
08:13
before and i've used a heat gun to heat
08:15
it up and and it would regain its
08:17
original shape
08:19
yeah it wants to come back to that uh
08:21
that kind of origin story
08:24
shape the marble origin story round it
08:26
wants to get back to that so
08:28
the other reason that that's important
08:30
is that you can use it with cold
08:31
expansion fittings so the pecs a pipes
08:34
you can expand them over the barb of a
08:37
f-1960
08:39
or a compression sleeve style fitting
08:42
you can expand that up and over and then
08:44
the memory of the pipe brings it back
08:46
down the seal over the barb
08:48
so
08:49
really flexible best flexibility of the
08:51
group of a b and c
08:53
and always wants to come back to that
08:54
shape so those are some of the
08:56
properties that you use to your
08:57
advantage if you're going to install a
08:59
pex a
09:01
right so
09:02
then we'll move to pex b so this is
09:04
called the moisture cure or thyleen
09:07
method so after the polyethylene is
09:09
extruded into the shapes of the size of
09:12
whatever pipe you're going to make
09:14
then you coil it and you cross link it
09:17
in coils in like a steam sauna basically
09:20
so there's no tanker pair with this type
09:23
of uh this type of pipe with a b you're
09:26
gonna want to cut out any sort of kink
09:28
and put in a fitting or a little
09:29
coupling there to uh fix the
09:32
kink if you get one
09:34
but it is a little bit more rigid than
09:36
an a and that can be you know that could
09:38
be good because
09:39
if you're trying to hold a higher
09:40
pressure i mean anything in a plumbing
09:43
uh and heating situation you're not
09:45
getting anywhere near the performance
09:47
capabilities of these types they're all
09:49
well overqualified for what you do for
09:51
just a radiant system um but
09:54
maybe a little bit less expensive than
09:56
an a2 and is still going to be able to
09:58
install easily to make the bends that
10:00
you would need for a radiant system
10:04
right
10:06
as well
10:07
yeah one of the things that you'll
10:08
notice is that uh if you're gonna
10:10
install a b
10:12
it likes to bend tighter in the
10:14
direction that it was coiled so if you
10:17
take a b and you try and bend it
10:18
completely
10:19
i guess like against the grain
10:21
it doesn't like to do that as much so
10:23
give it like a little 180 twist and it's
10:26
going to want to bend a little bit
10:27
tighter the way that it would coil
10:29
okay
10:30
and then the the last one the pec c
10:35
so this is also called like the
10:36
radiation method so after the
10:38
polyethylene is extruded
10:41
you almost microwave it in sense so you
10:43
put it in coils into like an
10:46
oven kind of and then you're going to
10:49
facilitate the cross-linking like that
10:51
so both a b and a c are gonna be after
10:54
the fact that you're making the cross
10:56
linking uh where the a is right at the
10:58
extruder so those are kind of uh
11:01
you could get a full eight hours out of
11:05
any of your pex people on why a b or c
11:08
is better
11:10
and they're they're all going to work
11:12
well for for radiant heat so again it's
11:14
kind of support it's where i would lean
11:16
if you're trying to decide between one
11:18
or the other
11:19
yeah i've i've in the in the past i've
11:22
always worked more with the pex a
11:23
product and and i like that because i
11:26
always use the expansion fittings and
11:28
you know if you ever run the risk of
11:30
kinking it especially you know laying
11:32
tubing down in the floor and you get a
11:33
kink you're not subject to have to put a
11:36
coupling and you can heat that up and
11:37
get that to go back to its original form
11:40
so that that's what i always liked about
11:42
the pex a
11:44
yeah and uh yeah it makes for an easy
11:47
day um with the with the kalefi
11:50
components that we actually have tail
11:51
pieces with our different products for
11:53
either
11:54
expansion for a pex a uh for a f-1960
11:58
type sitting or for a crimp fitting that
12:00
will work with an abrc so we've got
12:03
tailpieces that you can go from any of
12:05
those to our products which which makes
12:06
it helpful yeah that is nice especially
12:09
when you get to the manifold that
12:10
transition to the manifold it's not
12:12
going to matter what type of pecs you
12:13
have we have a great fitting to
12:15
to adapt there certainly yeah yeah you
12:18
could even mix and match if you wanted
12:19
to wouldn't recommend it but you could
12:24
oh and i know one of the one of the big
12:25
requirements with a radiant system is
12:28
you know having that oxygen barrier
12:30
yeah so that's a big deal
12:32
and that's something that came up in the
12:34
polybutylene days for people that have
12:36
been doing radiant for a long time is
12:38
that they had this flexible
12:40
plastic that made
12:42
radiant installs easy
12:44
but it didn't have an oxygen barrier and
12:46
then what people noticed is that
12:48
months and years later they were just
12:50
running through uh ferrous components in
12:54
the system so this is going to be your
12:55
expansion tank is the thinnest steel uh
12:58
or a cast iron
13:01
of a pump they were just really gummy
13:02
and they would they're basically rusting
13:04
from the inside out it's because oxygen
13:06
will continue to enter through the pipe
13:09
you know it doesn't leak and then it
13:11
continues to rust your components you
13:13
want kind of a tight drum inside of your
13:16
radiant system and until we figured that
13:18
oxygen barrier out we weren't accounting
13:21
for that but now there are rules about
13:23
it there's a din
13:26
4726 standard that basically is a global
13:29
standard that sets the limit for how
13:31
much oxygen can come through the pecs
13:34
and what they do
13:36
to protect the oxygen from coming
13:39
through is they put like an additional
13:40
jacket that's called a co-extrusion
13:42
right over the pecs that's specifically
13:44
designed to keep the air from
13:46
you know coming through the wall of the
13:48
text and that is important because then
13:51
your other components aren't rusting
13:53
away for colefi products it's not really
13:56
an issue it's also not an issue for
13:58
the pipe because we're making stuff out
14:00
of brass or plastic
14:02
rubber and then the pipe itself doesn't
14:05
rust there's nothing ferrous in the pipe
14:08
it just uh it manifests in your your
14:11
other metallic
14:12
components or your heat exchanger of
14:14
your boiler which is definitely not
14:17
where you want to have uh big globs of
14:20
uh rusty debris right yeah you'll see
14:22
that a lot with your cast iron pumps or
14:24
if it's put in with a cast iron boiler
14:26
four hydraulic separators that are
14:28
hooked yeah expansion tanks that was one
14:30
of my first
14:32
calls when i got here
14:34
was a contractor had some 902 barrier
14:36
packs he had no idea what he had
14:39
right but he called pretty pretty upset
14:42
that you know hey this thing we just put
14:44
it in not that long ago it might have
14:46
been six months beforehand
14:48
it's pinhole leaking what are you gonna
14:50
do for me why is it rusting out
14:53
well you know one thing leads to another
14:55
and you're trying to talk to them and
14:56
you find out that it's some really old
14:58
pecs that's 902 barrier right and
15:02
you know the only thing you can
15:03
recommend at that point is hey you need
15:05
to put a heat exchanger to separate that
15:07
part of the system away from
15:10
the primary yeah exactly that's the
15:13
that's the best recommendation it's just
15:14
to separate it completely and then you
15:16
protect the rest of your new expensive
15:18
components yeah i'd usually see that
15:21
when you had a homeowner that came in
15:22
and put their own packs down and they
15:24
looked at the price of packs and
15:25
realized that you know boy i'm going to
15:27
pay x amount for something with an
15:29
oxygen barrier and for you know a
15:32
quarter or third of the cost i can get
15:33
this other pecs and why can't i just put
15:35
that in and sure well then it ends up
15:37
costing them a lot in the end yeah a lot
15:40
in service calls and
15:41
replacement parts right
15:43
yeah system re-pipes to try to separate
15:46
it
15:47
and one of the things i always stress
15:48
with tax too is that if there's
15:50
something that you would spend a little
15:52
bit more on it should probably be this
15:53
thing that you bury in concrete
15:55
you might
15:56
if you wanted to save a couple dollars
15:58
on an expansion tank uh or you know even
16:02
a pump or something like that you can
16:03
replace those you might even have
16:05
isolation valves or whatever you're not
16:07
going to want to chip up the concrete
16:09
and put new pex in it's it's basically
16:11
going to be the type of system that
16:13
people abandon so it's worth spending
16:15
the money up front to design and install
16:17
it well yeah it sure is yeah pex is
16:20
definitely more of a permanent component
16:22
of the system
16:23
yeah and when you pick a good quality
16:25
packs and installed right i mean it's
16:26
going to be there it's going to last a
16:28
long time it's going to perform well for
16:29
you
16:31
i mean in most cases it's going to
16:32
outlive the house
16:35
yeah it sure is
16:37
at least in north america where we
16:39
change houses so frequently right
16:42
yeah but you know 30 30 plus years is
16:45
not unrealistic for pecs especially when
16:47
it's buried in concrete right right yeah
16:50
it's a solid product how would you go
16:52
about protecting pecs
16:54
say from sun and other damage
16:58
so
16:58
generally speaking
17:00
the sun hates plastic or plastic hates
17:03
the sun i'm not sure
17:05
which one or both absolutely and maybe
17:08
yeah the uv
17:09
and a good way to you know see this in
17:12
in real time is if you you guys are
17:14
around fishing both if you see a boat
17:16
that's just been out in the sun or in
17:18
the water forever
17:21
the sun just eats it away and makes the
17:23
the plastic brittle and things like that
17:25
so
17:26
best case scenario with anything plastic
17:28
is to keep it out of the sun unless it's
17:30
specifically designed to be in the sun
17:32
so with the oxygen barrier pipe you want
17:35
to install that and then pour the
17:37
concrete over it as soon as you can
17:40
specific pex manufacturers will give you
17:42
an answer in a number of days and
17:44
they'll say okay you need to keep this
17:46
out of the sun
17:48
you can't have it in the sun for more
17:50
than 90 days or something like that as
17:51
an example the reason you wouldn't want
17:53
to do that anyways because if you're
17:55
going to install a radiant system
17:57
and just leave it uncovered for 100 days
18:00
somebody's going to put a nail through
18:02
that or step on it or drive a truck over
18:04
it over a sharp edge and you're going to
18:06
have a leak somewhere so the sooner you
18:08
can put it down and cover it up with
18:10
concrete the better uh just so you're
18:12
not tracking down leaks when it comes
18:15
time to uh for the concrete but uh what
18:18
will happen with the sun is it breaks
18:19
down the pipe and makes it brittle over
18:21
time um
18:23
and that's just not anything that we
18:25
want so what you want to do another
18:27
thing to protect the pipe is if you're
18:29
transitioning out of the concrete so
18:30
maybe this is right under the manifold
18:33
or across an expansion joint or
18:35
something like that you want to put
18:36
either a bend guide like a pvc bend
18:39
guide
18:40
or corrugated sleeving between the
18:42
expansion joint
18:44
so there's not a little friction point
18:46
with the plastic so coming out of the
18:48
slab there can be a sharp concrete edge
18:51
you want to make sure that as the pipe
18:52
heats up and cools down it's not just
18:54
wearing on a sharp concrete edge so
18:56
that's where those bend guides are
18:57
important
18:58
to make sure you take away that wear
19:00
point that you're setting yourself up
19:02
for success there so
19:05
that's a definitely best practice
19:07
yeah i always like to try to get in as
19:09
close to the concrete being poured as
19:11
possible try to get in the day before
19:13
knowing the masons were coming in the
19:14
morning to pour that concrete but boy
19:17
you think of you know the cost to
19:19
replace that pack should something go
19:21
wrong you always want to take steps to
19:23
protect it right
19:25
yeah it's uh if if you
19:28
trusted yourself enough and we're fast
19:30
enough you just start putting the pipe
19:32
down as soon as the concrete truck is
19:34
pulling up the driveway
19:39
yeah
19:40
yeah
19:41
well and then from there you got to
19:42
pressure test it i would imagine you
19:44
know that's that's the next step yeah so
19:47
a couple
19:48
a couple tips for that if you're going
19:50
to pressure test
19:53
a lot of people use air only
19:55
and the reason that they would do that
19:56
is they'll use compressed air because if
19:59
you're in any sort of climate that it
20:01
could freeze
20:02
you don't want the water to freeze in
20:04
your pec before you pour the slab you
20:07
want to have antifreeze in that if
20:08
there's any sort of
20:10
potential
20:11
for it to freeze so air is a good way to
20:12
go if you don't know when the boiler is
20:14
going to be installed and you know
20:15
you've got to walk lead time there
20:17
one of the things i recommend is just
20:19
you don't need to you don't need to set
20:20
any records with that so usually pex
20:23
companies are going to give you a
20:24
recommendation for the psi you need and
20:27
it's probably going to be 120 psi or
20:29
less i've heard some stories of people
20:31
you know bumping it up to 400 pfi just
20:33
to set it or whatever
20:35
is not helpful and it's dangerous as
20:37
well so if somebody dropped the hammer
20:39
on a polymer fitting or something like
20:41
that you could have a pretty rapid
20:44
amount of air coming out of a very small
20:46
orifice
20:48
which is very loud and very dangerous
20:51
they're just gonna you know fill up the
20:53
the advantages you'll know if you have
20:56
somebody else at the job site put the
20:57
nail through
20:59
a piece of pipe that's under pressure
21:01
you definitely don't want that to happen
21:02
but you're gonna have uh you're gonna
21:04
have a pretty big amount of dust and
21:06
whatever room that was
21:08
as all the air comes out of that whole
21:09
field so yeah do you ever have to worry
21:11
about you know
21:13
using compressed air for for pressure
21:15
testing you know with the temperature
21:17
changes and the expansion you know
21:19
i mean pecs when the temperature changes
21:21
i've seen it expand i mean it'll yeah do
21:24
you ever have to change
21:27
it it can give you a false uh you know
21:30
false positives that you have a leak in
21:32
some cases if you installed the pipe and
21:34
pressurized it when it was 40 degrees
21:36
outside and then you come back when it's
21:38
you know 80 degrees the next day
21:41
it's going to change shape a little bit
21:43
sometimes
21:44
in extreme cases it can even buff out of
21:47
a few fasteners and things like that um
21:50
it can almost give you like an ion it
21:52
can almost give you like a false
21:54
impression of a leak too isn't it
21:55
because won't the pressure change as it
21:57
expands
21:59
yeah and um
22:01
one of the things that you know the text
22:03
itself if they're let's say you took the
22:05
pex to a thousand pfi or something like
22:07
that uh usually the the pex is gonna
22:10
fail in what's called like a ductile
22:12
mode so it's just going to come out of
22:14
the side of the text but it doesn't
22:15
throw any debris or anything like that
22:18
but if you were to
22:20
drop a hammer or a brick on a polymer
22:23
elbow or something like that that's when
22:25
pieces of that chunk of that can fly
22:27
everywhere so some people will uh do a
22:30
pressure test with water or a mixture of
22:32
air and water you don't need as much air
22:34
so it's mostly filled with water
22:37
but again the downside is that it can
22:38
freeze um
22:40
right yeah you want to know you want to
22:42
know what the weather is going to be so
22:43
you can protect that packs
22:45
yeah
22:48
well i think we covered the basics of
22:50
packs pretty well
22:52
what it is and the types of pecs yeah so
22:55
we're gonna pick this up on a part two
22:56
episode
23:00
stay tuned for that yeah thanks max
23:02
thank you i mean i get to be a return
23:04
guest yeah we're gonna let you come
23:09
as always thanks for uh thanks for
23:11
tuning in yeah thanks guys thank you for
23:13
tuning in if you ever need help please
23:16
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23:17
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23:20
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23:23
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23:29
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