I have an under-sink sump in my garage with the p-trap, sump bucket and
about a 1.5 feet of water in the riser above the check valve before it
goes into the house.
The pipes and bucket are ABS.
I have been paying close attention to the temps in the uninsulated
garage, and they have gotten close to 0.5C at times but no lower.
I thought about boxing it in and adding a light bulb, but I got a good
deal on 6' of heat tape.
When it arrived it stated in the instructions it is only for supply
lines. I am not sure if this is because they don't think the tape will
do the job on a larger diameter pipe, or because it could melt the pipe?
Can anyone shed some light on why they say it should only be used on
On Saturday, January 18, 2014 11:38:17 PM UTC-5, NedFlanders wrote:
Good question. I'm going looking for some myself to help a friend.
His house that is only 7 years old has one furnace in the attic.
When it got down to zero here, the condensate trap froze, water
backed up, shutting the furnace down. It also cracked the fitting,
so it's leaking into the pan under the furnace now. The condensate
trap is under the horizontal furnace and uninsulated. The idiots
who installed it put insulation on the drain pipe that runs 15 ft in
the attic, but none around the approximately 5x7 plastic condensate
Looking at the Lenox install instructions, they say that any install
where the temps can drop below freezing, the plastic condensate trap
and the drain line should be wrapped with heating tape. So, apparently
there has to be tape suitable for empty drain pipe use. I'm amazed
this passed inspection.
Quick google shows there are tapes rated for plastic drain pipes:
I would suspect the issue is that there is some concern that
without water in a plastic pipe, if you wrap a lot of tape around
it, put a lot of insulation over it, it might get hot enough to
melt it. Seems unlikely to me, but in may be CYA on the part of
some manufacturers. I would be though that a lot of people are
just buying whatever is on the shelf a HD and using it like you
What am I missing here...
Are they talking about different types of tape, different types of pipe or
are they contradicting themselves? First they say "up to 8 inches in
diameter" and then they say "up to 2.5 inches in diameter".
Does the 8" spec only apply to the HVAC pipe the immediately proceeds that
Chromalox Thermwire-Wrap pipe heating tape can be applied to anywhere pipes
are subjected to below-freezing temperatures. This heat tape can be used on
plastic or metal water, wastewater or HVAC pipes up to 8 inches in
diameter. The Pre-assembled Thermwire-Wrap has an attached cord and plug
for simple and quick installation. It can be used on pipes up to 2.5 inches
in diameter, including outdoor spigots, and is ready for use up to 50 feet
On Sunday, January 19, 2014 9:53:42 AM UTC-5, email@example.com wrote:
I think I may have cracked the code here. The typical heat tape
products I've found that are stocked at retailers are all controlled
only be a thermostat. There is also "self-regulating" tape, where
it looks like it has essentially power wires down the cable and
some kind of heat sensitive resistive material between that
regulates the temp along the entire line. From reading the description
of those, they say for use on metal or plastic pipe and do not
say it has to be filled with water.
Easy heat psr
I would bet that if you applied the typical tape to ABS, you'd be
fine as along as you don't do something dumb, like overwrap it. I
can't believe with all the condensate and similar drain pipes that
folks are doing research and actually reading the specs. Must
be millions of ABS waste pipes and similar wrapped in the off the
shelf stuff from HD.
On 1/19/2014 9:53 AM, firstname.lastname@example.org wrote:
I wouldn't be amazed. I've seen a whole house full of stuff that
shouldn't have passed inspection, but did twice. Once by the code
inspector and once by a 'professional' house inspector that was supposed
to be very good. Apparently, good has a broad meaning with lots of
The sump is above ground under the sink, it is vented through my home's
drainage venting so removing the p-trap is probably out of the question.
I had thought about using a cheater vent and since the riser will always
have water in it there should not be any problems with gasses? but, that
is only 1/2 of the area that could possibly freeze.
It's not like it would be disaster if it did freeze and leak as it is in
the garage and there is no wood or dry wall to get wet... The riser is
is about 9' so the amount of water would be limited as well.
Conductivity probably. If you wrap a liquid filled pipe with a loop of
tape every X inches, the fluid inside will conduct the heat and warm it
fairly evenly. With a large diameter pipe with little or no liquid,
spots will be warm, but you can get icing between.
If your sump is filled with water, it should work OK as long as it is
permitted on plastic pipe..
I think I will throw the side of the wire with the heat sensor into my
deep freezer and see how hot this wire gets. I have no plan on wrapping
it as we are only talking maybe a max of -2 deg so even just a small
amount of heat would do the trick.
I'd be reluctant to rely on insulation alone. Insulation will simply
slow the rate of heat loss or heat gain.
I'm wondering if he couldn't simply position an electric heater with a
fan in it in front of that piping to keep it toasty warm at night. I'm
sure that would cost more than wraping the pipe with heating cable, but
it's only for the few nights this winter that threaten to cause the
water in the trap to freeze. It's not going to make a great big
difference on his electric bill.
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