drain heaters

[jamcool]

Have a question guys, but first let me say how informative these forums have been to me,now to my question.
On walk-in-freezers that pull down to about 5 degree F i have noticed that the heater drain comes on when ever the unit goes into defrost which to me seem to make sense,well went to a site and saw a fellow technician wire a drain heater to the evap. fan power,so now the heater stays on as long as the fans run but then off when the unit goes into defrost,a long question but can or should it be done like that.

[rbartlett]

i have seen it done /done it
wired to evap fans
wired to defrost heaters
wired permenantly

to a certain extent it depends on the wattage of the tape. those low watt self regulating should be on all or most of the time -ie perm/evap fans

the high watt ones will heat up quickly and hence usually wired to defrost heaters. if left on they don't cause too much problem except if the drain is insulated after fitting then it will over heat
and burn out.

cheers

richard

[Andy W]

R Bartlett you are absolutely spot on, I prefer to use a self regulating tape permantly on, supplied by its own fuse or wired with the door heater/lights, also you have the choice of internal or external drain heater, external are always easier to replace, internal are more difficult to replace on panel coolers, I hate blocked drain and iced up evaporators by the way.

[jamcool]

Thanks ,just a few points after chatting with the tech. i found out that the original installation had the heater wired through the defrost but the copper elbow kept bursting a 90 degree elbow,dont remember the wattage on the heater tape but wouldnt say a 45 degree elbow an not a 90 a better choice?easer water run off ,just getting things clear for future reference?

[rbartlett]

Thanks ,just a few points after chatting with the tech. i found out that the original installation had the heater wired through the defrost but the copper elbow kept bursting a 90 degree elbow,dont remember the wattage on the heater tape but wouldnt say a 45 degree elbow an not a 90 a better choice?easer water run off ,just getting things clear for future reference?

what is happening is that water is collecting in the elbow and not running away properly. (I suspect if you look closely you will see that the angle is wrong..)

as the heater only comes on every 6 hours it has the intervening time to freeze. -which it does of course, expands and splits the elbow.

90 or 45 or any pipe will suffer the same fate due to this happening. sort the piping and the problem will go away..


cheers

richard

[Krups]

what is happening is that water is collecting in the elbow and not running away properly. (I suspect if you look closely you will see that the angle is wrong..)

as the heater only comes on every 6 hours it has the intervening time to freeze. -which it does of course, expands and splits the elbow.

90 or 45 or any pipe will suffer the same fate due to this happening. sort the piping and the problem will go away..


cheers

richard

hi, so what exactly would the procedure be to sort the piping out ?
make sure its on a slope so gravity pulls the water away before having a chance to freeze up?


cheers

[Temprite]

make sure that the trap (if it has one fitted is) outside the room.

[87mustang]

Drains as mentioned should have a 4 inch drop per foot of pipe and 45 elbows are usually used for that water's rapid escape.
Drain heaters should always be on. Good service/install procedure to be able to always verify operation.
Self regulating will come on as the pipe gets colder starting at abot 42 degrees.