Crank case heater

[anthonyac1]

On a Copland scroll usually has those hose clamp looking style crankcase heaters around the bottom portion area of the compressor, it has a constant 208/230 volts applied to it. I amped it out it's drawing no amps, I ohmed it out it was open, need to replace it, I amped out 3 others heaters same result, do they have some kind of ptcr piece in it, once it heats up to a certain temp, resistance increases doesn't allow power to flow through???? But then when ohming it out I should get a reading! Its a cch usually straight forward but being that I seen like 4 that were bad doesn't seem right,

[ammoniadog]

I believe the most common type that I think you are describing get hot all of the time (not self regulating). They don't draw a lot of power, though. Usually it is less than an amp, if I remember correctly.

[Core_d]

I know some run constantly and some have a temp controled shut off . Im not sure the means of witch they shut off i would cool them down and test them to make sure. Shouldnt take that long

[Core_d]

Plz post back when you get to the bottom of this. Solid state relays that act similar to what your descriding come with ohm/temp charts. As well as cad cells. Im all ears

[trippintl0]

Did you check resistance and amp draw on the new heater? Because I once had a Fluke meter that wouldn't read ohms above a certain point, and I condemned all kinds of stuff before I figured it out... Amp draw will be so low you may not pick it up. I think the best test is to just see if its hot?

[ryan1088]

The ones I've seen draw between .5 and 1 amp. We must have changed 50 of them last spring/summer. I don't think they are incredibly reliable.

[steve wright]

Most of those heaters I've seen about 70 watts (with comp # we can find out exactly) with 230V that wold be about 0.3 amps. Hard to read.

To get more accurate reading you can loop wire five times in jaws of your amp meter then divide you reading by five for actual amps.

Make sure heater is energized sometimes heater is locked out when comp running

[anthonyac1]

i looked it up once i got home from work it is a 70 watt heater if you divide that by the incomming voltage 207 volts = .33 amps pretty much what you have stated. i emailed copeland tech support model and serial info but no response on any info. the heater did feel warm but with no amp draw nor any ohm reading was throwing me off. in this situation the heater runs continuous wired to the line side of contactor straight.

[anthonyac1]

Plz post back when you get to the bottom of this. Solid state relays that act similar to what your descriding come with ohm/temp charts. As well as cad cells. Im all ears

i emailed copeland tech support but they never replied back with info. once i get an answer ill reply back. but for now ill say the heater is still good. it was warm not hot, has me iffy plus no ohms and no amps.............. maybe the amps were to low to pick up, but ill keep looking into this for future reference.

[Core_d]

Thanks for the up date. After reading the posts ide say your meters not sensitive enough or more likley its heated its last case. If some cch did come with a thermistor type shut off someone would have posted it by now. Let me know

[steve wright]

If you google copeland AE 4-1312 then go the list of CCH for described scroll comp.

They are heater wire not solid state in this range size.

You might be waiting a while for them to get back. Holidays and all

If that is wrong size range comp shoot me back I have the data at office for all of them.

[Capz]

Using ohms law, if you have 208v (E) & .33amps (I), resistance (R) would be 630ohms. I wouldn't depend on a clamp on amp meter to accurately read .33amps but having said this, your clamp on may show something and if resistance is near 600ohms, it should be working. Watts = E*I, or in this case 68 watts

[coldjoe]

I have come across this alot also.they seem to suffer on compressors with a sweatback to the suction with the water running down onto one spot on the heater

[Core_d]

Using ohms law, if you have 208v (E) & .33amps (I), resistance (R) would be 630ohms. I wouldn't depend on a clamp on amp meter to accurately read .33amps but having said this, your clamp on may show something and if resistance is near 600ohms, it should be working. Watts = E*I, or in this case 68 watts

Ohms law doesnt add up with alternating current. Not your basic triangle chart anyways lot of other factors peak voltage ect.

[steve wright]

It does for resistive loads the CCH is resistive.

You are right that it will not work with capacitive or inductive loads.

[Core_d]

It does for resistive loads the CCH is resistive.

You are right that it will not work with capacitive or inductive loads.

Yea your right i just tested this with my oven😊 worked like a charm. I do remember messing with this in school with light bulbs and it wouldnt add up. I believe we came to the conclusion bulbs did not actually pull the wats they were rated for. Thanks for the correction

[smilies]

Yea your right i just tested this with my oven�� worked like a charm. I do remember messing with this in school with light bulbs and it wouldnt add up. I believe we came to the conclusion bulbs did not actually pull the wats they were rated for. Thanks for the correction

Incandescent bulbs are also resistive loads. They are heaters.

[steve wright]

Hey I'm at 41 years and the only thing I know for sure is the more I learn the more there is to learn.

In the field there are many things like instrument error that can make not add up.



Keep going after it.