HVAC compressor crankcase heater wiring
Вставка
- Опубліковано 1 жов 2024
- This one covers the wiring of the crankcase heater when used with the single pole contactor.
This video is part of the heating and cooling series of training videos made to accompany my websites: www.graycoolingman.com and www.grayfurnaceman.com to pass on what I have learned in many years of service and repair. If you have suggestions or comments they are welcome.
If you are a homeowner looking to repair your own appliance, understand that the voltages can be lethal, the fuels are highly flammable and high pressures are used. Know your limits.
I've disconnected every Crank heater for the last 36years here in Central Florida! 🤣🤣
Great video! Keep posting these videos!
One other thing that I think we, as techs, need to ask ourselves is
"Why are the bearings becoming washed?"
Is it because there is no CCH?
Or because the owner ran it when temps outside were 65 deg or lower?
Or because the system was over-charged (with no TXV inside)?
Or because evap coil froze up (freon leak, air flow reduced)?
Or maybe because oil isn't migrating back to the compressor quicker than it migrated out of the compressor?
Or maybe oil charge became low from it ending up being recovered along with refrigerant?
I recommend bellybands. Even if its in Miami, Florida.
Even if its just a regular condensing unit (not a heatpump).
Also, if the evap coil is above the ground level floor of the home/building (i.e. 2nd+ floors, or attic), & the outside unit is located at ground level, technicians should fashion the suction line coming off the evap coil as a "rainbow".
& make sure the system has a TXV to maintain superheat.
And outside, right before the suction line goes into the outside unit, fashion the suction line as an "inversed P-Trap".
This will decrease the chances of the compressor getting a gulp of liquid when the compressor energizes.
There's just too many engineers making something simple into something overcomplicated,Planned obselence to sell more units,with circuit boards, aluminum tubing,spine fin coils,refrigerant hopscotch,programable thermostats,furnace and condensing units are short lived almost disposable. I wish they would go back to the simple basic long lived standards, they worked fine. Today's AC companies are becoming"car salesmen"with warranties and sales gimmicks SEER ratings anything flashy to make a sale.
Jim Pettinato 👍 hey jim, you hit them where it really hurts,
I have seen them on the refrigeration systems. I think why they are dropped out on a/c and heat pump systems is the SEER and HSPF would have to be lowered if the CCR was left on.
GFM
Interesting take on that one. The heater is 50 to 100 watts. The manufacturer probably would not do it that way in most cases, although I have seen some of them done that way. I have never heard of a surge damaging a heater. Thanks for the input.
GFM
Yes, its a York champion from the middle 1980s. Yes the reversing valve has failed and I did a vid on it.
GFM
It's one of those simple, "why didn't I think of that" ideas.
GFM
IV always liked heat pumps my entire life ill be 20 next week
Why not let it run all the time, and connect leads to L1 and L2, the amount of heat isn't enough to effect operation.I'd be cautious about electrical surge by wiring it through the motor winding, I it might act like a fuse.
We are in the northwest. Glad you like it.
GFM
Thanks, you answered my question
Thanks for the support
GFM
I would live to see them.
GFM
On my 2007 Goodman heat pump, the crankcase heater is connected to L1 and L2 on the contactor, so it's always on. According to the wiring diagram, this is how it was done at the factory. This way, either a single pole or double pole contactor can be used. Perhaps some manufacturers use a thermal switch in line with the CCH to switch off the CCH once the compressor temperature is above a certain point...
All the methods you described are used with crankcase heaters.
GFM
Thanks for the quick response! Really enjoy watching your videos!
Some manufacturers will set up the CCH to be governed by 3 T/STATs.
One taking the temp of the evap coil; another taking a temp of the compressor crankcase; & another taking a temp of the outdoor temp.
The goal is to maintain a crankcase temp a certain amount above the lower of the 2 other temps (evap temp & outdoor temp).
& so, in this way, it will de-energize the CCH when the crankcase temp is warmer than the lowest of the 2 other temps (evap temp & outdoor temp).
Thanks for the support
GFM
Thanks for the support
GFM
Thanks for the thoughts.
GFM
If you swapped a single pole contactor with a 2 pole and it doesn't have a (real CCH) just uses the winding as some units do tp act as a heater does it have to have constant power to the windings as a real CCH does during none operation state. or do I not need it that way
Thanks for the support
GFM
I have a Carreir unit that was installed in 2008. It has a CCH wired just like this except one of the legs of the heater goes to a control board and shares the same blade as the black fan wire. There is an inline thermal switch that I assume controls when the CCH turns on/off. The issue I'm having is that some how, there is a small amount of voltage making it to my condenser fan, when the AC isn't on, the fan blades rotate slowly. There are times, where it does not. I've replaced the capacitor and contactor but no luck. If I disconnect the CCH wires, then this behavior stops. I cannot figure out why this is happening. It originally started when the HVAC guy replaced a capacitor a few years ago. When I mentioned it to him he didn't seem to think much of it.
I don't know why Carrier has one lead of the CCH going to the control board and essentially connecting it with the black fan wire instead of keeping it on the contractor but that's what's called out on the wiring diagram.
The more that I think about this, I'm guessing that normally, there wouldn't be enough electricity flowing through the fan motor to turn it but something is not functioning correctly and allowing enough to turn it. When I measure the voltage on that shared CCH leg (i.e. when it's on the same board connector as the fan motor) there are 97 Volts. in the rare times that the fan isn't turning slowly (might be controlled by the temperature switch) there is 123V on them.
How would you wire it if a double pole contact was installed to replace a single pole. I have a new installation of the Mars 10874 ECM designed to replace PSC fan motors. But with a single pole contractor, the ECM motors get enough current flow through the heater that it makes it spin for a brief 4 seconds and idles for 10 secs and repeats continually.
You can jumper the side of the contactor that is not necessary.
GFM
i wanted to put videos online but my phone want let me bc its a windows phone and i dont have internet in my home bc i live with people who don't have any sense to do nothing with a computer
the reason i think its a york is bc it has a control board in it and york is one of the first heat pumps that had control board the rest mainly had defrost timers back in those days
that looked like a old 1970s or 1980s york heat pump is that the one with a bad reversing valve i tought it was a janitrol but i was wrong
Shouldn't the legs be labeled at 120v on your ladder logic diagram? (120+120=240) ?
+^Gecko^ Actually, no. Because there is no neutral.
GFM
Refrigeration systems the crankcase heater is connected to L1 and L2 on the compressor contactor so it's always on.
wow I was scratching my head on this very topic. Very informative. Big help.Thank you
What If you live in a hotter climate
As usual, great explanation GFM. Question... is it worth turning off the CCH in the summer with ambient say above 60F? Or is that not a good idea.
+Gene Friedman You can if you wish. Just remember to turn the breaker on 24 hours before you turn on the air conditioner.
GFM
Question so if I install a jumper on a 2 pole contactor ,it could cause issue for the compressor?
No. If you are installing a jumper on one set of contacts, you are simply imitating a single pole contactor.
GFM
@@grayfurnaceman thank you for replying back . I was a little confused . I did manage to find the Schematic for the unit. Thank you for making these videos they’ve very helpful when I get stuck .
Could you illustrate the crankcase heater, the double pole contactor AND the discharge line thermostat in another video?
I will put it on the list.
GFM
Good video. Thanks for posting.
Tanks for this video.I t helps me a lot.
Thanks gray....
Welcome
GFM
Cool i like it Thanks GFM what state are you in?
I’m a huge fan of your videos and as a technician myself it’s a great privilege to gain more knowledge from an excellent teacher! May God bless you sir!
Thanks for the support.
GFM
What is the temperature range used for the temperature switch controlling the crankcase heater?
It varies with each manufacturer. Suffice it to say the compressor needs to be above 70F.
GFM
Wondered how they worked, now i know!
Oh okay this makes sense. Thank you for explaining this, you are a great teacher!
Welcome
GFM
Great video GFM . Take care, Brett
what about on a 3 pole
can you make a video about it
I will see what I can do.
GFM
Great video.
Thats why its wired that way. Thanks again friend.
+Ronald Cach Welcome
GFM
Great job!!!
thank you...
Does the crankcase heater function to prevent oil escaping from the compressor?
Indirectly, yes. Refrigerant moves to the coldest and oiliest place. If the crankcase heater keeps the compressor warm, it will keep the refrigerant from traveling to the compressor and mixing with the oil there. If the heat is not there, the refrigerant will foam because it is mixed with the oil and both oil and refrigerant will move out of the compressor.
GFM