jokin
Basic Member
Posts:105
 |
| 24 Dec 2011 10:09 PM |
|
Have a 3 ton Climate master 27. The unit came with a Taco 006 circ pump for the DSH circuit. I connected my desuperheater to a buffer tank a week or so back and I suspected the on board circ pump wasn't coming on. I used my multimeter to determine that the aquastat and discharge temp sensor are sending power to the motor, but it isn't turning and pumping water, because the discharge line just gets reallly warm as the heat migrates out, and the body of the pump stays cool.
I removed the pump&cartridge from the casing/head felt that the impeller and shaft were free and could spin easily, but the rotation wasn't perfectly smooth there was a barely perceptable tick. Anyway I put power to the leads and it spins up dry just fine (starting on its own with no push or anything). I put it back together filled the loop and bled out the air and the pump isn't working. The unit is sending power to the pump, but it won't turn (the pump stays cool, and the DSH discharge pipe just gets warmer and warmer.
I'm not sure what to do? Do I need a new pump cartridge, motor, or both?
|
|
|
|
|
|
|
robinnc
Advanced Member
Posts:586
|
| 24 Dec 2011 10:14 PM |
|
Don't know anything about that but does the pump have it's own fuse?
|
|
|
|
|
joe.ami
Veteran Member
Posts:4377
|
| 26 Dec 2011 10:30 AM |
|
Do you have 110 or 220 going to the pump? What is the DT between entering and leaving water? How did you bleed system? |
|
Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
|
|
jokin
Basic Member
Posts:105
|
| 26 Dec 2011 10:33 PM |
|
I think it has circuit breaker (4 amps), but it is not tripped because I have voltage at the pump -120 on one leg and 120 on the other leg, so 240 volts, which is what the pump needs per the label and model # which I looked up on Taco's website.
As for bleeding the system, I have a bleeder port on the check valve that is the highest point of the DSH loop, I opened that until a solid stream of water comes out, no hissing or air bulbs.
The difference in temperature after about 20 minutes of compressor operation is about 27 degrees and it seems to be steadily getting greater.
I also tried the long screwdriver to the ear test and repeatedly connected and disconnected the pump pig tails, with perceptible change to the sound or vibration I was picking up. I'm fairly certain that once installed on the housing/volute and filled with water the impeller is not turning even though it is getting power. The fact that it starts by itself dry (and off the housing/volute) makes me wonder if I need a new cartridge or a new motor, or both?
Any advice would be appreciated.
|
|
|
|
|
Happywelldriller
New Member
Posts:21
|
| 26 Dec 2011 11:49 PM |
|
Please do not assume you have 240 volts by adding 120and 120. You must measure both hot legs and see a 240 volt on you meter. If not you do not have 240 |
|
|
|
|
jokin
Basic Member
Posts:105
|
| 27 Dec 2011 11:25 AM |
|
Duly noted. I'll check to ensure the proper 240 volts across both hots, but I'm guessing the correct voltage is there because when removed from the housing/volute the pump started just fine connected to the same terminals.
Just wondering if I need a new cartridge, motor/stator, or both.
|
|
|
|
|
joe.ami
Veteran Member
Posts:4377
|
| 29 Dec 2011 09:07 AM |
|
You would have to do a capacitor test as well as volts and amp draw. I also am not clear on how we know it is not air-locked.
J |
|
Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
|
|
jokin
Basic Member
Posts:105
|
| 13 Jan 2012 08:06 AM |
|
Thanks for the responses.
Happy well driller was correct. I was getting 120 volts to ground on both leads, but not 240 across the leads at the motor. So the reason my DSH pump was not starting is either the discharge temperature switch (normally open) is not closing) even after 15 - 20 minutes of compressor operation, or the high limit aquastat (normally closed). The copper line where the aquastat is installed is cold to the touch, so I'm guess its the discharge temperature switch, either stuck, out of calibration/faulty, or the wrong part from the manufacturer.
Someone else with a unit similar to my Climatemaster 27 on the geoexchange website had this to say about this....
" ...............I am posting because others have said that my Carrier 2008 GTPX 50YDHO26PCK301 Model 026 is supposed to be made by Climate Master for Carrier and be essentially the same thing as the CM Tranquility 27. My first comment is that the Taco circulating pump is run in series through two switches one, normally closed contacts on a aquastat on the discharge hot water line AND a set of normally open contacts for the compressor discharge temperature switch (strap on type). The aquastat safety opens at 125 degrees F and stops the circulating pump if it reaches that temperature. The discharge temperature switch is interesting. I had an initial problem on mine getting discharge temperatures higher than 116 - 120 degrees on an open well set up. That factory switch (3 7T32 31596F 135-10 F) is open at less than 135 degrees. It closes at 137 - 143 degrees F For the time being I have removed it because I was getting NO hot water production. (It never closed). So similar owners keep this in mind. Also the unit is R-410a, which is more efficient than R-22. That Taco circulating pump would normally be wired on the load side of the contactor, has circuit breakers, and would be energized when the contactor pulls in. For readers; I am wonderring if my unit has the wrong compressor temperature discharge temperature switch. It seems to me that I need a swich set around 125 degrees. ....... "
With my dedicated buffer / two tank setup, would it hurt to bypass the discharge temperature switch and have the pump always run with the compressor, but still leave the high limit aquastat inline to prevent over heating ? |
|
|
|
|
engineer
Veteran Member
Posts:2749
|
| 13 Jan 2012 08:46 PM |
|
I operate some aftermarket desuperheaters in the manner you describe. Beware that under certain conditions heat exchange may reverse, transferring heat from the tank to the refrigerant. An example of when this may occur is when the system downshifts from high to low stage after sunset on a hot day. The buffer tank may then be quite warm, and refrigerant temperature could be below tank temperature. Operating the pump under those conditions will transfer heat from the tank to the refrigerant.
If the water side is plumbed properly, the effect is minor and fleeting since the thermocline in the tank works in your favor. A bit of water at the bottom of the tank may be slightly cooled but that minimally effects the rest of the tank.
|
|
Curt Kinder <br><br>
The truth is incontrovertible. Malice may attack it, ignorance may deride it, but in the end, there it is - Winston Churchill <br><br><a href="http://www.greenersolutionsair.com">www.greenersolutionsair.com</a>
|
|
|
jokin
Basic Member
Posts:105
|
| 14 Jan 2012 10:02 PM |
Accepted Answer
|
Your point makes sense, its interesting to hear the other perspective from the cooling dominated area. I had to laugh as being in a heating dominated climate I was primarly thinking about DSH production during the heating mode.
I was talking with a guy at work and we thought any time the DSH pump is on and compressor discharge temp is lower than the buffer tank, heat will go from the tank to the refrigerant circuit. In the winter we didn't think this would ever be a problem because it would just heat the refrigerant circuit up faster and the heat would go into my house. In the summer it would depend on the compressor disharge operating pressure / temperature. Any time the refrigerant temperature is less than that of the water in the buffer tank at that time, the DSH pump is moving heat from the buffer tank down the drain, literally since I have a pump and dump system.
So, for now I bypassed the discharge temperature switch, and I'm planning to have a summer /winter switch to disable the DSH pump in the summer. I now have a GE heat pump water heater as my primary tank and am working on a "between tank" circulation pump to allow the primary tank to heat the buffer tank as well during the summer.
Now I just have to watch the buffer tank to see how warm it gets.... if the water entering the GE heat pump water heater is warmer than the setpoint(currently 120) it will trip out on an error. I guess I could also raise the primary tank set point just slightly above the aquastat (high limit safety) for the DSH pump, the Climatmaster literature says the aquastat will disable the pump if the water reaches 125 F. But, raising the setpoint could be bad for the kids and will reduce the COP of my primary water heater. I guess we'll wait and see.
Thanks for the help with this! |
|
|
|
|