Heat Pump problem/LTS Switch Lock-Out - http://www.hvacmechanic.com/ Forums
Original message
| Jcal
 |  "Heat Pump problem/LTS Switch Lock-Out"
, posted Sat 8 Nov 19:17  
I have a Climate Master Heat Pump. The short of it is that even with a new TVX valve installed last year and recently a new relay installed, the LTS Lock Out keeps occuring.
Is the problem that the H2O temp is too low(45 Now), and how do I adjust it warmer? Its coming from my well.
Or is it a relay problem still?
If you feel the piping just below the TVX valv it is very cold, almost frosting.
Reduced water flow maybe?
Any help would be wonderful! Its getting cold!
Jcal
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Replies:
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| Xenos
Webmaster 
| "Re(1):Heat Pump problem/LTS Switch Lock-Out" , posted Sat 8 Nov 19:34
If it’s tripping on low temperature and your unit is designed to run with water at 45. I would agree with your diagnoses and say the flow rate is too low. Increasing it will decrease the TD across the evaporator and increase the evaporator’s temperature. If the flow is low it wouldn’t take much to have the temperature drop below 35 in the evaporator. If you have the means to check the temperature you should check what the TD is.
Xenos.
The best way to escape a problem is to solve it.
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| | Jcal
| "Re(2):Heat Pump problem/LTS Switch Lock-Out" , posted Sat 8 Nov 19:45
Thank you so much for your reply and so quickly! Ummm,,,not to be stupid,,,but what are you referring to with "TD" temperature decrease?
If we are to assume that the water flow is too low, is there a way to increase it? and can an amatuer HVAC technician do it?
Thanks again!
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| | Xenos
Webmaster
| "Re(3):Heat Pump problem/LTS Switch Lock-Out" , posted Sat 8 Nov 20:10
TD is Temperature difference. I’m not sure what temperature your control is tripping at but I cant see being lower than 35. To increase the flow you have to either reduce the pressure drop in the system or increase the pumps pressure. As far as the HVAC technician comment we are the jacks of all trades. Pumps and water are plumbing so we have to know a bit about then but a plumper is the pro. So I guess were all a bit amateur :).
Xenos.
The best way to escape a problem is to solve it.
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| | Xenos
Webmaster
| "Re(4):Heat Pump problem/LTS Switch Lock-Out" , posted Sat 8 Nov 20:36
I have been doing some research on your equipment. The low temperature cut out is factory set at 30F and the required flow rate through the unit is 3Gpm per ton. Also I was just thinking about something maybe your water solenoid valve is not opening fully. The TD between the water in and out should be a good guide it should be no more than 10 degrees and at 3 Gpm per ton 45 degree water should be no problem.
P.S. 3 Gpm / ton = 4 to 8 degree TD.
Xenos.
The best way to escape a problem is to solve it.
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| | jcal
| "Re(5):Heat Pump problem/LTS Switch Lock-Out" , posted Sat 8 Nov 21:19
Thank you again! The Taco Solenoid valve was replaced this summer, when I was having difficulty with NO AC,,,OF course now I Have no heat!
I looked at the grey box that regulates the Water Pump. It has 2 screws. One that regulates the on and off cut off switch and the other screw regulates just the pressure of the off. It is difficult to know how to adjust this seeing there is no way I can tell what it is currently set at and how much or which screw to increase.
Also when I attempt to turn unit on the fan comes on, then the water circulates in. It starts to make a "crackling sound" around the TCX valve and shuts off before the pressure is high enough to start the unit. Thus the pipe is cold especially under the TCX valve.
I dont know if I am making any sense to what you are trying to suggest. The H20 is 47 degrees going in the unit also.
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| | Xenos
Webmaster
| "Re(6):Heat Pump problem/LTS Switch Lock-Out" , posted Sat 8 Nov 21:27
The TXC is it a refrigeration device? The reason I as is there is a refrigeration valve referred to as a TXV valve.
Also what turns off before the pressure is high enough to start the unit, the pump?
All I am saying is that you unit can handle this water temperature if the flow rate is 3 GPM/ Ton if it is set for 1.5 GPM /Ton it can’t handle water less than 50.
Xenos.
The best way to escape a problem is to solve it.
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| | Xenos
Webmaster
| "Re(7):Heat Pump problem/LTS Switch Lock-Out" , posted Sat 8 Nov 21:32
Ok lets look at what you have. Entering the unit you have 47 degree water, Now you tell me that down by this valve it’s quite colder. If it is less than 37 degrees with out even thinking about it, right away we know there is not enough water flow to keep the unit going in heating mode. You can test your water flow by turning it on it cooling for a test. BTW what is the tonnage of the unit ?
Xenos.
The best way to escape a problem is to solve it.
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| | jcal
| "Re(8):Heat Pump problem/LTS Switch Lock-Out" , posted Sat 8 Nov 21:50
Youre right, it was a TXV that was replaced. I meant that above this valve the copper piping appeared warmer and the piping below the valve was very frosty, cold to the touch in Heat Mode.
The system worked fine in Cooling mode, with 11GPM.
The water from the well, yes, was 47 degrees.
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| | jcal
| "Re(9):Heat Pump problem/LTS Switch Lock-Out" , posted Sat 8 Nov 21:55
Just to add, yes the LTS kicks in and shuts off the pump before the water flow thats necessary starts.
I have the spec. manual hear,,,I guess Im unclear about tonnage.
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| | Xenos
Webmaster
| "Re(10):Heat Pump problem/LTS Switch Lock-Out" , posted Sat 8 Nov 22:15
what model number is the unit?
Xenos.
The best way to escape a problem is to solve it.
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| | Xenos
Webmaster
| "Re(2):Re(10):Heat Pump problem/LTS Switch Loc" , posted Sat 8 Nov 22:29
Also just to clarify something this switch LTS. Where is it connected to. Is connected to the refrigeration system and is possibly a LPS ?
Xenos.
The best way to escape a problem is to solve it.
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| | jcal
| "Re(3):Re(10):Heat Pump problem/LTS Switch Loc" , posted Sat 8 Nov 22:38
From the manual LTS Low temperature switch-Red Led
This switch opens when the temperature of the water entering the condenser bundle drops below the set point. The low temperature(freeze)LED is lit
Recommendations from manual:
Reduded or no water flow: check pumpoperation and or valve settings adjust to proper flow rate
H2o Temp out of range: Bring water temp to design conditions
Bad Low temp switch: talks about disconnecting then reconnecting main power to reset any tripped saftey switches etc.
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| | jcal
| "Re(2):Re(10):Heat Pump problem/LTS Switch Loc" , posted Sat 8 Nov 22:28
It is an " E Series:Model 024" It was installed in 1997
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| | jcal
| "Re(3):Re(10):Heat Pump problem/LTS Switch Loc" , posted Sat 8 Nov 22:42
It has a seperate LPS Switch Lock-Out.....
Not sure if its connected to Refrige system, Id guess yes,,,like I forementioned, No Problems running the AC a few minitues ago.
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| | Xenos
Webmaster
| "Re(4):Re(10):Heat Pump problem/LTS Switch Loc" , posted Sat 8 Nov 22:46
Is the pump powered of the same contactor as the compressor. IF its not a time delay may solve you problem in these low temperature times. By holding off the compressor for 1 minute this would allow the pump to get to pressure as well I am actually questioning the validity of the sensor at this point. Do you think your hitting 30 degrees that fast? I cant see it. Though it’s possible. You should check the temperature of the piping where the sensor is.
Xenos.
The best way to escape a problem is to solve it.
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| | jcal
| "Re(5):Re(10):Heat Pump problem/LTS Switch Loc" , posted Sat 8 Nov 22:58
I agree,, I dont think its hitting 30 that fast. Id guess that water flow lasts about 2 minutes before the LTS shut down kicks in. I will try tommorrow AM the temp near sensor, if I can find it. I will also try to locate a valve setting to increase the water pressure, although Ive found nothing near the water holding tanks and nothing coming from the pipes out of the ground into the house, except that gray box with 2 screws to adjust pressures,,,,I guess thats it, would have to guess at adjustments,,,trial and error.
Thanks for hanging in there with me! I will let you know what more I can figure out,,,,in the AM
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