Discussion in 'Maintenance and Troubleshooting' started by Eric D, Feb 4, 2008.
One blink. I'm OK.
One blink, is
no fault in memory. The unit forgets the faults if powered down.
Code 5 is a low air coil temp (FP2 sensor violet color wire). This could be because of a dirty filter, dirty air coil, low air flow, or a faulty sensor. First off, I would try increasing your fan speed if possible. If you have a psc motor, there are 3 different speed taps on the blower motor. If you have ECM, you can adjust via dip switches on the ECM control board.
If you still get the code, I would power down the unit, pull the molex pin, and measure the resistance between the two violet wires. Check your measurements with the attached chart. Let me know what you find...
Just one page?
Yes, this is just the page that is dealing with the resistance readings for both thermistors. Trying to make things less confusing. Any word on the readings?...
I hope he has a 4 digit digital meter. He will never see the differences on an analog meter.
Appreciate the data and info on this unit. The waterflow comes from my well,,, It has a 6.0 GPM unit, this is what the installer recommends.
The unit will run for a minute and pump out a little heat then shuts down. The waterflow runs through a filter from the well. It is there to cut out the sludge etc, I just put in a new filter.
The CMX gauge, I watched it, its solid then shuts down for a second or two then just flashes,,,lockdown. My old climatemaster would blink so many times and you could figure out the issue. This one asks you to short the system, it runs through a program and when its done gives you a LED flash that explains the problem. Id like to try shorting it,,,assuming I dont cause any problems,,rather than bringing in the installer right away,,, is this easily done?
Yes this is easy to do. Just hold the metal part of a screwdriver between the two test terminals for 3 seconds. You will hear a couple clicks and then the CXM will go into a 20 minute test mode. This should give you a little more run time to diagnose the problem. If a fault is detected during test mode, it will drop out of test mode and display the fault that occurred via the number of blinks displayed on the LED. Let me know what you find...
Make darn sure you know where to put the driver. As unit has to be pwered up, if you are in doubt, pay the installer the first time to avoid injury or damage.
Lethal voltages lurk within
Ok, my son just gradutaed from trade school ( Electrical ) and we used his " wiggy " to short the unit. I did this while the unit was on but not running to catch a temp. What happened was the solid LED went off,,,we got 4 flashes then a 10 second break then 4 flashes. It didnt run into a test mode like the manual stated, so Im calling this an FP1 lockout code, going by the chart... Water coil low temperature,,
I do have that Ranco meter there to go on when it reached 46 degrees,,,bleeding the H20 away from returning to the well.. It does have an adjustment for HL and CL...Its not really clear on adjusting,,,Im not sure if this is an issue.
Restarted the unit, ran for about 5 minutes, got about 2 degrees up in the home temp, 85 Degree air blowing through the house... but then it shut off again,,, with the 10 second delay and 4 flashes,,,
Any ideas? Thanks in advance!
Cut-Out Coax - FP1
FP1 below Temp limit for 30
continuous seconds (bypassed
for first 120 seconds of
I would first suspect low or no water flow.
-verify water pump is working
-verify water valve to unit is opening
-Check to see if there is a filter or strainer on the supply line to unit that is clogged
Don't worry about the ranco bleed control for now. A standing column well at 53*F should not drop to lockout temps that quickly. I really think that you should get your installer in there especially if someone has been fiddling with the controls.
Thanks for the reply. Only the Ranco may be off on the settings. The water pump is running as it feeds all the household faucets etc. I will look to where the water comes in to see if the controls are all open.
I do have the water filter, in which I have changed the filter recently. It is only a 30 micron, so I dont know if this is holding up the water coming in.
One other thing, I looked on the CXM board, regarding the FP1 code, it does mention that in colder weather conditions you can "clip" the " JP3". I looked and it wasnt clipped.
When I shorted the board, when is the best time to do this? According the manual, as its entering the test mode, it will show the last fault, I dont know how long it does that before going into test mode, it didnt last time....
Low temp operation is for closed loop systems with antifreeze. Do not clip anything. Call your installer or other qualified technician! Now!
QAS, I have a question. Are we talking about lockout in heating startup (winter mode)?
If so, than aren't we trying to DECREASE air flow as much as possible to maximize high side pressure, which also then brings up evaporator pressure and water coil temperature?
Different tonnages may act a bit differently. Remember that most modern tripouts on most new modern water source heat pumps at startup ARE measuring 30 degrees F at the water coil or just before it at the expansion valve.
This is especially a problem with perfect ductwork that is on the verge of being "too good." (The air flows 'too easily' through it).
My take, as an hvac technician, is that while it is ok to experiment with different air flows, i.e, higher and lower, that higher air flow on a heat pump in winter may aggravate low temperature water coil trip outs by quickly dropping high side pressure (which determines low side pressure) and the temperature at the evaporator.
If you have concrete data / and or experience to the contrary, let me know.
In fact, in case the factory guys are listening, it think it is preferable to have a 60-120 delay on winter fan motor start up to get those pressures up to stave off a 30 degree temperature trip out the first 120 seconds of operation.
I prefer delaying the tripout on low temp by 30 or so seconds (unit won't freeze in that short a time).
Letting refrigerant pile up in a high side coil w/o airflow leads to high pressures and high load on compressor
I do not disagree with that.
Maybe now that we are going to true variable speed motors, engineers could give us a "very low rolling start" on winter startup, speeding up gradually during the first 3 - 15 minutes. I honestly think it would help.
We've replaced more than one pressure switch on CM this past year.
I do not understand the context of what you are saying. Are you saying that you have found several bad pressure switches that are causing unnecessary lock outs? Or that pressure switches are failing on 'new' units?
I'm saying sometimes its simply a bad swicth.
Obviously one needs to measure water and air temps as well as gpm to ensure it's not a water side problem.
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