Lo P1 Error on Thermoflex 900/1400/2500 Chiller
Issue:
Environment:
- ThermoFlex 900
- ThermoFlex 1400
- ThermoFlex 2500
Resolution:
Prerequisite: It has been confirmed that the correct voltage is applied: 115V for a ThermoFlex 900 or 1400; 220V for a ThermoFlex 2500 chiller.
If the Thermoflex 900/1400/2500 chillers displays a “Lo P1” error on the front LCD display, it is possible that air is trapped at the pressure sensor or the pump is cavitating.
Change the Lo P1 pressure setting to 3psi and the delay to 30s. See pages 26-27 of the ThermoFlex Operators Manual linked here: U00933 - Rev. 06/01/07 - ThermoFlex Installation, Operation and Basic Maintenance, excerpt to follow, for steps on how to navigate the Setup Loop to make these changes.
Observe if water flows into the reservoir before the ‘Lo P1” error is displayed.
If water is flowing into the reservoir, follow steps 1-4 to attempt to release the trapped air or debris in the pressure transducer.
If NO water is flowing into the reservoir, follow steps 5-8 to remove trapped air in the pump head or prime the pump.
Water is Flowing into the Reservoir
If there is plenty of fluid returning to the reservoir, the pressure transducer may not be reading the correct pressure and is therefore causing the shutdown
1) Remove the Side Panels by referencing the steps below or video linked here: How to Remove the Cover on a ThermoFlex 900 / 1400 / 2500 Chiller.
a) Use a Philips head screwdriver to remove the five #6-32 x 1/4" screws indicated in the illustrations below.
b) Slide the right panel back approximately one inch, then lift slightly from the rear to disengage the panel's two tabs from their slots.
The pressure transducer will be accessible from the right side of the chiller.
2) Detach the Pressure Transducer
3) Unscrew the Pressure Transducer receptacle and clean the connector of any debris that may have accumulated.
4) Power on the chiller and with the water flowing, press on the valve stem until water is flowing out of the valve.
5) Reconnect the Pressure Transducer receptacle followed by the Pressure Transducer itself and confirm that the “Lo P1” error no longer occurs. If the problem is not resolved, then replace the Pressure Transducer using this knowledge article as a guide to do so: Pressure Transducer Replacement.
Water is NOT Flowing into the Reservoir
It is possible that the pump is still functional, but the pump head may be air locked or that the pump is cavitating. To remove potentially trapped air in the pump head or to prime the pump, follow these steps.
1) Disconnect the “PROCESS OUT” tube from the Quick Disconnect (QD) fitting at the back of the chiller and in its stead connect an ~1 ft long piece of tube.
Note: If you don’t have any spare tubing and the lines between the chiller and instrument has sufficient excess, a 1 ft piece can be cut from the return or supply line.
2) Point the 1 ft section of tubing connected to the Process Out into a bucket.
3) Turn the chiller on long enough to allow the pump to engage and purge water. This will typically take 2-3 second. Then power off the chiller. The goal is to get the chiller powered off before the P1 interlock occurs.
Note: This action may need to be repeated more than once to clear trapped air.
4) Once water is pumping into the bucket, turn off chiller and reconnect supply line to instrument to the Process Outlet on chiller for normal operation.
5) If water is still not flowing into the reservoir, try bleeding out potentially trapped by doing the following.
a) Remove the right cover by following the steps in step 1 at the top of this knowledge article.
b) Tap on the purge valve, pictured below, with a wrench. This may loosen the ball bearing inside if it is stuck. Then loosen the Nut, pictured below, to let out any trapped air.
Note: the picture below is inverted.
c) If step 5(a) doesn't resolve the Lo P1 issue, try doing the following:
i. Remove the nut, picture in step 5 (a), completely.
ii. Remove the Purge Valve from the Purge Valve stem, being careful to leave the Purge Valve stem in the discharge line. Using 2 wrenches can help in this endevour with one being placed on the Purge Valve stem to hold it while the other wrench is placed on the Purge Valve itself and used to disconnect it from the Purge Valve Stem
iii. Get a clean towel/rag and place it over the Purge Valve Stem.
iv. Power on the chiller. As soon as the towel/rag is wet, power the unit Off. Note: Be ready to act fast because this will all transpire in 2 seconds or so.
v. Reattach the Purge Valve to the Purge Valve Stem and then re-tighten the nut onto the Purge Valve assembly.
Cause: