21
any of them appear excessively worn.
4.
The roller assemblies have nylon bushings and do not require lubrication and should never be
lubricated.
5.9 ELECTRONIC CONTROLS
1. There is a non-fused disconnect on the control panel door under a weather proof cover.
2. Make a general check for possible problems – frayed wires, loose relays, overheated parts, etc.
3. There are two
Variable Frequency Drives
(VFDs) in the control panel. They are labeled “2VFD” and
“3VFD”. 2VFD and 3 VFD work in tandem and modulate the speed of the reactivation and condenser
fans to maintain a constant discharge pressure on refrigeration circuit (see 4.11). The HCU 4000,
6000, and 8000 have 4VFD to set the speed of the supply fan. (To adjust the air volume, see 4.10). If
a VFD is replaced, the “n” parameters must be set as shown in the Appendix. Note: the non-bolded
parameters are preset from the factory. The
bold
parameters must be set per the appendices.
4. There is a
microprocessor
inside the control panel. The microprocessor is solid state and very
reliable and will probably never need replacement. If it should need replacement, turn off all power to
the unit. Unplug each of the modular wire harness plugs from the top and bottom of the
microprocessor. The microprocessor mounts on a standard DIN rail. Using a small screwdriver, lift the
latching devices and remove the unit from the DIN rail. Snap the new microprocessor onto the DIN
rail and plug the wire harnesses in. Turn on power and the unit is ready to run.
5.10 CHECKING THE DRIP TRAY AND DRAIN
The evaporator coil can cause quite a bit of water to condense out of the incoming air. Normally, this
water is collected in a drip tray under the evaporator coil. The water is then drained away through a P-
trap and drain line. There should be no more than a minimal amount of water under the evaporator coil. If
a lot of water has collected here, the drain line may be blocked. If water is being blown off of the coil, one
of three problems may exist:
1.
The supply air volume is greater than the maximum and water is blowing off of the coil
2.
The drain trap is either missing, dry, damaged or improperly designed allowing air to be drawn
through the drainpipe and spraying water out of the drain pan.
5.11 REMOVING AND REPLACING THE HONEYCOMBE
®
WHEEL, DRIVE BELT,
AND/OR SEALS
Work carefully when removing and replacing the wheel. The wheel is heavy and will require an assistant
to help.
You will need normal hand tools. Turn off the unit. Switch off the power supply to the unit and lock it out
so that nobody else can turn it on by mistake.
1. Open both doors on the condenser end of the unit. Remove the access panel on the bulkhead
between the condenser section and the reactivation plenum.
2. Press the drive idler roller down and remove the belt from the idler roller and from around the drive
pulley. Disconnect the electrical wiring and flexible conduit from the drive motor. Remove the drive
motor and the idler arm assembly.
3. Slide a board underneath the desiccant wheel as a lever and lift the wheel off of the rollers. Lift out
the axle and roller assembly, leaving the roller support bracket in place.
Summary of Contents for HCUw
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Page 75: ...45 USER S MANUAL SYSDRIVE 3G3JVSERIES ...
Page 93: ...63 3G3JV Maintenance Operations Chapter 9 Chapter 9 List of Parameters ...
Page 114: ...84 Appendix F Gas Afterheat ...
Page 119: ...89 Figure 1 Parts Location Wiring Diagram Pictorial ...