Technical Documentation Pressure Independent Characterized ...

J20728 - 04/07 - Subject to change. © Belimo Aircontrols (USA), Inc.
1. Verify that the system is purged and filled to the
proper pressure.
2. Verify pump rotation.
® PICCV
PICCV Test and Balance Procedure
3. Open all valves through the building management
system if the total connected load➀ matches the pump
GPM. Systems with diversity must have a percent of
the valves closed to match the pump GPM.
4. Test total flow by accurate method.*
5. Decrease the pump speed until a flow decrease occurs.
6. Increase the pump speed until the original flow is
reestablished.
PICCV Troubleshooting
1. Is the pump on and rotating properly?
2. Is the pressure differential adequate to produce
design GPM?
3. Is the water temperature at the required level?
4. Is the PICCV installed in the right direction?
5. Is there too much diversity in the system?
6. Does the valve tag GPM match the listed design GPM?
7. Does the ATC signal stroke the valve in the
right direction?
8. Are strainers plugged?
9. Is the coil installed counterflow?
10. Discharge temperature not to required rating:
A. Is reset temperature high enough?
B. Is air by-passing the coil?
C. Are all coil areas heating/cooling uniformly?
11. Room cold complaints:
A. Is there enough throw➁ to penetrate air to the
occupancy level?
➁Throw is the distance discharge air is propelled
in order to reach the occupant level.
B. Test discharge air temperature and stratification.
C. Is the building under a negative pressure?
D. Is the hot water temperature at design?
Resets may not be effective for reheat coils.
Test and Balance Procedure,
Troubleshooting
7. Record system ΔP and provide this value to the
ATC contractor.
8. Perform a “Practical Test” to verify that the designer’s
intent has been met. Taking a leaving air temperature
can quickly verify the operation.
*Accurate Methods
Calibrated circuit setters on main lines
Orifice
Venturi
Equipment pressure drops if the components are clean
Ultrasonic Flowmeter
Pump curves and triple duty valves have less
accuracy than the above listed items
GOOD IDEAS:
Install taps on at least one valve with the largest
DP requirement, or near the end run or near
the DP transmitter.
➀Total connected load is the summation of all
terminal GPM.
Often, engineers will design a pumping system for the
total GPM as listed for all of the coils.
Some engineers will take advantage of diversity and
realize that no more than ± 80% of the valves will be
calling at any one time during normal operation.
For instance, if you have 100 GPM of total
connected load, a pump sized for 80 GPM could
be installed. In this case, if all valves open after
a weekend of being closed, none of the valves will
handle the design flow rate. A requirement of 20%
of the valves would have to be closed to match the
pump to the total connected load.
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