37
Minimum Load Valve (MLV) Auto-Component
Test —
Minimum load valve is also referred to as hot gas by-
pass valve (HGBV).
The hot gas bypass auto-component test requires the follow-
ing conditions:
1. Unit is not shut down due to failure (A152).
2. MLV=ENBL.
3. No compressors are on or requested on.
4. Compressor A1 is available to start.
The test screen will display the following:
The MLV auto-component test functions by comparing the
discharge pressure when MLV is closed to that when MLV is
open, and verifying DP.A decreases by at least AC_MLVDR.
The auto-component MLV deadband (AC_MLVDR) will
default to 5 psig with a range of 0 to 10 psig.
Setting T.MLV=ON will perform the following:
1. Command A1 ON and MLV OFF.
2. Let circuit stabilize for 5 minutes and save DP.A
(recorded).
3. Command MLV ON.
4. Let circuit stabilize for 5 minutes and record DP.A
(current)
5. Verify DP.A (recorded) - DP.A (current) > AC_MLVDR.
6. End test.
If DP.A (recorded) - DP.A (current) > AC_MLVDR then
ML.ST=PASS, otherwise ML.ST=FAIL.
Supply Fan Auto-Component Test — The supply
fan auto-component test requires the following conditions:
1. Unit is not shut down due to failure (A152).
2. Supply fan VFD not in bypass mode.
3. Power exhaust or return fan (if enabled) not in bypass
mode.
4. Supply fan not on.
The test screen will display this:
The supply fan auto-component test functions by com-
manding the supply fan to minimum speed (STATPMIN), and
verifying that VFD power (S.PWR) and duct static pressure
(SP) is increasing.
Setting SF.TS=ON will perform the following:
1. Record S.PWR and SP.
2. Command S.VFD to STATPMIN and let run 5 minutes.
3. Verify S.PWR increases.
4. If SP.CF=ENBL and SP.S=ENBL, verify SP increases.
5. End test.
After letting the supply fan run and stabilize for 5 minutes,
the control will verify S.PWR has increased and SP (if en-
abled) has increased.
If both S.PWR and SP (if enabled) have increased,
SF.ST=PASS, otherwise SF.ST=FAIL.
Power Exhaust Fan Auto-Component Test —
The power exhaust fan auto-component test requires the fol-
lowing conditions:
1. Unit is not shut down due to failure (A152).
2. Supply fan VFD not in bypass mode.
3. Power exhaust fan VFD not in bypass mode.
4. BP.CF=VFD PWR EXH (Building pressure is controlled
by exhaust fan).
5. Supply fan not on.
6. Power exhaust not on.
Test screen will display the following:
The power exhaust fan auto-component test functions by
commanding the supply fan to minimum speed (STATPMIN)
and verifying that exhaust VFD speed (E.VFD) and power
(E.PWR) increase while building pressure (BP) is modulated
to within ± AC_PE_DB of BPSP. AC_PE_DB will have a de-
fault value of 0.02 in. wg and a range of 0 to 0.25 in. wg.
Setting (PE.TS) =ON will perform the following:
1. Record E.PWR and E.VFD.
2. Command S.VFD to STATPMIN.
3. Open economizer to ECONOMIN.
4. Allow building pressure task to modulate E.VFD and let
run 5 minutes.
5. Verify E.VFD increases.
6. Verify E.PWR increases.
7. Verify BP within BPSP ± AC_PE_DB.
8. End test.
ML.TS No Run MLV/HGBO Auto-Test
ML.DT Running 1/1 Test Status and Timer
MLV Off Minimum Load Valve Relay
DP.A 331.3 psig Cir A Discharge Pressure
ML.ST Running MLV/HGBP AutoTest Result
45
40
35
30
25
20
50
70
90
110
130
Delta Pressure (psi)
Outdoor Air Temperature (F)
∆P cond A
Poly. (∆P cond A)
∆P cond B
Poly. (∆P cond B)
y = 0.0003x
3
+ 0.0985x
2
- 10.336x + 389.27
R
2
= 0.997
y = 0.0003x
3
+ 0.098x
2
- 10.176x + 378.29
R
2
= 0.9958
Fig. 5 — Plot C: OAT vs Delta Condenser Pressure
a48-8787
SF.TS No Run Supply Fan Auto-Test
SF.DT Running Test Status and Timer
S.VFD 0% VFD1 Actual Speed %
S.PWR 0.00 kW VFD1 Actual Motor Power
SP 0.00˝ H20 Static Pressure
SF.ST Pass SF Auto-Test Result
PE.TS Off
PE.DT Running Fans
S.VFD 0%
E.VFD 0%
E.PWR 0.00 kW
BP 0.00 H20
BPSP 0.05 H20
PE.ST Not Run
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