Greenheck RL147 Positioner Relay - Manual (Page 5)

RL 147 POSITIONING RELAY Technical Instruction
155-038 Page 5
6. If you have moved the spring guide, you will need to
adjust the spring arm so that the spring is parallel to the
stem or shaft.
7. Check the feedback spring. There should be no slack or
no stretch in it. Adjust the wing nuts and adjustment nut, if
necessary.
8. Fasten the relay cover. Fill in the information on the
calibration label.
Calculating the Span Setting
1. Identify the valve stem from Table 2 or 4. If the stroke of
the No. 6 damper actuator has been changed from the
factory setting refer to Table 7.
2. If your stem travel matches the nominal spring travel listed
in Table 2 there is no need to calculate a new span
setting.
3. If your stem travel does not match the nominal spring
travel listed in Table 2, choose the spring(s) whose
maximum allowable travel is equal or greater than your
actual stem travel.
4. Calculate the span setting with the formula below.
Formula for Span Setting
Span
Setting
= Desired span X
Nominal spring travel
Actuator stroke
Example:
Determine the span setting for a valve having desired
span of 5 psig and 5/16" stroke.
Select a spring with a maximum allowable range equal to or
larger than the stroke. Use the 1/4" spring with a 3/8"
maximum allowable travel range. Refer to Table 2.
Span
Setting
= 5 X
0.25
0.312
= 4
Set the span adjustment tab to line 4 on the feed back arm to
provide a 5 psig span for this valve.
Table 2. Spring Selection.
Spring Travel Range Recommended Springs
Nominal
in. (mm)
Max. Allowable
in (mm) Part No. Size & Color
5/32 (5.0) 1/4 (6.4) 147-298 Small Green
1/4 (6.4) 3/8 (9.5) 147-289 Small Cadmium Plate
3/8 (9.5) 1/2 (13) (2)147-298 Small Green
3/4 (19) 1 (25) 147-290 Small Red
1 (25) 1-1/4 (32) 147-291 Long Green
1-1/4 (32) 1-5/8 (41)
147-289
plus
147-291
Small Cadmium Plate
plus
Long Green
1-1/2 (38) 2 (51) (2) 147-290 Small Red
1-3/4 (44) 2-1/4 (57) 147-290
plus
147-291
Small Red
plus
Long Green
2 (51) 2-1/2 (64) (2) 147-291 Long Green
2-3/8 (60) N/A 147-105 2” Red
3 (76) 3-1/4(83) 147-292 Long Cadmium Plate
3-3/4 (95) 4 (102) 147-301 3” Red
4 (102) 4-1/4 (108) 147-293 Blue
4 (102) 6 (152) 147-313 Zinc Pl. or Yell. Chr.
7 (178) 12-1/4 (311) 147-330 Zinc Plate
Table 3. Stem Travel for VP 591 Bronze Body Valves.
Line Size Stem Travel inches (mm)
in. (mm) Single
Seat
Double Seat WM
1/2 (13) 3/8 (9.5) — 1/8 (3.2)
3/4 (19) 3/4 (19) — 3/16
(4.8)
1 (25) 3/4 (19) 3/16 (4.8) 1/4 (6.4)
1-1/4 (32) 1 (25) 1/4 (6.4) 5/16
(7.9)
1-1/2 (38) 1 (25) 1/4 (6.4) 5/16
(7.9)
2 (51) 5/8 (16) 3/8 (9.5) NO.
5/16 (7.9) N.C.
5/16
(7.9)