Nelson MR User guide

Nelson Irrigation Corp. 848 Airport Rd. Walla Walla, WA 99362-2271 USA Tel: [phone] Fax: [phone] E-mail: [email protected] Web site: www.nelsonirrigation.com
MR/MRDC
MDC Guide
TECHNICAL APPLICATION GUIDE
FOR MINI-REGULATOR WITH AND WITHOUT DRAIN CHECK OPTIONS
1.0 REGULATING WATER PRESSURE
& DRAIN CHECK
2.0 HOW IT WORKS
3.0 OPERATION DETAILS
3.1 MR (mini regulator)
3.2 MRDC/MDC drain check function
3.3 Low temperature caution
4.0 TYPICAL APPLICATIONS
4.1 Rotator orchard sprinkler
4.2 Overtree cooling
4.3 Drip lines
4.4 Rotator for wheel lines
4.5 Green house irrigation
5.0 TECHNICAL PERFORMANCE DETAILS
5.1 Pressure options
5.2 Flow effect on outlet pressure
5.3 Performance considerations
5.4 Minimal required pressure input
5.5 Design considerations
of pressure control
5.6 Flow limits
5. 7 Filtration requirements
6.0 OPTIONAL MODELS
7.0 MATERIAL LIST OF PARTS
WARRANTY
1
TABLE OF CONTENTS
R2000 ROTATOR®
WITH MINI REGULATOR
MRDC-AP 11/14
MR/MRDC/MDC

Nelson Irrigation Corp. 848 Airport Rd. Walla Walla, WA 99362-2271 USA Tel: [phone] Fax: [phone] E-mail: [email protected] Web site: www.nelsonirrigation.com
MR/MRDC
MDC Guide
HOW IT WORKS
1.0 REGULATING WATER PRESSURE AND DRAIN CHECK
The purpose of this regulator is to adjust varying water pressure on the irrigation sprinkler, rotator or drip
irrigation system. The result is consistent flow and uniform irrigation. The MRDC also includes the drain-
check benefit for retaining the water in the irrigation pipeline that would otherwise drain out through the
lower sprinklers and create wet spots at the lowest area. The MDC model provides drain check as well but
is used only when regulation is not required. Both the MRDC and MDC restricts operation until adequate
pressure is available to irrigate properly.
2.0 HOW IT WORKS
The mini-regulator (MR) is normally open. The water pressure output is regulated. By contrast the mini-
regulator drain check (MRDC) and mini-drain-check (MDC) are normally closed. They will open only if
minimum operating pressure is provided. The different effect on Rotators is shown by these drawings of
three typical pressure conditions.
MINI REGULATOR (MR)
& MIN REGULATOR
DRAIN CHECK (MRDC)
Outlet (regulated
pressure)
Inlet (keep
pressure above
regulator rating)
2
MR/MRDC
PRESSURE RATING
OPTIONS:
20 PSI (1.4 BAR); 30 PSI (2.0 BAR)
35 PSI (2.4 BAR); 40 PSI (2.8 BAR)
45 PSI (3.1 BAR); 50 PSI (3.4 BAR)
FLOW RANGE:
0.5 - 5 GPM (1.8-18.9 LPM)
(flow
not regulated)
(flow
not regulated)
With adequate pressure, the MR and MRDC regulate
to design pressure but the MDC is open fully and does not regulate.
(flow
not regulated)
With low pressure, the MR is open, the MRDC and MDC are closed to draining.
With no pressure, the MR is open, the MRDC and MDC are closed to draining.

Nelson Irrigation Corp. 848 Airport Rd. Walla Walla, WA 99362-2271 USA Tel: [phone] Fax: [phone] E-mail: [email protected] Web site: www.nelsonirrigation.com
MR/MRDC
MDC Guide
OPERATION DETAILS
3.0 OPERATION DETAILS
All models of the regulator work the same while regulating. The difference between the options is in the
check operation. This cut-away drawing shows how the regulator and the check works.
3.1 MR (MINI REGULATOR)
The MR regulator will allow water flow but does not provide any pressure control benefit until the rated inlet
pressure is provided. Any additional pressure is then regulated to keep the irrigation constant. Provide a 5
PSI pressure margin to have the most accurate pressure regulation.
3.2 MRDC/MDC DRAIN CHECK FUNCTION
The check will not open until minimum pressure is provided to the base of the MRDC and MDC. Minimum
pressure to open is approximately 13 psi below rated pressure. For the MRDC, exact regulation will not
take place until the minimum inlet pressure is reached. Provide an additional 5 psi pressure margin to
have the most accurate pressure regulation. The MRDC and MDC work the same but the MDC does not
regulate pressure.
3.3 LOW TEMPERATURE CAUTION
The MRDC and MDC are not designed for operation below freezing. Remove the MRDC or MDC and drain
the irrigation pipes during freezing conditions otherwise ice can damage the system. THIS PRODUCT IS
NOT RECOMMENDED FOR USE IN FREEZING CONDITIONS.
MRDC AND MDC
FUNCTION AS
A CHECK (NO FLOW)
MR AND MRDC OPERATING AS
A REGULATOR (REGULATED
FLOW) - THE MDC WILL BE FULLY
OPEN BUT DOES NO PRESSURE
REGULATION
regulated pressure
3

Nelson Irrigation Corp. 848 Airport Rd. Walla Walla, WA 99362-2271 USA Tel: [phone] Fax: [phone] E-mail: [email protected] Web site: www.nelsonirrigation.com
MR/MRDC
MDC Guide
TYPICAL APPLICATIONS
4
4.0 TYPICAL APPLICATIONS
4.1 ROTATOR ORCHARD SPRINKLER.
Orchards are commonly planted on
sloping terrain. The MR and MRDC are
useful to deliver equal water top and
bottom. The MRDC is additionally useful
to keep the water in the pipe from draining
to the low area to reduce wet spots in the
low end of the field. The MDC is useful
where pressure regulation is not required
but holding the pipes full of water is
necessary.
4.2 OVERTREE COOLING
The spray of water over apples and other orchard crops is a common practice that can prevent damage
due to heat and sunburn. The check feature of MRDC and the MDC prevents drainage of the system pipes
in-between frequent on-and-off cycles of the cooling irrigation system. The result is more efficient on-off
cooling cycles. Growers like the quick start-up of the sprinklers to rapidly wet the fruit.
4.3 DRIP LINES
The low pressure operation of drip lines requires exact pressure control. Slight variations caused by pump
pressure or elevation can cause undesirable irrigation uniformity. The MR is very useful in controlling the
pressure on the drip line. The MRDC and MDC are useful in keeping the submains full of water.
4.4 ROTATOR FOR WHEEL LINES
The adequate pressure on Rotator sprinklers is essential for uniform irrigation. Wheel lines are commonly
put on undulating land. The pressure can also vary as adjacent wheel lines are turned on and off. In this
condition, the regulator will keep the flow rate the same from each sprinkler (it is essential the minimum
pressure is available).
Save power and water by being accurate in the amount of water out of each device. Caution: The drain-
check feature of the MRDC or MDC is not good for wheel lines because the pipes must be empty in order
to move the wheel lines. Use only the MR on wheel lines because pipe drainage is needed.
4.5 GREEN HOUSE IRRIGATION
The drain check will keep the sprinklers from dripping or draining after shut off and quick start-up.
Same flow top
to bottom

Nelson Irrigation Corp. 848 Airport Rd. Walla Walla, WA 99362-2271 USA Tel: [phone] Fax: [phone] E-mail: [email protected] Web site: www.nelsonirrigation.com
MR/MRDC
MDC Guide
TYPICAL PERFORMANCE DETAILS
5.0 TECHNICAL PERFORMANCE DETAILS
5.1 PRESSURE OPTIONS
The regulator pressure options are for outlet pressure of 20 psi, 30 psi, 35 psi, 40 psi, 45 psi and 50 psi. The
regulator pressure output is set by the spring installed at the factory. The regulator is not field adjustable.
5.2 FLOW EFFECT ON OUTLET PRESSURE
The above graph shows that the mini-regulator outlet pressure slightly decreases as the flow increases. This
slight reduction in nozzle flow is typical for pressure regulators and is very small.
5.3 PERFORMANCE CONSIDERATIONS
The MR is always open and creates very little nozzle turbulence. The worst case for turbulence is for the MRDC
or MDC to be in a partially open condition. The problem is avoided by operating above the recommended
minimum pressure
SPECIAL WARNINGS!
1. Always maintain a minimum of 5 PSI above the nominal pressure rating to avoid severe distortion of
sprinkler distribution patterns and decreased flow.
2. Remove the MRDC or MDC and drain the irrigation system during freezing conditions to prevent damage to
the irrigation system. THIS PRODUCT IS NOT RECOMMENDED FOR USE IN FREEZING CONDITIONS.
3. Partial plugging of the MRDC inlet can cause severe distortion of distribution patterns and decreased flow.
4. The maximum recommended inlet pressure is 130 PSI.
5. This product requires flow through it to regulate pressure. IT IS NOT RECOMMENDED FOR USE IN
CONTINUOUSLY STATIC CONDITIONS.
6. If subsurface application is needed then it is OK to bury the MR and MRDC but, consideration should be
given to maintenance access and debris plugging before burying the regulator.
OUTLET PRESSURE
(PSI)
INLET PRESSURE (PSI)
MINI REGULATOR PERFORMANCE GRAPH (30, 40 and 50 PSI model)
5
1 GPM
2 GPM
3 GPM
4 GPM
5 GPM
40 PSI
30 PSI
20 PSI
5 GPM
4 GPM
2 GPM
3 GPM
1 GPM
2 GPM
3 GPM
4 GPM
5 GPM
1 GPM
10 20 30
15 25 35
29
27
25
23
21
45
55
40 50 60 70 80 90
41
43
45
39
37
35
51
49
47
55
53
57
50 PSI
100
31
33

Nelson Irrigation Corp. 848 Airport Rd. Walla Walla, WA 99362-2271 USA Tel: [phone] Fax: [phone] E-mail: [email protected] Web site: www.nelsonirrigation.com
MR/MRDC
MDC Guide
PRESSURE FACTS
66
5.4 MINIMAL REQUIRED PRESSURE INPUT
The performance curves show the resulting outlet pressure for several rates of flow. The reason to be
concerned about pressure loss is to know the minimum pressure required by the regulator to operate. On
the MR the desired condition is on the flat portion of the performance curve. On the MRDC, always maintain
5 PSI above the rated pressure to have the best performance. The MRDC has a unique characteristic that
requires adequate pressure to open. The regulator then maintains the correct outlet pressure as long as the
necessary inlet pressure is provided. During transition (in-between check and regulation) the MRDC is partially
open. Within this transition a lower than wanted outlet pressure and turbulence will result. The sprinkler may
operate but at a very low pressure that could result in poor water distribution! A partially opened MRDC
regulator can cause severe distortion of the stream and a poor sprinkler distribution pattern.
BE ALERT TO PRESSURE EFFECT UPON THE DRAIN CHECK!
Another unique feature about the MRDC is the difference in opening and closing. The graph shows
performance depending upon if the pressure is increasing (green line) or decreasing (red line). When pressure
is decreasing (like when a pump stops), the check shuts-off at a lower pressure than it opened. It is typical
that sprinklers for the next irrigation
set are turned on before the last
set sprinklers are turned off. Thus
the output will follow the increasing
pressure performance line.
The graph for the MDC performance
is shown here. The red means that
the drain check is closed. Notice that
there is a transition area between
closed and fully open. Inlet pressure
must be available to stay above the
transition area.
SOLUTION: The solution is to always
provide the necessary pressure to the
MRDC and MDC.
CAUTION: Do not operate at a
pressure lower than the minimum
inlet pressure.
EXAMPLE: The 50 PSI MRDC should
be operated at 55 PSI minimum
inlet pressure to stay well above the
check-transition zone.
3.0
2.0
INLET PRESSURE (PSI)
normal #16 nozzle
regulated flow
MR regulator without check
30 40 50 60 70
check opening (increasing pressure)
check closing
(decreasing pressure)
EXAMPLE PERFORMANCE FOR 50 PSI MRDC
Flow
(GPM)

Nelson Irrigation Corp. 848 Airport Rd. Walla Walla, WA 99362-2271 USA Tel: [phone] Fax: [phone] E-mail: [email protected] Web site: www.nelsonirrigation.com
MR/MRDC
MDC Guide
DESIGN CONSIDERATIONS
7
5.5 DESIGN CONSIDERATIONS
OF PRESSURE REGULATOR CONTROL
You can use the pressure regulator for doing a better job
of irrigation. Examine the design pressure and elevation to
decide if regulators are needed. Look at uneven topography
to decide if there is an advantage in reducing runoff caused
by slope and draining of pipes. Regulators can be used
under any condition but the purpose is gained by regulating
the flow. Notice that if conditions are above the diagonal
line on the graph then be certain to use pressure regulators.
If adequate pressure is available then the regulator works
otherwise it remains open.
Consider the savings for lower demand on pump power
because of the reduced initial start-up flow surge. Some
power rates are based upon the peak power demand.
Keeping the pipe full will reduce the time of pumping to fill
empty lines. The peak power is also reduced resulting in
lower power charges.
5.6 FLOW LIMITS
Don’t use the mini-regulator for more than 5 GPM flow. The maximum flow through the regulator depends
upon the acceptable pressure that can be burned up across the regulator. Always maintain 5 psi above the
nominal pressure and keep the flow rate at 5 GPM or lower.
5.7 FILTRATION REQUIREMENTS
The regulator has small openings in the seat and plunger area. Debris smaller than 0.08” (1/16”) may
easily pass through the regulator. Larger material and stringy fibers (such as snail shells) can plug inside
the regulator seat area. Access to remove the plug is gained through the inlet of the regulator.

Nelson Irrigation Corp. 848 Airport Rd. Walla Walla, WA 99362-2271 USA Tel: [phone] Fax: [phone] E-mail: [email protected] Web site: www.nelsonirrigation.com
MR/MRDC
MDC Guide
8
MODELS/MATERIAL LIST
WARRANTY AND DISCLAIMER
The Nelson Mini Regulator, Mini Regulator Drain Check and Mini Drain Check are warranted for one year from date of original sale to be free of defective materials and workmanship when used
within the working specifications for which the product was designed and under normal use and service. The manufacturer assumes no responsibility for installation, removal or unauthorized
repair of defective parts. The manufacturer’s liability under this warranty is limited solely to replacement or repair of defective parts and the manufacturer will not be liable for any crop or other
consequential damages resulting from defects or breach of warranty. THIS WARRANTY IS EXPRESSLY IN LIEU OF ALL OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR PARTICULAR PURPOSES AND OF ALL OTHER OBLIGATIONS OR LIABILITIES OF MANUFACTURER. No agent, employee or representative of the
manufacturer has authority to waive, alter or add to the provisions of this warranty, nor to make any representations or warranty not contained herein. The Mini Regulator Drain Check is covered
by the following U.S. Patents: 5875815, 5257646, and other pending US and Foreign Patents.
6.0 CONNECTION
OPTIONS PART LABEL MATERIAL
SPRING (only used in MRDC) 302 Stainless
RETAINER XENOY
DIAPHRAGM PLUNGER ASSEMBLY Buna-N
PLUNGER XENOY
SPRING (controls model pressure rating) 302 Stainless
HOUSING ASSEMBLY Polyester
O-RING Buna-N
SEAT (different for MDC) Polyester/
Glass
OUTLET CAP (color-coded) Polyester
MR Plunger
Assy.
#10037
MRDC/MDC
Plunger
Assy. #10007
MRDC MR MDC
(brown outlet) (gray outlet) (green outlet)
11102-0XX 11102-1XX 11102-2XX
10394-0XX 10394-1XX 10394-2XX
NOTE: XX denotes pressure option
(i.e. 11102-130 is a 30 PSI 1/2” MNPT
Mini Regulator)
OPTIONS
1/2” MNPT
Male Acme
7.0 MATERIAL LIST OF PARTS
1/2" MNPT X MALE ACME THD 1/2" MNPT X 1/2" MNPT THD 1/2" FNPT X 1/2" MNPT THD1/2" FNPT X MALE ACME THD1/2" ACME X MALE ACME THD
1/2" ACME X 1/2" MNPT THD
1/2" MNPT X MALE ACME THD 1/2" MNPT X 1/2" MNPT THD 1/2" FNPT X 1/2" MNPT THD1/2" FNPT X MALE ACME THD1/2" ACME X MALE ACME THD
1/2" ACME X 1/2" MNPT THD
1/2" MNPT X MALE ACME THD 1/2" MNPT X 1/2" MNPT THD 1/2" FNPT X 1/2" MNPT THD1/2" FNPT X MALE ACME THD1/2" ACME X MALE ACME THD
1/2" ACME X 1/2" MNPT THD
1/2" MNPT X MALE ACME THD 1/2" MNPT X 1/2" MNPT THD 1/2" FNPT X 1/2" MNPT THD1/2" FNPT X MALE ACME THD1/2" ACME X MALE ACME THD
1/2" ACME X 1/2" MNPT THD
1/2" MNPT X MALE ACME THD 1/2" MNPT X 1/2" MNPT THD 1/2" FNPT X 1/2" MNPT THD1/2" FNPT X MALE ACME THD1/2" ACME X MALE ACME THD
1/2" ACME X 1/2" MNPT THD
1/2” MNPT
outlet
1/2” MNPT
outlet
Acme
outlet
Acme
outlet
Acme
outlet
1/2” FNPT
inlet
1/2” MNPT
inlet
1/2” FNPT
inlet
Acme
inlet
1/2” MNPT
inlet