Spectrapure, Spectrapure®inc, 18 troubleshooting guide for ro/di systems – Spectra Watermakers THE MAXCAP RO/DITM SF-MT-0.5-10 User Manual

Page 7: Testing the ro membrane rejection rate

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SpectraPure

SpectraPure®Inc.

480.894.5437 Call us toll-free 1.800.685.2783

2167 East Fifth St, Tempe, Arizona 85281

®

18

TROUBLESHOOTING GUIDE FOR RO/DI SYSTEMS

1. Low production rate:

a. plugged pre-filters.

i. Replace pre-filters.

b. low water temperature. ii. Heat feed water OR use higher GPD membrane.

c. low line pressure.

iii. Use booster pump OR use higher GPD membrane.

d. high TDS content.

iv. Use booster pump OR use higher GPD membrane.

e. fouled membrane.

v. Clean or replace membrane to restore flux.

f. plugged flow restrictor. vi. Replace flow restrictor & membrane.

2. Zero production rate:

a. Missing flow restrictor. i.

Put flow restrictor in the yellow line.

b. Dried RO membrane.

ii. Try to restore flux by soaking in rubbing alcohol

OR

replace

the

membrane.

c. Plugged flow restrictor. iii. Replace flow restrictor and replace

the

membrane.

3. Extremely high production rate:

a.

Ruptured

membrane.

i.

Replace

b. Very high line pressure (> 80 psi). ii. Use a pressure reducing valve.

4. Pressure gauge does not register pressure when the system is “ON”:

a. Missing flow restrictor.

i.

Put flow restrictor in the yellow

line.

b. Pressure gauge screwed in too far.

ii.

Unscrew pressure gauge one

turn

and

retest.

c.

Plugged pressure gauge orifice.

iii. Clean orifice with a needle.

d. Defective pressure gauge.

iv. Replace it.

5. Low deionization cartridge life:

a.

Defective

membrane.

i.

Replace

it.

b. Low pressure (< 40 psi).

ii. Use booster pump.

c. High CO2 levels in water (> 5 ppm).

iii. Aerate RO product water or use a

straight

anion

cartridge

ahead

of

DI

cartridge.

(Call

Technical

Support)

d. High TDS in feed water (> 1000 ppm). iv. NO EASY SOLUTION.

e. High levels of silica, nitrates,

v.

Use straight anion cartridge

ahead

of

mixed-bed

for

phosphates

etc.

in

tap

water.

f. Bad or faulty DI cartridge.

g. High pH tap water (> 9.0).

vi. Acidify feed water to the RO

membrane

to

improve

its

rejection.

h. Faulty monitor/probe.

Test and Replace if required.

SpectraPure®Inc.

Fax 480.894.6109 Fax us toll-free 1.877.527.7873

E-mail: [email protected] Visit us on the web www.spectrapure.com

7

SpectraPure

®

TESTING THE RO MEMBRANE REJECTION RATE

Procedure:

1. First, make sure that the system has been turned on and producing

water (filling the tank) for 15-20 minutes. (The pressure gauge should

be reading > 40-PSI during this time).

2. Turn on the meter by depressing the “ON” switch then locate the slide

switch on the front of the meter.

A. Measure the tap water conductivity by sliding the switch to

the

Left.

(Call

it

X)

B. Measure RO water conductivity by sliding the switch to the

Right.

(Call

it

Y).

C. Subtract RO water conductivity from tap water conductivity.

(X

-

Y)

D. Divide this quantity by tap water conductivity. (X - Y) ÷ X

E. Rejection = [(X - Y) ÷ X ] ×100

* Conductivity in the above procedure could be caused by hardness,

alkalinity,nitrate, phosphate, silica etc. (The measurement is in ppm or mg/l).

Rejection of the RO Membrane Calculation Example

1. Tap water hardness = 150 ppm (X)

2. RO water hardness = 7 ppm (Y)

3. X - Y = 143 ppm

4. (X - Y) ÷ X = 143 ÷ 150 = 0.953

5. Rejection = [ ( X - Y) ÷ X ] Ч100 = 0.953 Ч100 = 95.3

Membrane Hardness Rejection = 95.3 % : Rejection rates less than 95% may

indicate that the membrane should be replaced.

As a general rule; the RO membrane would be considered to be in good

condition when the rejection rate is = to or > 95%.

NOTE: There are many variables in the input (Tap) water chemistry that may

affect the rejection rate of the RO membrane. (If, after testing the membrane,

there are questions regarding its condition, please call our Technical Support staff

for assistance).

For service or repair of these monitors, please send to:

HM

DIGITAL,

INC

5819

Uplander

Way

Culver City, CA 90230

DM-1 Specifications:
Range

0-1999

PPM

Resolution 1PPM (1-999 PPM)

Accuracy 2%

Probe ¼’’

Power Source (2) 1.5V button batteries

Battery life Approx 1000 hours

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