Spectra Watermakers MEM-90,150, SF-MT-0.5-10 Testing The Ro Membrane Rejection Rate, SpectraPure

SpectraPure®

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
	f.	Bad or faulty DI cartridge.		phosphates etc. in tap water.
	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. 480.894.5437 Call us toll-free 1.800.685.2783
18	2167 East Fifth St, Tempe, Arizona 85281

SpectraPure®

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

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

HM DIGITAL, INC

5819 Uplander Way

Culver City, CA 90230

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 ] ×100 = 0.953 ×100 = 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).

SpectraPure®Inc. Fax 480.894.6109 Fax us toll-free 1.877.527.7873 E-mail: spectra@spectrapure.com Visit us on the web www.spectrapure.com 7