[Nicko]

Hi People,

A little advice needed i feel.

I have just bought a 75GPD from Ro-Man as i only use around 200l per day so in theory the system should be adequate for my requirements. I have fitted everything as per instructions and checked all TDS readings etc which read:

330 feed:
6 pre DI
0 post DI
450ish waste.

All this i think is ok...... I hope.

My feed water pressure is 50psi, however i have run the system for 24hrs and checked the production rate which i can estimate give or take 20L is 150L. This has confused me as a 75GPD system should produce 285L per day. So my questions are:

Is my feed pressure enough?
If not what is a good feed PSI
Do i need a booster pump?
Will it save on waste water as i am on a water meter?
Should i upgrade to a larger system just to combat this the production issue?

Many thanks

Nick

[d s windowcleaning]

youd be better upgrading to a 200 gpd  , you only need a extra membrane housing and a extra filter housing should cost much more than £50 if you look on ro-man site i think it shows a diagram on how to upgrade .

[Alex Gardiner]

The 75 gpd rating is somewhat confusing.  All RO membranes are rated under ideal conditions.  These usually equate to 25 degrees centigrade input water temperature and 80 input pressure.

A variance in any of the above conditions will greatly affect your water production.  At this time of year your water temperature input (from the underground main) will be about 10 degrees centigrade. Some experts say that you lose 5% production ability for each 1 degree drop in temperature.  Your input water pressure will also greatly affect production rates.  I have calculated your expected production rate from your system with your set up to be about 115 litres a day. The only way of improving on this is to increase the number of membranes or add a booster pump.  Probably the simplest way is to add a second membrane.  This will also have the effect of reducing your waste water.

[Nicko]

Thanks for the advice Alex. Another membrane it is.

[Nicko]

Cheers Dave !