Carrier 50PSW036-360 Water Quality Guidelines, Condition Closed Open Loop and Recirculating Well

		Table 2 — Water Quality Guidelines
CONDITION	HX	CLOSED	OPEN LOOP AND RECIRCULATING WELL**
	MATERIAL*	RECIRCULATING†

Scaling Potential — Primary Measurement

Above the given limits, scaling is likely to occur. Scaling indexes should be calculated using the limits below.

pH/Calcium	All	N/A	pH < 7.5 and Ca Hardness, <100 ppm
Hardness Method
Index Limits for Probable Scaling Situations (Operation outside these limits is not recommended.)

Scaling indexes should be calculated at 150 F for direct use and HWG applications, and at 90 F for indirect HX use. A monitoring plan should be implemented.

Ryznar Stability Index	All	N/A		6.0 - 7.5
				If >7.5 minimize steel pipe use.
Langelier Saturation Index					–0.5 to +0.5
	All	N/A		If <–0.5 minimize steel pipe use.
			Based upon 150 F HWG and direct well, 85 F indirect well HX.
Iron Fouling
Iron Fe2+ (Ferrous)					<0.2 ppm (Ferrous)
(Bacterial Iron Potential)	All	N/A	If Fe2+ (ferrous) >0.2 ppm with pH 6 - 8, O2<5 ppm check for
					iron bacteria.
Iron Fouling	All	N/A			<0.5 ppm of Oxygen
			Above this level deposition will occur.
Corrosion Prevention††
pH	All	6 - 8.5		6 - 8.5
		Monitor/treat as needed.	Minimize steel pipe below 7 and no open tanks with pH <8.
Hydrogen Sulfide (H2S)					<0.5 ppm
	All	N/A	At H2S>0.2 ppm, avoid use of copper and cupronickel piping of HXs.
			Rotten egg smell appears at 0.5 ppm level.
			Copper alloy (bronze or brass) cast components are okay to <0.5 ppm.
Ammonia Ion as Hydrox-					<0.5 ppm
ide, Chloride, Nitrate and	All	N/A
Sulfate Compounds
Maximum Chloride Levels			Maximum allowable at maximum water temperature.
	Copper	N/A	50 F (10 C)		75 F (24 C)	100 F (38 C)
			<20 ppm		NR	NR
	Cupronickel	N/A	<150 ppm		NR	NR
	304 SS	N/A	<400 ppm		<250 ppm	<150 ppm
	316 SS	N/A	<1000 ppm		<550 ppm	<375 ppm
	Titanium	N/A	>1000 ppm		>550 ppm	>375 ppm
Erosion and Clogging
Particulate Size and		<10 ppm of particles and
Erosion		a maximum velocity of	<10 ppm (<1 ppm “sandfree” for reinjection) of particles and a maxi-
	All	6 fps.	mum velocity of 6 fps. Filtered for maximum 800 micron size. Any par-
		Filtered for maximum	ticulate that is not removed can potentially clog components.
		800 micron size.

LEGEND

HWG— Hot Water Generator

HX — Heat Exchanger

N/A — Design Limits Not Applicable Consid-

ering Recirculating Potable Water

NR — Application Not Recommended

SS— Stainless Steel

*Heat exchanger materials considered are copper, cupronickel, 304 SS (stainless steel), 316 SS, titanium.

†Closed recirculating system is identified by a closed pressurized piping system.

**Recirculating open wells should observe the open recirculating design considerations.

††If the concentration of these corrosives exceeds the maximum allowable level, then the potential for serious corrosion problems exists.

Sulfides in the water quickly oxidize when exposed to air, requir- ing that no agitation occur as the sample is taken. Unless tested immediately at the site, the sample will require stabilization with a few drops of one Molar zinc acetate solution, allowing accurate sulfide determination up to 24 hours after sampling. A low pH and high alkalinity cause system problems, even when both values are within ranges shown. The term pH refers to the acidity, basicity, or neutrality of the water supply. Below 7.0, the water is considered to be acidic. Above 7.0, water is considered to be basic. Neutral water contains a pH of 7.0.

To convert ppm to grains per gallon, divide by 17. Hardness in mg/l is equivalent to ppm.

UNIT LOAD PIPING — For applications with wide temper- ature variation such as heating/cooling coils:

•Use piping materials that are rated for the maximum tem- perature and pressure combination. This excludes PVC for most heating applications.

•Ensure load water flow in high temperature heating applications is at least 3.2 L/m per kW to improve perfor- mance and reduce nuisance high pressure faults.

•DO NOT employ plastic to metal threaded joints.

•Utilize a pressure tank and air separator vent system to equalize pressure and remove air.

•Employ an 800-micron particulate strainer in both load and source plumbing to protect the plate heat exchanger.

Swimming Pool Hot Tub Applications — Load heat ex- changer should be isolated with secondary heat exchanger constructed of anti-corrosion material in all chlorine/bromine fluid applications.

Potable Water Applications

•Load coax material should always be vented double walled for use in potable water systems.

•Ensure load water flow in high temperature heating applications is at least 3.2 L/m per kW to improve perfor- mance and reduce nuisance high pressure faults.

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