Carrier 50VS Water Quality Guidelines, Condition Closed Open Loop and Recirculating Well

In areas with extremely hard water, the owner should be in- formed that the heat exchanger may require additional system maintenance and occasional acid flushing.

Water Supply and Quality — Check water supply. Water sup- ply should be plentiful and of good quality. See Table 3 for wa- ter quality guidelines.

IMPORTANT: Failure to comply with the above required water quality and quantity limitations and the closed- system application design requirements may cause damage to the tube-in-tube heat exchanger. This damage is not the responsibility of the manufacturer.

In all applications, the quality of the water circulated through the heat exchanger must fall within the ranges listed in the Water Quality Guidelines table. Consult a local water treat- ment firm, independent testing facility, or local water authority for specific recommendations to maintain water quality within the published limits.

		Table 3 — 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	All	N/A			–0.5 to +0.5
				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)	All	N/A			<0.2 ppm (Ferrous)
			If Fe2+ (ferrous) >0.2 ppm with pH 6 - 8, O2<5 ppm check for iron
(Bacterial Iron Potential)
					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.
					<0.5 ppm
Hydrogen Sulfide (H2S)	All	N/A	At H2S>0.2 ppm, avoid use of copper and cupronickel piping or 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 allowable at maximum water temperature.
	Copper	N/A	50 F (10 C)		75 F (24 C)	100 F (38 C)
Maximum Chloride Levels			<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	<10 ppm (<1 ppm “sandfree” for reinjection) of particles and a maxi-
	All	a maximum velocity of	mum velocity of 6 fps. Filtered for maximum 800 micron size. Any par-
Erosion		6 fps. Filtered for maxi-
			ticulate that is not removed can potentially clog components.
		mum 800 micron size.
			Use cupronickel heat exchanger when concentrations of calcium or
Brackish	All	N/A	sodium chloride are greater than 125 ppm are present. (Seawater is
			approximately 25,000 ppm.)

LEGEND

HWG — Hot Water Generator

HX — Heat Exchanger

N/A — Design Limits Not Applicable Considering 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, basic- ity, or neutrality of the water supply. Below 7.0, the water is con- sidered 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.

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