Fundamentals of water heating - Coggle Diagram
Fundamentals of water heating
Temperature Time to Scald
125° F 1 1/2 to 2 minutes
130° F About 30 seconds
135° F About 10 seconds
140° F Less than 5 seconds
145° F Less than 3 seconds
150° F About 1 1/2 seconds
155° F About 1 second
Water usage/ person/day
Toilets 132L Baths/showers 105L
Clothes washing 68L Faucets 49L
64% usage has hot water potential
Water expands - when boiled also when freezed
Hot water is more corrosive than cold
(steel + water + oxygen = rust)
rate of corrosion approximately doubles from 60c to 71c; and doubles again from 71c to 82° F.
pH Acidity vs Alkalinity
Normal W --6.0 to 8.0 pH
presence of two dissolved minerals -
calcium and magnesium.
Calcium and magnesium combine with bicarbonates, sulfates, chlorides, and
nitrates to form these salts.
Difficult to remove soap scum on tubs, showers,basins and faucet fixtures.
Reduced sudsing and cleaning capabilities of some soaps and detergents.
Scale build up around faucet fixtures and on the inside of a water heater
higher pH - alkaline sulfide || lower pH gaseous form (rotten egg” odor )
when sulfates are converted to sulfide by bacterial reduction ‘sulfate reducing bacteria’
At 0.3 parts per million, produce brown or red stains
on plumbing fixtures. Higher- metallic taste
0.05 parts per million, manganese can cause black staining
. Undissolved materials such as sand, clay, silt or suspended iron contribute to turbidity.
Odors & Taste
ANODE RODS AND CATHODIC PROTECTION
factors affecting water’s ability to corrode
Temperature speeds up the corrosive process
Electrical conductivity: More the minerals :more the conductivity
Amount of dissolved oxygen
Cathodic protection: Water heated will attract the current circutes
Sacrificed Anode Rod