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PLUMBING TOPICS CHIMNEY INSPECTION DIAGNOSIS REPAIR Clogged Piping & Hot Water Flow HOT WATER HEATERS HOT WATER IMPROVEMENT OIL & GAS PIPING GAS PIPING, VALVES, CONTROLS ODORS IN WATER OIL TANKS SEPTIC SYSTEMS SUMP PUMPS GUIDE TANK TYPES: WATER, OIL, EXPANSION, ALL TANKLESS COILS TOILET OVERFLOW EMERGENCY MIXING VALVES RANGE BOILERS RELIEF VALVES - TP Valves TANKLESS COILS WATER HEATERS WATER PRESSURE LOSS WATER PUMPS & TANKS WATER SUPPLY & DRAIN PIPING WATER TANK TYPES WATER TESTS, CONTAMINANTS, TREATMENT WATER, WELLS, WATER TANKS: TESTING GUIDE WATER PRESSURE LOSS DIAGNOSIS GUIDE WATER PRESSURE & FLOW MEASUREMENT WATER PUMPS & TANKS WATER PUMP & WATER TANK REPAIRS WATER PUMP PRESSURE CONTROL ADJUSTMENT WATER PRESSURE LOSS DIAGNOSIS GUIDE WATER PRESSURE & FLOW MEASUREMENT WATER TANKS HOW THEY WORK WATER TANK LIFE EXPECTANCY WATER TANK PRESSURE CALCS WATER TANK REPAIRS WELLS CISTERNS & SPRINGS Basement Wells Cisterns Drilled Wells - steel casings Driven Point Wells How Much Water is In the Well? How to Test Well Water Quantity How to Get More Water From a Well Hand Dug Wells Springs as Water Supply Well Pits WATER PRESSURE LOSS WATER TANK TYPES WELL CLEARANCES US-HUD/FHA WELL CLEARANCES US-EPA WELL CLEARANCES WELL LIFE EXPECTANCY WELL PIPING CHECK VALVES WELL PIPING FOOT VALVES WELL PUMP TYPES & LIFE EXPECTANCY WELL PUMP PRIMING PROCEDURE WELL CHLORINATION SHOCKING PROCEDURE InspectAPedia Blog - News Updates Air Conditioning & Heat Pumps Bookstore Electrical Environment Exteriors Heating Home Inspection Insulate Ventilate Interiors Mold Inspect/Test Plumbing Water Septic Roofing Structure Accuracy & Bias Pledge Contact Us |
This article describes water tanks and other kinds of tanks found in buildings, captive air and traditional water storage tanks or water pressure tanks, and we provide
advice about what to do when things go wrong, such as finding air and water leaks or deciding to replace a water tank.
Readers of this document should also see © 2009 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website. Various types of tanks uses in and around buildings are identified and explained below, including water pressure tanks, water storage tanks, range boilers for hot water, indirect fired hot water tanks, expansion tanks in attics, basements, and on heating boilers, oil storage tanks, rooftop tanks, cisterns, water pressure booster systems. We also discuss when to replace water tanks. Types of residential water tanksCAPTIVE AIR TANKS bladder-type water tanks for Building Water Pressure Regulation
Loss of air in "captive air" bladder type water pressure or water storage tanksIf a "captive air" or internal "bladder" (usually rubber) type tank is installed, and if the pump is short-cycling on and off, you should turn off the pump and call a plumber. We would suspect that the bladder has ruptured, or that the tank itself has developed a leak. We explain waterlogged water tanks and water pump short cycling in detail at WATER TANK REPAIRS where we also explain how to correct these conditions.
The newer type "captive air" tanks, one which use an internal bladder to contain the water separately from the air charge, can also fail. The bladder can rupture as we discussed above - you need a new tank. The tank itself can develop an air leak - you need a new tank. But these failures occur less often than with the older single chamber steel water pressure tank, largely because the tank bladder holding the water supply protects the tank interior from corrosion. On some captive air water tanks this design is reversed. For example on the WellMate™ water tank the water is in the tank and air is in the tank bladder. This difference can confuse the burst water tank bladder diagnosis procedure which we describe below. At WellMate Diagnosis we provide separate water tank diagnosis and repair advice. If the captive air water pressure tank bladder is ruptured, the air charge in the tank becomes lost over time and the tank acts like a water-logged steel tank discussed below. If the captive air water pressure tank bladder is collapsed,, defective, jammed, and stuck on itself it may not accept much volume of water, also leading to a short draw-down cycle before the pump has to turn on again. This is an unusual case but has been reported to me on occasion. Bladderless Fiberglass Water Pressure Tanks, such as the WellMate traditional hydro-pneumatic water tank operate similar to the steel water pressure tank, that is, no internal bladder is used to maintain and separate the tank's air charge and water charge pressure. These tanks incorporate a tank-top mounted air volume control and offer the advantage (over steel water tanks) of no risk of rust perforation and leak at the water tank. At WellMate Diagnosis we provide separate water tank diagnosis and repair advice for this water tank type. OLDER STEEL TANKS - Bladder-less Traditional Steel Water Pressure & Water Storage TanksThere may be lots of kinds of tanks found in buildings, storing water, fuel, hot water, or serving other purposes. We review quite a few of them here and include photographs to help you figure out what's what. Steel Water Storage/Pressure Tanks
The water storage tank in the photographs above is leaking, having rusted through from inside the tank. (This tank is less needed for storage than to smooth or regulate the water pressure in the building as the pump cycles on and off) Leaks like the ones in these photos can also leak the air charge out of the upper portion of the tank when the in-tank water level is below the leak point. So you might trace a water pump short cycling problem to an air loss in the tank to a leak in the tank itself.
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Range boilers are vertical or horizontal hot water systems whose water is heated by circulating the water from within a water storage tank (the range boiler) through a heat exchanger which is inside or connected to the exterior of a heating boiler. The water in the hot water tank range boiler is heated by circulating its water through the heat exchanger which itself is heated by the water inside or from the heating boiler.
The sketch illustrates how a very early type of coal-fired water heater range boiler worked. As homeowners shifted fuels from coal to oil or gas and installed central heating boilers, often the range boiler water heater was adapted to work with these systems as well, as you can see in the photograph.
As with the indirect-fired boiler described next, range boiler water heating tanks are usually located close to the heating boiler and will have both cold and hot water lines leaving the tank to supply the building with domestic hot water and a loop of piping that runs between the bottom of the hot water tank and a nearby heating boiler. Follow the pipes to see which pipes are performing which function. Our photo shows a silver steel range boiler hiding back in the corner behind the newer (though pretty old) gas fired water heater. (Notice also the efflorescence on the masonry block foundation, where the downspout has been spilling by the house foundation?)
See WATER HEATERS for details about residential hot water systems.
The difference between a range boiler and an indirect fired water heater is in the details. The heat exchanger that heats water in the range boiler is in or at the heating boiler. The water in an indirect fired water heater such as the SuperStorTM unit is heated by a finned copper coil located inside the hot water tank. The internal coil is in turn heated by circulating water inside the coil to and from the heating boiler. The range boiler is an old concept in use for about 100 years. Indirect fired water heaters are a modern system and are in current sales and use.
See WATER HEATERS for details about residential hot water systems.
This is a typical indoor oil storage tank in a residential building. We have a lot to say about oil tanks in buildings, oil tank leaks, environmental risks, potential costly cleanups, and effects of oil tank problems on the heating system and its operation. For information about oil tank issues and solutions see Heating Oil Underground & Above ground Oil Storage Tank Leaks, Testing, Problems & Solutions, Home Buyer's / Home Owner's Guide. These online articles answer most questions about above ground or buried oil storage tanks. What's really important in this photo is the black wall-mounted gauge our client is pointing to. He's found an indication that there is or was a buried underground oil tank at this property - potentially a costly environmental problem if that tank leaked. Given the leakage all over the old oil tank that we can see indoors in this photo, we weren't too optimistic about what might have happened with an old outdoor buried tank. Some testing was ordered. |
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Very large water storage tanks, such as the one whose end is visible in these photographs from two different properties, are likely to indicate that the flow rate of the well serving the property is very slow, even inadequate by contemporary standards.
We've found these old steel tanks at older properties in the Northeastern U.S. in situations where the well flow rate, the rate in gallons per minute at which the well can give water over a sustained period, to be very low, perhaps around one gallon per minute or less. Very low well flow or well water delivery rates in the 2.5 gpm range or below, simply can't keep up with the rate of water usage in a building during normal occupancy.
Worse, if we have only a typical water tank installed, say a 30 or 40-gallon unit, that tank is designed to smooth the flow of delivery of water to the building as the pump is turned on and off. A small water tank is not sized to actually store a reservoir of water for the building. So if our well flow rate is very low, the building will simply run out of water and occupants will have to wait, perhaps hours, for the pump to re-fill the water tank.
So a common solution for a low-flow-rate well is the installation of a very large water reservoir. At older properties the single water tank may have been 1000 gallons or even more. With a large water tank installed to provide this water storage reservoir, the well flow rate can be terrible but the building occupants won't see its effect since they're working off of the water storage tank.
At a low-flow-rate well installation the pump will be designed to run at a slow pumping rate so that the well water flow-rate can keep up with the pump as the pump sends water to the water storage tank. The building occupants use water out of the tank and the tank and well and pump recover their water slowly, perhaps overnight.
At newer properties this same approach may be taken to "solve" a low-flow well but instead of a single huge steel tank such as the one in this photograph, the plumber will install a series or cascade of from two to perhaps four or five smaller water storage tanks of perhaps 50 gallons each. If you are looking at a property and see that it has five new shiny blue and pretty big water tanks lined up in the basement you can guess that the well is marginal in its delivery capacity.
A final warning about low-flow rate wells: because in many areas water is flowing into the well through cracks in rock below the surface, and because we're starting with an already low recovery rate well, the future ability of the well to give water at all must be questioned. If local water is heavy in minerals, for example, the minerals tend to clog up those rock cracks over time, gradually reducing the water flow-rate into the well still further, until eventually it just stops working.
So a very large water storage capacity at a property is an indicator of both a low-flow-rate well (poor well recovery rate means the same thing), and an indicator that the future usability of the well at all must be questioned. We explain how people determine the necessary water tank size and volume at WATER TANK SIZE & VOLUME .
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The rooftop water storage tanks in this photograph from San Miguel de Allende in Guanajuato are being used both to accumulate a water reservoir so that water is always available to the building, and to supply water at a useful pressure. On low buildings or where the water tank is not high above the point of use, some systems install a water pressure booster pump and tank. We discuss water pressure booster pump and tank systems at |
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At some locations there is an up-hill or rooftop water source which is fed into the building entirely by gravity. The open top water tank in these photos used a simple float valve to let water into this storage tank. Where such intermediate storage tanks, perhaps fed by an uphill spring, were located in the upper floors of a building they fed water to building piping where it could flow by gravity when a water tap was opened.
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Basement & Outdoor Cisterns, are often located in the basement or courtyard of buildings where they collect rainwater for future use. In the U.S. cisterns were often located in the basement of a (pre-1900) home.
In arid areas such as the U.S. Southwest and parts of Mexico, very large cisterns are often placed in a courtyard where they collect rainwater for use during the dry season. This cistern is located in the basement of a pre-1900 home in New York. Later owners broke open a passage into the basement cistern and now use it for storage. This cistern was originally filled by downspouts directing roof runoff into the basement.
In a seasonally damp climate such as New York, an in-use basement cistern would certainly be a likely source of unwanted building moisture and would thus be a risk for problematic mold growth.
Cisterns in basements or attics are an open-type water storage reservoir found indoors, and are discussed further at Cisterns. A cistern was generally placed where it could be fed by gravity from roof or surface runoff, but any indoor open topped reservoir of water could be called a cistern. Attic Cisterns or water tanks are installed in some buildings to perform the same function as rooftop-mounted water tanks. Other smaller attic containers that look like a water reservoir may have been just an expansion tank for the heating boiler system. |
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Water pressure booster pumps and tanks may be installed in buildings where municipal water is supplied,
located on rooftops or anywhere in a building, so
don't assume that just because you see a pump and tank that the building is served
by a private well. |
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Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.
PLUMBING TOPICS
CHIMNEY INSPECTION DIAGNOSIS REPAIR
Clogged Piping & Hot Water Flow
HOT WATER HEATERS
HOT WATER IMPROVEMENT
OIL & GAS PIPING
GAS PIPING, VALVES, CONTROLS
ODORS IN WATER
OIL TANKS
SEPTIC SYSTEMS
SUMP PUMPS GUIDE
TANK TYPES: WATER, OIL, EXPANSION, ALL
TANKLESS COILS
TOILET OVERFLOW EMERGENCY
MIXING VALVES
RANGE BOILERS
RELIEF VALVES - TP Valves
TANKLESS COILS
WATER HEATERS
WATER PRESSURE LOSS
WATER PUMPS & TANKS
WATER SUPPLY & DRAIN PIPING
WATER TANK TYPES
WATER TESTS, CONTAMINANTS, TREATMENT
WATER, WELLS, WATER TANKS: TESTING GUIDE
WATER PRESSURE LOSS DIAGNOSIS GUIDE
WATER PRESSURE & FLOW MEASUREMENT
WATER PUMPS & TANKS
WATER PUMP & WATER TANK REPAIRS
WATER PUMP PRESSURE CONTROL ADJUSTMENT
WATER PRESSURE LOSS DIAGNOSIS GUIDE
WATER PRESSURE & FLOW MEASUREMENT
WATER TANKS HOW THEY WORK
WATER TANK LIFE EXPECTANCY
WATER TANK PRESSURE CALCS
WATER TANK REPAIRS
WELLS CISTERNS & SPRINGS
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11/03/2009 - 09/25/2000 - InspectAPedia.com/water/WaterTankTypes.htm - © 2009 - 1988 Copyright Daniel Friedman All Rights Reserved - InspectAPedia® is a Registered U.S. Trademark