Boiler replacement with hot water tank


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Old 02-19-23, 01:51 PM
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Boiler replacement with hot water tank

I have a 70 year old hot water boiler that I would like to replace with a gas hot water tank. Is it possible?
tnx Ron
 
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Old 02-19-23, 08:21 PM
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Yes it is possible but what is reason to replace it? They have no established life span.

Simple low cost things make DH 1957 boiler 86% efficient. With two big doors, is easy clean and maintain efficiency. New boilers are difficult to clean and so loose efficiency.

Steel, gas hot water tank boilers have short life span. DH replaced his 50 gallon oil fired tank water heater after 20 years. New gas fired is less efficient, fire it only in summer.

New boilers have shorter life span and on old (not radiant element) systems run low efficiency, Not high.
 

Last edited by doughess; 02-19-23 at 08:45 PM.
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Old 02-22-23, 04:54 AM
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I am not quite sure what you mean by a hot water tank. A new boiler, or just how you make your hot water?
Either one is yes, the new boilers are cold start so they only run when needed. The flue passages are much smaller to increase thermal transfer. More of the hot flue gasses touching the surface area of the heat exchanger and much less water volume.
There are two types of efficiencies combustion and thermal. The first is how efficiently the flame is burning, the second is the thermal transfer of heat to the metal and water.
 
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Old 02-22-23, 06:35 AM
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What are you trying to do?

1. Replacing the forced hot water boiler for home heating (space heating) and installing a separate tank water heater for domestic (faucet) hot water?

2. Keeping the existing FHW boiler for home heating and installing a tank water heater for domestic HW?

3. Replacing the boiler with a(n electric) heat pump (requires pre-existing, or must become, central AC) and installing a separate water heater for domestic HW?

4. Other, describe.
 

Last edited by AllanJ; 02-22-23 at 06:54 AM.
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Old 02-22-23, 12:55 PM
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Or do you mean,

5. Replacing the FHW boiler, lock stock and barrel, with an ordinary gas tank style water heater?

This has been done before in a small house. An ordinary gas hot water tank is fundamentally and topologically the same thing as a gas hydronic boiler. But one unit cannot serve both functions because the same body of water (its contents) may not supply both faucets (potable function) and radiators (non-potable function).
 
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Old 02-28-23, 07:05 PM
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Ordinary gas tank style water heaters, with center flue, are far less efficient than 84% boiler with same BTU rating. Home heating systems baseboards and radiators are designed to provided adequate heat with 180F water

Tanks are lower priced than boiler but fuel costs to heat home are very high.
Most have an Efficiency Factor (EF) of . 58-. 60. That means that 58-60% of the energy that is being used to heat your water is effectively converted into heat.

.
 

Last edited by doughess; 02-28-23 at 09:02 PM.
 

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