How to make Hydronic Hot Water System Hotter?


I have a potable hot water system that uses the third zone off of my furnace to heat a coil in a storage tank.
While the water is hot, it isn't hot enough for my liking.
Can someone give me a clue on how this system works, and what settings I should be looking for?
Thanks Peter
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Water tank stores heated water. When water tank temperature is low the tank sensor calls for circulation from the boiler. If the boiler temperature is too low the boiler temp sensor fires the boiler.
The water heater should have a temperature sensor inserted into the tank to turn the circulator on to bring heat into the tank coil. Might check the temperature setting there. There may also be a tempering valve on the outlet of the water heater tank to limit the hot water outlet temperature, check that setting.
Second if the incoming water to the coil from the boiler is too low you can't raise the hot water temperature above that. Check the boiler temperature gage and also determine if there is any tempering valve on the boiler feed to the water heater tank.
Finally, are you sure you want really hot water. There is a risk of scalding , especially with children and the elderly.

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El Penguini wrote:

That is known as indirect fired domestic hot water.
The first question is what is the delivered water temperature you are getting? It should not be above 130 degrees for safety.
The output of this indirect fired storage tank should have a tempering valve which mixes cold water in with the hot output of the tank to maintain this 130 degree limit. The tempering valve will have three connections and usually a black knob at one end which can be used to adjust the output temperature. This would be the first place to check, both the adjustment and the valve itself as they can go bad.
The indirect fired storage tank should have a temperature control on it that is used to request heat for it's "zone" when the tank temp is low. If there is a proper tempering valve on the tanks output then this control can be set fairly high, close to the boilers operating temp, if no tempering valve then this control has to be set to the 130 degree limit or lower.
If the actually boiler operating temp is lower than 130 degrees you likely have a problem there since that is abnormally low. 160 - 180 degrees is more typical for a boiler operating temp.
Summary: The indirect fired DHW tank operates as a heating zone from the main boiler. It has it's own thermostat which would be set between 130 and 180 degrees depending on whether there is a tempering valve on it's output. It should have a temperature gauge so you can see the current tank temp. If it is sufficiently hot and the delivered hot water temp is still too low, the tempering valve is suspect.
Pete C.
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Assuming the boiler temperature is set for 180 more or less, depending upon the brand of indirect you have, you will probably find its temperature adjustment on the top of the tank, or some will have a digital control low, on the side

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"Heating the Water The thermostat controls the temperature of the water inside the tank. Normally you can set the temperature between 120 and 180 degrees Fahrenheit (49 to 82 degrees Celsius). It is generally recommended that you keep the temperature between 120 to 140 degrees F (49 to 60 C) -- especially if there are children living in the house -- to prevent scalding. It also saves energy." and more at: http://home.howstuffworks.com/water-heater.htm/printable how your boiler works: http://home.howstuffworks.com/how-to-troubleshoot-a-hot-water-and-steam-distribution-system.htm/printable
usual definition clarification: furnace=heating of air boiler or hydronic =heating of water
lookup boiler manual online. look up any manuals online for any connected parts that control your devices. like honeywell. depending on what type of heating this is there will be everything with operating manuals or instructions and they will all need to work together. if the third zone is a forced air furnace, i don't know. if it is a boiler, it may be along for the ride as a passive loop with the system operating year round. if it has an active burner or heating element find its temperature control or zone control valve.
El Penguini wrote:

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