tankless HW coils

ken D

What is there to keep the water in a tankless HW coil from boiling in the pipes when the boiler is heating the heating hydronic loop? Say we don't use the domestic water for a while and the baseboard has a long load, why won't the water in the HW coil not boil, it's just sitting there.

ed wallace

tankless coil

1st of all the if its a hot water boiler it should not have a hi limit set above 180 degrees 2nd the coil is under street pressure to make steam you need 212 degrees

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ken D

so there might not be enough heat to heat the house if the tankless coil is the deciding factor? the heating water may not be heated hot enough in the time that it can run once that domestic hot water reaches 180*; the heating water is at domestics mercy? Are there 2 limits, one for the Tankless hot water and another for the boilers heating water?
You may have 160 or less return heating water, but the boiler cannot fire because the domestic is 180*? Or does this scenerio get factored into its size?

lchmb

ok

little confused by what you said but, the aquastat on a boiler is generally placed into the face of the coil. The coil loops around it in a circle. The aquastat senses the boiler water not the coil water. Generally a triple aquastat will keep the boiler at 160 degree's to maintain domestic water temperature. When their is a call for heat the aquastat will then take the boiler to high running temp (generally 180 degree's) so that it can make enough heat and also keep your domestic water warm. If the coil is starting to plug you will sometime notice a drop in domestic water when the house first call's for heat in the fall and spring....hope this makes sense..

Ken D.

H W

The water is under pressure. Water boils at 212 at atmospheric pressure and boils at increasingly higher temps. as press. goes up. So at 50 to 80 psi, the temp. needed to boil water is probably over 250 degrees.

Weezbo

it is\" Under Control\"

the tri aquastat monitors the water temps...now if it IS BOILING! turn the boiler Off! dont do anything fancy,pick up the telephone and call a service tech and state that the boiler may be in Low water condition and cannot determine if the idiot gage on your boiler is working correctly.....adding water thru a fast fill could be extremely disadvantageous to your health...and presence of,Well. being.