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Erratic Hot Water

I have a home built in 1918 with oil fired hot water heat. It does not have a separate hot water heater - hot water comes off of the boiler. During the summer the hot water was more than sufficient. Since the colder weather has arrived, the water coming out of the taps varies from cool to warm to hot. The oil contractor bled the radiators but that did not fix the problem. This is our first winter here so don't know if this problem occurred in the past. Any thoughts will be greatly appreciated.

Re: Erratic Hot Water

Could you state your general location, and if you have hard water or soft water.

Hard water has a lot of minerals in it that over time can coat the inside of the HW coil inside the boiler.

This will lessen the amount of HW you get.

Did the oil person adjust the low limit HW temperature on the aquastat when he was there???

The low limit temp that controls the boiler water temp is ordinarily set at 140 degrees; it might help a little if the low limit was set to, say 160 degrees.

This would cause you to burn a few more gallons of oil, but you would avoid the expense of putting in a new coil (~$400 including labor).

These domestic coils have never been adequate to heat all the HW needs of a family, especially a family of more than 2 people.

Strongly recommended is an INDIRECT HOT WATER HEATER.

These are 30-40 gallon heavily insulated stand-aside units that don't need a separate burner or flue, as they run off the HW from the boiler via a zone valve or zone circulator.

The cost is ~$600 plus installation, but they are trouble-free & you'll never run out of HW.

Recommended brands are Triangle Tube III, Crown Megastor, Weil-McLain, Buderus, Burnham.

Re: Erratic Hot Water

Central NJ. Not sure on hard or soft water. The rest of what you wrote seems very helpful. Gives me something to run by the oil company. Thanks.

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