Triple Aquastat settings

Old 02-15-07, 11:54 AM
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Question Triple Aquastat settings

Mom called me to take a look at her furnace. She has had a new company for her service contract and oil supply the past year and we're not happy with the abilities of their service personell.
Mom complains that the furnace is running a lot more and taking a lot of time to heat the house and the lower floor (2 story) doesn't get hot like it used to.

I went to check the operation and found that when the burner came on, the circulating pump for the hot water to the radiators would only run for about 1 minute, go off and stay off while the burner would keep running 8 - 10 minutes.

I saw that the wire from the pump were fed from the Honeywell Triple Aquastat Relay Type L8124A, which was replaced at the end of last winter by a service technician.
The high was set at 180 degrees, the low was set at 170, the differential was on 15.
When the burner came back on I turned the Low down to 140 deg. and the circulating pump stayed on, so I set the Low at 130, the differential to 20 and checked the house for a couple of hours and the heat came up like the old days.
It's been a 2 days and the heat is fine but she says the water from the faucets isn't as hot as it used to be and she's running out of hot water in the shower faster. This furnace runs all year to supply hot water. Can someone tell me the proper settings. I'm definitely not sure of the differential. Thanks for your help.
Old 02-15-07, 12:19 PM
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Set the low to 160 and the diff to 15. The 180 & 170 settings were to close, and by setting the low at 130 the boiler won't be able to make enough hot water for the coil and it will probably be playing catch up if there is a heavy demand for heat.
Just my 2 cents worth!
Old 02-15-07, 06:16 PM
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Aquastat Settings

The settings as suggested by Michael are a good place to start. If you have to make further adjustments, always maintain at least a 20 spread between the Hi & Lo.

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