Aqua-stat temp reading versus boiler thermostat reading vary?


Old 12-06-15, 08:04 AM
biketrax's Avatar
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Aqua-stat temp reading versus boiler thermostat reading vary?

So I installed a high low Honeywell aqua-stat a couple of months ago on the home boiler. Set it to 160 low -180 high. (used to have a cold start) it has a digital reading (which I assume it being new and accurate). The analog thermostat on the boiler is reading almost 20 less.
Do I need to replace the old one? Or can it be adjusted or is it different locations on the unit that may be prompting this?
Any advise? thx
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Old 12-06-15, 01:45 PM
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It is very likely that the thermometer on the boiler is incorrect.
There is no way to adjust it I know of.... just replace it.
Old 12-06-15, 05:54 PM
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Replacing the thermometer may not change the reading. Placement in the boiler can make a big difference in readings and depends when you read it. Did you replace the aquastat well when you replaced the control?
Why did you switch to a less efficient operation by going from cold start to maintaining temperature? Heating a boiler with low water volume as cast iron and steel boilers have been for the last two decades and not moving water drops the efficiency when firing to maintain temperature and standby losses dramatically increase. There is also a chance of shortening boiler life by returning cool water to a hot boiler, turning off the pump, heat the boiler up, turn on the pump, return cool water to the boiler and turn off the pump, heat boiler up and turn on the pump, return cool water and turn the pump off. This continues until the water returns warm. More stress on the iron and more pump cycles shortens pump life.

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