Do I need a new Aquastat?


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Old 10-03-08, 05:36 PM
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Do I need a new Aquastat?

I have a Weil -McLain FCC gas model boiler with two zones valve.After the boiler failed to heat up the low level floor, i replaced consecutively the thermostat,the zone valve and just yesterday,the circulator pump .However, the problem still remains unsolved.I checked the power going to the pump from the Aquastat side and it registered a zero reading.I got the idea to jump the pump and i had it run and the return pipes became hot, and i had heat on the first floor. Meanwhile, the second floor doesn't have a heating problem.
Could the aquastat be faulty? I don't want to waste some money unnecessarily , if a new aquastat won't resolve the problem.
Any help or suggestions would be appreciated.
PS-I forgot to mention my current aquastat model is the Honeywell 8148J.
nick
 
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Old 10-03-08, 06:00 PM
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if you jumped the aquastat to run the pump then the stat is NG.if not, jump it and see what cycles i always thought the zone calls the pump in thru an end switch and the aquastat maintains the boiler water temp during the heating call.
 
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Old 10-03-08, 07:02 PM
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Do I need a new Aquastat?

I did not jump the aquastat,rather i disconnected the 2 wires from the pump that were connected to the aquastat and jumped them.Then the pump ran and i had heat downstairs.
By the way, the boiler has no problem fired up. If i activate the thermostat for the lower floor the boiler would fire up ,except i won't get any heat.That is not the case for the upper floor.Upstairs would heat up right away.
 
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Old 10-04-08, 05:48 AM
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your circ pump should be controlled by the end switch within the zone valve,and the aquastat is totally dedicated to the temperature of the boiler water.if the aquastat is controlling the circ pump,and the boiler makes temperature 160F setting during a heating run it would go shut off even with the zones still calling.if you have a second pair of wires on the zone actuator they should control the circ pump relay,but not the actual pump wires to much of a load maybe thats why they have it thru the aquastat?like to here your final fix on this one.
 
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Old 10-04-08, 08:43 AM
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Do I need a new Aquastat?

Sminker ,your explanation makes lot senses.Perhaps, i should double check the wiring on the zone valve.The fact that i have heat in the upper floor makes me believe that the pump is working.At the beginning i did not think the zone valve could be related to the problem.Since the boiler would fire up ,once i activate the thermostat.Anyway,as i stated above ,i'm going to check the wiring on the valve and i will get back to you.
 
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Old 10-04-08, 11:38 AM
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your boiler doesn't maintain the temp within itself during the OFF cycle(closed zone/off circ) COLD START.you have to have a circulator relay so either zone end switch can call it on when it swings open,and with that the aquastat is activated to make its setpoint and cycle the gas burner off.you probably have noticed that the zone can be heating and the circ.is ON but the burner is off .that tells you the aquastat has made its limit......and waitng for the loop to come back cooler so it can come back on.
 
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Old 10-04-08, 06:22 PM
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Do I need a new Aquastat?

Based on your explanation, i ruled out the circulator as a culprit .I did also double check the end switch connection on the valve.Everything is ok. For ,when i activate the thermostat the boiler fires up.Although the valve was recently replaced, i suspect it might be the problem.Perhaps,i caused some damage to it while i was sweating the pipe.Just an assumption.I cannot thing of anything else.

By the way,what the right procedure to bleed the air out of the system? Some people recommend to shut off the boiler ,manually open one valve at a time with the water feed valve open.Other suggest to turn off the water feed valve.Which method is the correct one? i would like to bleed the system once more,hoping to get some result by doing so.
 
 

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