problem with triple aquastat

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Old 08-23-13, 04:05 AM
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Question problem with triple aquastat

Just finished plumbing in an OWB to my existing heating system. I am now testing and tuning the system getting all air out and making sure I am ready to go come heating season. Ran into an issue when firing up the main circulator on the existing boiler in the house. Thermostat operates properly. Taco zone control operates the zone valves and the zone valve operates after thermostats call for heat. Contactor/relay on triple aquatstat "clicks". Terminals for the circulator are not getting power. Am I missing something or did the aquastat crap out?

Dave
 
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Old 08-23-13, 07:58 AM
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Could be just a wiring issue. Where do you have the pump connected to???? C1/C2.

Whats the hi/lo/diff set to?

Zone control to TT correct?
 
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Old 08-23-13, 08:57 AM
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Contactor/relay on triple aquatstat "clicks". Terminals for the circulator are not getting power.
This could be normal operation for a triple aquastat.

With a triple, the circulator is disabled by the control until the boiler reaches it's LOW + DIFF setpoint.

Example: If your LOW is set at say 140 and your DIFF at say 15, the circulator will not run until the boiler temp reaches 145.

The operation of the LOW and DIFF on a triple is not really easy to understand...

The LOW setting in a triple has a FIXED NEGATIVE 10 DIFF. This means that regardless of the setting on the DIFF dial, if you are set at 140 on the LOW, the burner will always fire when the boiler drops below 130 which is the LOW MINUS the fixed diff.

The ADJUSTABLE DIFF ADDS to the FIXED -10 DIFF.

In the above example, this means: ( LOW MINUS 10 ) PLUS DIFF ... or (140 - 10) + 15 = 145

So, bottom line...

Run the boiler until the water reaches the temp at which the circ will be enabled. To cause the circ to be enabled sooner, temporarily turn the LOW and DIFF to their lowest settings.

It is a good idea when refilling the system to get the water good and HOT (180) anyway... in order to drive out the majority of the air that came with all the new fresh water you added after refilling.
 
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Old 08-23-13, 08:58 AM
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Let me ask this:

Why are you running a triple aquastat?

Does your boiler supply domestic hot water to the home via a 'tankless coil' installed inside the boiler?
 
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Old 08-25-13, 05:48 PM
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Red face problem solved thanks to your help!

You guys have just saved me from buying a new aquastat! I was attempting to run my circulator with a cold boiler to remove air from the system and make sure all my new installed components worked properly. Fired the boiler up tonight and.....a circulator will only run when the temp of the boiler hits my low set point. Circulator is fine, air is out and now I'm waiting for old man winter to drop the temp so I can fire up my outdoor wood boiler. Thanks for your help!!!!
 
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Old 08-25-13, 07:47 PM
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Glad ya got it figured out...

air is out
Ha ha! That's what YOU think! :NO NO NO:

What you are going to find is that once you start the heating season, TONS more air will magically appear in your system. All that dissolved air that was in the fresh water you added will be driven out of the water when heated...

Be prepared to bleed some more... and again... for the first month or so.
 
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