Aquastat Replacement for L8148A?

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  #1  
Old 03-18-14, 03:01 PM
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Aquastat Replacement for L8148A?

Hi Folks,

Our boiler has had a trip to the spa lately.

Was getting delayed light-off earlier this winter, so we replaced the ignition transformer with the new electronic variety and now it lights-off perfectly. Next I was getting intermittent lock-outs for no reason...would just lock out while running perfectly at 500ohms. So I changed the original red-button primary to the new electronic primary controller...problem solved.

To complete the spa treatment, I'm planning to change the aquastat. In an old post, I described how it failed at the relay solder joints (a common problem I guess). I repaired it first by adding a jumper around the failed trace. That worked for 4 years and then another joint failed, and that one was a simple re-solder. So its working fine now, but failed twice so I'm thinking I should change it.

Question is do I get an original L8148A, or swap out with an electronic L7224U?

Our boiler is a bit oversized for our house. I think it short-cycles...I timed a few heat calls and the burner runs about 2 1/2-3min per cycle for a zone heat call (regular baseboards). That seems low to me. I've tried downfiring from 1.0GPH to 0.85GPH and that helps a little.

The one thing that I think might be a good feature of the L7224U is the adjustable limits. We could set it for a wider differential and let the burner run longer with fewer cycles.

Has anyone had experience using a L7224U to improve short cycling performance? Any other features that come in handy?
 
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  #2  
Old 03-19-14, 11:27 AM
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I am not an expert. But you might want to consider one of these Aquastat's.

48-3250 - Hydrolevel 48-3250 - Model 3250 Fuel Smart Hydrostat (Temperature Limit, LWCO, & Boiler Reset Control) for Oil Boilers


7600A0001U - Beckett 7600A0001U - AquaSmart Boiler Temperature Control (120 Vac) - Oil with Temperature ONLY Sensor


It seems like they may give more control over adjustments which might help with your short cycling.
 
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Old 03-19-14, 01:05 PM
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Dean100,

Thanks for the other options. Actually it never occurred to me to look beyond Honeywell. The Hydrolevel unit looks interesting with its heat call monitoring algorithm.

Are there other options people know of? Does anyone have an aquastat that monitors and logs burner-on time?

Between fiddling with temperature limit settings and looking at down firing the nozzle, I hope to see longer run times per cycle but lower total run time per day. Would be nice to collect this data to inform improvements.

Thanks again!
 
  #4  
Old 03-19-14, 03:50 PM
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aquastat

I'll vote for the Hydrostat 3250. I installed mine 2 years ago and I love it.
Steve
 
  #5  
Old 03-20-14, 08:24 AM
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Hydrolevel vs. Beckett Boiler Controls?

Thanks Sdodder...good advice...I'm leaning that way also.

Reading back through threads on this, people seem to prefer the reset algorithm on the Hydrolevel 3250. It looks like a nice unit that would fit my needs well.

Does anyone have thoughts either way? If you had to choose between a Hydrolevel 3250 and a Beckett 7600, which would you pick and why?
 
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Old 03-22-14, 12:31 PM
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Hydrolevel 3250 vs. Beckett 7600

Does anyone have an opinion on Hydrolevel 3250 vs. Beckett 7600?
 
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Old 03-22-14, 04:06 PM
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Given my druthers, I would go with the 3250.
 
  #8  
Old 03-24-14, 08:50 AM
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3250 It Is...But What About Wood Heat?

Thanks for the advice...will go with the Hydrolevel 3250.

But...

We heat with a wood stove in our living room for say 70% of our heating needs. So the thermostat behavior will not be a good way to sense heat load needs...unless we have an extended period without wood heat, but that is rare in the winter.

We also have an indirect hot water tank in the system. I'd like to use the Hydrolevel unit to reduce the water temperature circulating through the heat exchanger coil. It is a 70Gal tank (we have a large tub, but I regret buying such a large tank), so we never run out of hot water. Trouble is its costing us a fortune for DHW.

So I'm inclined to not use the Boiler Reset feature, since it will probably not be accurate, and won't save much anyway since we don't use a lot of oil for heat. One option is to use the outdoor temp sensor...that would help with accuracy.

Main goal of this unit is to address short-cycling. I'm hoping to increase the burn time by 2 or 3X (currently 2.5-3min cycles) by a combination of increasing boiler differential range, and reducing nozzle size.

Thanks for all the input!
 
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