Need advice recommendations on oil boiler control upgrades to stop waste

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New Hampshire 03307
Just bought a house/office that was built in 2005, boiler installed in 2005
I have 10,000 square feet of finished space with Hot Water Baseboard heat.
The heating equipment is:
Boiler -- weil mclain Ulitimate PFO-7, Beckett Oil Burner 1.20 80A nozzle
Control Is Honeywell L8151A -- (Not used for circulator pump control)
Zone -- 12 Heating zones, 1 hot Water zone, 2 TACO SR504 and 1 TACO 506
Hot water is indirect 60 gallon superstor and set for Priority on the TACO 506 control

I have noticed since moving in that the Boiler seems to run a lot for short duration.
Typically 3 minutes, sometimes as little as 30 seconds.
I believe this short cycling is wasting a lot of oil.

I discussed this with the service tech. same person who installed the boiler when house was built.
I find the boiler runs even when there is no calls for heat of hot water.
He said this operation is normal for this type of boiler and the boiler cannot be "cold started". He stated cold start boilers have problems and I will not have hot water if a cold started this boiler.

I have done some research and the L8151A was setup for Low Limit of 140 and high limit of 180 with a 10 differential. In my quest to reduce this short cycling behavior I changed Low Limit to its lowest point 110, and set differential to 20 (highest). This has helped some but the boiler still runs a lot even without calls for heats.

Since the circulators are controlled by the TACO controls when a call for heat is made the pump for that zone starts immediately, and the boiler is then controlled by the high limits of the L8151A.

Therefore I do not see why I cannot change this boiler to cold start.
Why do I need to keep the boiler hot?

The house that I moved from had a System 2000 boiler installed in 1989 with 30 gallon indirect tank this is a cold start system and I never had an issue for over 30 years. Never ran out of hot water, I serviced it myself for the last 10, I always found it easy to clean.

Based on my observations, I believe I am using approximately 300 gallons of oil a year maintaining this boiler in a warm start condition. The basement utility storage room where this boiler is located to 900 square feet and it typically is over 80 degrees in that room. I working on insulating all the exposed hot water pipes but I think the majority of the heat is from the top of the boiler. The stack of this boiler is always HOT, I am considering installing a Stack damper to stop the flow of heat up the chimney when the system is not running.

Since I am only controlling the boiler with the L8151A, I think this control is one of the issues.

I just need a very basic boiler high temp controller, any recommendations??

Would a stack damper save me some energy?
Is a stack damper worth it? or does it add more problems?

Would an upgrade to a triple pass boiler be worth it??

My oil/propane company is pushing new propane boilers since they are 96% efficient, I keep thinking yes BUT propane has less BTU's then oil and cost about the same per gallon.

I would appreciate any comments/advice, to gain the most efficiency for the least amount of $$

Thank you


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Peace valley missouri
Cast boiler can't have return water under 140° because of condensation and cold water shocking the boiler where this causes sections to crack. As for as the nozzle all are rated at 100 lb pressure the 1.20 nozzle is 168k btu's. Most are over pressurized up to 60lbs over which increases btu output. Boiler water temp controlled by outdoor reset would help minimum water temp would still be 140°. Separating dhw to a different heating system would be efficient keeping the storage room cooler and what ever is above it all summer. Without a flue gas analyzer and knowing what pressure the nozzle is is operating at have no idea how efficient the flame is. Does the boiler cycle in the coldest temperature?If

John Gayewski

In the Trades
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A mod con boiler would be thr most efficient. Don't cold start your boiler. It'll kill it.

Part of effeciancy is using the equipment you have for its longest life. I wouldn't personally care if I burnt more oil because thre alternative could be 10k to 20k for a revamped system. This depends on how long your planning to live in this house. You could potentially use this boiler ten to 20 years and not recoupe the difference in cost between a new system and a more efficient boiler.

Money better spent is with insulation, windows, doors, sealing, and an outdoor reset.
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