Cycling Question on Existing Oil-Fired Boiler

[Clarkbug]

Good Morning All.

I have been lurking around here for a few months, reading up what I can for options for installing a wood boiler for the house that my wife and I purchased earlier this year.

First, let me say that I know that this forum isnt really for oil-fired anything, but given the range of experience that I see here for controls, water storage, temp control, etc. I wanted to ask for some opinions. Mods, if this isnt OK, please just let me know.

Im heating a ~2700 SF farmhouse that was built somewhere in the 1890s or so. As far as I know, no insulation in the walls, just bricks. There is some blown cellulose in the attic, and most of my windows are single pane. The boiler is a two year old New Yorker oil fired unit with ~80% efficiency, and the nozzle thats in it now I believe is rated for 125,000 BTU/hr.

My actual question is in regards to the way the boiler operates. When there is a call for heat, one of my two zone circulators fires up, then the burner fires. It will run until the boiler hits its high limit of 200F, then sits until it cools to 180F. So for the most part, it just keeps cycling on and off until the zone is satisfied.

The heat is delivered to the space by baseboard fin tube, which is on pretty much every exterior wall. My thoughts are that I have a flow problem, or there is a control problem on the boiler itself.

Can anyone offer any insight?

Much thanks!

 

[DBoon]

How long does it take until it hits 200 degrees (upper limit)? On a very cold day (like now), I wouldn't think it would ever hit the upper limit.

My guess is that your pump is not turning on to circulate the water. This could be a bad switch or control of some sort, or a bad circulator pump. The boiler is operating in a convection circulation mode only, which gets some of the hot water to the radiators, but not fast enough. I had this problem with my oil boiler a few years ago, and your symptoms are pretty much the same as mine.

 

[Clarkbug]

It depends on if one or both of the zones is working, but typically its between 5 to 10 minutes. Longer if the house has been warm for the day and the sun is out, and the loop has had time to cool.

Both of the pumps are definitely energizing, as I can hear them running, and if I put my hands on them I can feel the mechanicals working. Also, the fin tube makes that popping/crunching noise as it comes up to temp, and it gets rather hot. I wouldnt assume this would be possible if the circulator wasnt running properly, but I could be mistaken.

 

[btuser]

Sounds like its working as designed. That's the way mine works, and the last 3 houses I owned.

Call for heat causes boiler to fire. Depending on your setup the circulator will fire simutaneously or wait till a design temp is reached.
Burner will fire untill high limit is reached, then fire again when low limit is reached and so on untill the call for heat is satisfied.

Is your question about the design temp? 200F is hot for all but the coldest days of the year. If you're interested in controls and maybe trying to sqeeze out some extra $$ from your heating dollars it can be done, but I would suggest caution. Depending on how you get your hot water it may not even be worth it for you. Have you got an indirect or tankless coil for hot water? The reason I ask is because if its a tankless your boiler will need to remain at a minimum temperature just to give you hot water, and the lower you go the less hot water you have available. You can add a booster tank, or go all the way with an indirect (which is what I did, I've been down the EXACT same road) but how easy its going to be and your final product is dependent on a lot of different things. My own experience was less than great, not so much because of the boiler but because I have many small zones, which is not good for modulating the boiler temp. I was constanly cleaning the firing tubes.

What model New Yorker is it? Steel or Cast iron? Single or 3 pass? Low mass vs Standard?
How long between firings? How long to go from 180f to 200F?

 

[steam man]

The boiler is doing pretty much what it is suppose to do. With only one zone calling for heat the boiler should cycle more as opposed to when everything is calling for heat. You can check the flow to each zone just by touching the pipe when the pump turns on. If it starts getting hot its fine as opposed to all the time. I am just wondering about the btu output of the baseboards in each zone, the flow rate, and the heat loss of the house. If your boiler is cycling a lot, too large a nozzle will do this, you may need to go to a smaller one so the boiler fires longer. It sounds to me the nozzle size is about right. I would maybe think about installing a heat manager to reduce the number of cycles. Most of all, get as much insulation installed as you can.

 

[btuser]

Count how many feet of baseboard you have on each zone. That will give you an idea what you need for water temp to heat your house on design days (and an idea how low you can go).

 

[Clarkbug]

Thank you for the replies all. Good to know that something isnt majorly wrong...

I guess I just wanted some confirmation that the system was working properly, as this is the first place I have lived with an oil burner in it. Prior to this I have heated with a woodstove, and most recently an OWB.

My setup has two circs, one for each zone of the house. A call for heat enables the circ pump, and then the boiler is enabled after that. I have an electric tank for hot water, so that wont factor into anything for me.

Ill have to time how long between cycles so I can give a reasonable answer. While Im doing that, Ill go pull the info on the boiler. All I know is that its a steel boiler, not cast iron. It has the smallest nozzle size in it right now, from what I was told by the previous owner.

Ultimately, my intention is to rebuild all of the single pane windows this summer, as time allows. Some need new glazing, some just need to be stripped and painted, but all need a heavy dose of weatherstripping, and I intend to build exterior storms as well. (Ambitious, I know) Based on my oil consumption so far this year (Figuring ~500 gallons or so) I am strongly considering installing a wood boiler, as the cost savings alone will pay back in just a few years. I had looked at going OWB, but by the time I purchase that, do a proper job with the buried piping, and then build a storage shed for the wood to keep it dry, I figure that it would be better to install an indoor gasifier and tie it in parallel with the oil burner. (Which is what really brought me to this site)

For now Ill get some info on the cycling of my boiler to see what its up to. I would really just like to maximize its efficiency to save on oil. (Over the last month, it averaged about 7.5 gallons per day, which at my prices was $25. Ugh.)

 

[willworkforwood]

Sounds like you are developing a good plan. One thing about gassers is their efficiency greatly depends on seasoned wood. So if you have wood (preferably already down) on your property, and the snow isn't too deep, you can get started right now getting it cut, split (small), and maybe stacked. Also (if you haven't already), you could tape 3-4 mill poly over the worst windows - looks ugly, but can save lots of $$. And since you're not doing DHW with the boiler, you can drop the hi and low limits a bit, once it starts getting warmer. Lots of work there - good luck with it!

 

[btuser]

An electric tank for hot water tells me you have a cold-start. At 7.5 gallons/day you're doing all right because that's still only around 45k btu/hr and your boiler is pushing close to 150k/hr. Have you got a stove running? 40k/hr for an old farmhouse is an awesome place to start.

 

[Clarkbug]

We are still putting up the "sticky windows" in the house, pretty much as fast as our cat decides to take them down.... Sigh.

I should mention that my house is 60F right now, and our upstairs is set at 46F. We are living in the downstairs for the winter as we still have some work to do on the floors upstairs, and didnt want to have to move in/out several times. Plus we pulled out an oil fired furnace that heats about 300 SF of the house, and thats going unheated for this winter.

The boiler is a New Yorker CLW-5-P-NB, with a Beckett R7184B burner, if that means anything. Its rated from 1.25 to 1.65 GPH of oil. According to a little card left here by the previous owner, he has installed a 1.25B nozzle, which should be 175,000 BTUH. (Which seems pretty close if you use 142,000 btuh per gallon of #2). The rating on the little energy star card stuck to the boiler says its 80% efficient.

Nope, no other stove going. There isnt a good place to put a stove in the upstairs of the house because of the travel path to bring wood in and out.

Also, looking at my control, I only see one dial for the limit, and Im guessing thats the high limit. I dont know where the adjustment would be to adjust the low point, or if its just a fixed 20 degree differential.