Is this short cycling??

pedmec

Only 5 convectors? any other radiation? I'm assuming they are all 3 rows.

What i got for EDR is 141.5 sq'. You can do other manufacturers but they will all be in the same ball park.

109A_5

" Do i let it short cycle or do I raise the pressure to cut back on the cycles? "

Pick your poison, IMO either of those options have negative issues. If it were my system I'd go with the delay timer. Although it may be a bit interesting to implement depending on how the hot water loop is controlled, since you don't want it to have a negative influence on it.

Jamie Hall

Let it short cycle. Raising the pressure will cut out on the cycling some… but… guess what? that extra oil you're burning whin it is not shutting off is pure wasted energy. And around here at least, energy costs money…

skimmer

@pedmec I have two more… baseboard steel pipe convectors with fins around them. These were the 3 row copper convectors that were removed in kitchen and bathroom by previous owner. These steel pipe convectors, bathroom one isnt that long maybe three feet, kitchen maybe 5..

I dont think they would add much to the EDR. thank you for taking the time

@109A_5 Im not sure what to do. I can play around with my tsat. cycle times even temp offset.

Heck I can manually lower the temp from my phone by 1 degree once the rads start heating to shut the boiler off, and restart again by upping it one degree. Sort of making my own longer steam cycle when I am home.

The hot water loop is on its own tstat and relay? It has its own aquastat and fires up the boiler independently when needed. Circulator pump runs on its own and circulator while the water is hot. Aquastat is at 180 with a 30 degree setback

bburd

If that were my house I would just not worry about the cycle rate. Keep the pressure low, under two psi max. Keep an eye on the vents and the water usage. Keep the pigtail and openings to the boiler and pressuretrol clean. If it's oil, have the burner cleaned and serviced at least every two years; if it's gas, watch for signs of abnormal combustion and have it looked at if you see any. Maintain good carbon monoxide detectors. You will be way ahead of most steam boiler owners.

ethicalpaul

most people won't even notice an oversized boiler, but they certainly will if it's undersized

And yet everyone who comes here has complaints caused by the boiler being oversized 🤔

bburd

https://forum.heatinghelp.com/discussion/comment/1832769#Comment_1832769

Many who come here are paying too much attention to their heating systems. For the average residential or small commercial steam heating system short cycling is a fact of life, a compromise driven by rules of thumb, on/off burners and the rule that "time is money".

ethicalpaul

Don't get me wrong, I don't hate so-called "short cycling" in steam. At least not in atmospheric boilers. It might not be great for oil burners, I'd have to ask @EdTheHeaterMan

But I think it's fair to say that the problem of oversized boilers is much larger than the problem of undersized boilers, which I honestly can't recall ever truly seeing.

109A_5

Well cycling the thermostat with a phone once or twice an hour 24 / 7, for me would get old in about an hour. Some thermostats may do it.

Depending on how the hot water loop control is wired into the original boiler wiring the pressuretrol may also disable the burner regardless of who is calling.

skimmer

I might go back to a pressuretrol let it run to 2 and cutback in at .5

I’m not sure if this will accomplish much

I still have to test with the tenant home and running the hot water loop first. I wonder if that would make a difference with the current set up

EdTheHeaterMan

https://forum.heatinghelp.com/discussion/comment/1832773#Comment_1832773

I Agree:

To paraphrase a great member of this amazing forum

But I think it's fair to say that the problem of oversized boilers is much larger boilers than the problem of undersized boilers that are much smaller, which I honestly can't recall ever truly seeing But I can't say that I have looked for them . On a rare occasion I may have falsely saw one. But I may have been mistaken.

ethicalpaul

funny Ed! But I was asking seriously, is short cycling bad on an oil burning boiler?

On my gas atmospheric it seems like nothing different than a short call for heat

Jamie Hall

I'll be interested in @EdTheHeaterMan 's take on this, too, @ethicalpaul . There are some parts which may be limited by the number of cycles — relays or microswitches, for example, are often rated by number of operations. The numbers tend to be rather high — but still there is a limit.

The other item for any power burner (oil or gas) is the blower motor. I have relatively little experience on those — but I do know from years gone by that when we were dealing a lot with submersible pumps we tried to size things — particularly the pressure tank — so that the worst case pump cycle was a 50/50 duty cycle with no more than 12 starts per hour. The people who made those things stated that that would do no harm. Wonder if the same applies to blower motors?

skimmer

well let’s see. I have gas. So there’s the gas valve, the damper switch and motor. Control board. The thermocouple. And I’m not sure what else. But how many cycles are these rated for?

My last burnham didn’t suffer any loss of components due to cycling

Jamie Hall

The least reliable component you mention, @skimmer , is the damper switch followed closely by the damper motor. They are notorious for short lifetimes… Neither the control board nor the thermocouple should be affected by cycles, but the control board can and will be affected by power spikes and the thermocouple may be hour limited, not cycle limited. The gas valve will probably outlive us all… maybe not. But consider how many cycles a modern automotive high pressure injector is expected to withstand! They operate at an average rate of around 1500 cycles per minute… for upwards of 3,000 hours!

EdTheHeaterMan

https://forum.heatinghelp.com/discussion/comment/1832825#Comment_1832825

I can never pass up a good play on words Paul

Regarding a short cycle on an oil burner (or gas power burner for that matter). The longer the operating cycle the better. The combustion efficiency of an oil burner does not reach its peak until the burner has operated for at least 2.5 minutes and can take as long as 5 minutes.  So if we take an average of about 3.5 minutes for a typical oil burner, if you only operate it for only 2 minutes, 100% of the operation time is something less than peak efficiency.   If you run the burner for only 4 minutes, then 80% of the operating cycle is at less than peak efficiency.   

This is based on information provided by the Bacharach combustion testing equipment people. Wary back when we all used the “Wet Kit” the instructions clearly stated the wail until the burner operated for 4 minutes before taking any combustion tests. 

Let's say the burner operates for 4 minutes then stops by the high limit then restarts after 2 minutes, then stops after 2 minutes for the rest of the heating cycle, while the circulator pumps the 180° water (or the steam pressure continues to fill the radiators), then your oil burner never really gets to the best operating efficiency. 

Grant it, the combustion chamber may only cool down a little during the off cycle, and when the burner restarts it is already up to 50% of the operating temperature on the successive cycles, the time to get to peak efficiency may be shorter, but the best operation of the oil burner combustion process will only happen after the burner is operating at steady state non-stop for over 10 minutes. If you have regular cycles less than 10 minutes by design (like over sizing or micro zoning). Then you have a system that is nowhere near the stated efficiency in the propaganda literature labeled A.F.U.E  

ethicalpaul

Thanks Ed!

Whereas my gas atmospheric is just a cast iron pot with passages in the middle that sits above a fire that is the same after two seconds or two hours, the best that I can tell (in fact, in my case, the efficiency must tend to go down as the burn time increases due to less heat being transferred to the cast iron due to reduced temperature differential).

Sorry for any hijacking that may have occurred