Run cycle length

Mitch_6

on its cycling rate? Can you down fire?

You always want to size so the system runs "almost" constantly at the design degree day.

mechanical devices work best when moving.

The more you stop and start the more in effect you are and also the more wear an tare.

Stack temps are another issue, to low and you have other problems.

Mitch S.

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thfurnitureguy_5

Run cycle

The goal is to further shorten the run time on my boiler. After adding 400' of main pipe insulation (this year) and reworking the main vents and the return piping(last year)The gain has been a 30 min reduction in run time over each cycle. This was largely from the pipe insulation, and main vents. Knowing that my boiler is oversized, there is no surprise that the system is now cycling on pressure toward the end of the cycle. With the pressuretrols set at minimum .05PSI the system reads 2psi at shut off. Would a vaporstat be a problem or an asset in this situation? What would be the desired settings

gerry gill

the vaporstat would

initiate the short cycling sooner..two stage gas firing is your answer if its a gas boiler.

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thfurnitureguy_5

oil

Burnham V905A oil fired. Where does the short cycle become a problem? On one side I am paying to build the pressure up tp 2 psi. On the other side Im sure there there us loss from starting and stopping the boiler. Anybody know which is worse? It cycles on and off 2 to 3 times during a cycle. off time about 2 min. on time about 5.min. after the initial 40 min run.

thfurnitureguy_5

Yes. at cleaning we went back to the 4.5GPH from the 4.0. At that time we had not installed the insulation and the run times were 1:20 with no pressure. I plan to go back to that setup after installing some more radiation. I wonder if doing a heatloss calc for the large room with the t-stat would be wise? This room controls the whole building. It also had many radiators removed. Up to now I have only guessed at what to put back. The room is even and warm but who is to know if it is right?

gerry gill

isn't there

a modulating burner for the oil fired world?

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jim_110

short cycle

If you have insulated 400' of main, assuming it's 2" pipe ( my guess it's larger),that would be the equivalent of removing approx 353 sq ft of radiation from your load.If you are planning on adding that amount of iron (radiators)back into the system , then once done return to 4 GPH nozzle and see if you balance out.

Steamhead (in transit)

I'd heatloss your whole building

and see how the installed radiation in each room relates to its heat loss. Then make everything pretty much even, i.e. similar percentage oversized, and the system will balance out.

If you can reduce the amount of radiation in overradiated rooms, that will be even better.

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thfurnitureguy_5

The showroom is the one room with the most changes and also is the room that lags behind in heating. More radiation in this t-stat room should give me a faster heatup/ quicker turnoff of the system. There is about a 7* overshoot in the apartments. I agree that the right way to do this is to do the heat loss calc. But the "shade tree fixit way" is to add radiators till the tennants start to complain. (Just kidding) You have no idea just how much better this thing heats over 2 years ago. The biggest diference was from the pipe insulation. I still need to add more Gortons. I need to cut a bigger space in the floor joists and head off a box so I can fit 9 of those boyz. The faster venting will also help speed heat to that front t-stat room.