brin house

reds

recently installed a boiler once the old one expired and leaked all over. for years I have been addiing water weekly to the boiler and bypassing the auto feeder that seems to have problems. and weekly draining the lower drain to clear mud... is it necessary to have a working auto feed on a small 120000 btu steam unit with closed sytem?

nicholas bonham-carter

auto feed necessary?

i have a much larger system, with no auto/over feed, and it works fine. i do however live on site, and can check the water-level at least weekly. having a manual feed forces someone to look at the boiler on a regular basis which is a good thing. in addition, the first months of a boiler's life are characterized by a more active waterline which can play badly with an auto-feed, no matter what the delay is set for.

i hope when you replaced the boiler, that you sized the new boiler to the radiation, and not simply to the old one. this would also be an opportunity to keep the pressure low with a vaporstat [verified by a good low-pressure gauge]. lastly good main venting will make the system work as well as when first installed.--nbc

reds

vents

agreed thank you, I am dyl landlord not by choice. also yes I sized the unit since the building got divided. once unit was up some of the radiators were cold at differant times the following day. The room temp was maintained over night although some where cool and vents are hissing on the cool units. Boiler appeared to be running of and on frequently?sound about typical i am unsure..i assume the air needs to be fully bled?is it possible could be sucking somewhere? Thanks again

nicholas bonham-carter

hissing vents

if the radiator vents are hissing loudly, then you need more main [not rad] venting, or your pressure is too high. my venting of the mains on a 55 rad system, takes place with a back-pressure of 2 ounces, and i have 16 gorton #2's on 6 dry returns. extra pressure, and inadequate venting is a waste of fuel/money. comfort and evenness will be greatly improved.--nbc

reds

7 rads

I have 8 on second floor and hoffman #1a on the rads,seems to be two on the main one going left upstairs and one right then on first floor there is one more before going to rads on second floor. My pressure gauge reads less then 2 on boiler.

nicholas bonham-carter

not by choice

how many main vents on the returns are there? they do all the work. when you hear the radiators hissing, it's the sound of the gas meter selling you extra gas to squeeze the air out of the radiator vents instead of the main vents.

if that is a 0-30 psi, they are not very accurate at the ounces range these systems need to run their best.

how did you size the boiler capacity?--nbc

reds

size

i sized the unit by measuring the units plus the amount of fins and width of fins. Then ordered the next size up because it was the same size as the 75000 but the 120000 was more effective?

nicholas bonham-carter

boiler sizing

not quite sure i follow your method. when you size a steam boiler, you definitely want to size it to the total radiation capacity, not the heat-loss [which you would use for a hot water boiler]. if you have too much boiler capacity, there will be short-cycling as more steam is produced than can be condensed by the radiators, and if the size is much smaller, you won't be able to get all the radiators hot at the same time.

if you are right on target, the boiler will produce just enough steam to be condensed at a very desirable low pressure--nbc

reds

radiation

i followed the process to get the size that was necessary. I may be pre mature in thinkinig the vents or short cycling are a problem since only one day has passed. i will see by monday if there is a concern for real and post back.

nicholas bonham-carter

Expired boiler replacement

That's a good plan. I was just wondering about your apparent upsizing from 75,000 to120,000, and whether that would explain the hissing vents.--NBC