Balance Problems

Jeff_74

I have a one pipe steam system and many of you have helped me tweak and
improve its performance. I am still having trouble getting it to come into
better balance. There are two steam mains... one is 46 feet long, the other is 53 feet. Both are 2" pipe and are well insulated.

The shorter side feeds four rads (@ 94 EDR) and is vented with two Hoff. 75s. It takes about 5 minutes for steam to get from the boiler to the end of the main.

The longer main feeds six rads (@ 187 EDR) and is vented with two Gorton #2s. It takes about 7 minutes for steam to get from the boiler to the end of the main.

Why, with the large capicity of the Gortons, does it take longer for this side of the mian to get steam. Do I need to vent this main with more capacity? This side of the house is always slower to heat. Is the imbalance in the EDR load causing the imbalance in the stystem? The only way I can acheive any eveness is to shut off one or two rads on the longer (Gorton) side.

I should also say I just had our 65 year old boiler replaced with a new Dunkirk steamer. The balance problem was present with both boilers.

gerry gill

how long does it take to

get steam to the long side vent tapping if you remove the vents and have an open pipe..you add as many vents as you can trying to achieve this same time..you have what i call ''runout robbery'' where even tho the main is vented well, some steam is being stolen from the main by the runouts as the steam passes them..remember they are vented too..you can also try the timing with only one hoffman 75 on the short main and a plug in the second opening.

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Boilerpro_3

Radiator venting

Have you balanced your radiator vents? Adjustable vents from various maufacturers allow you to balance the venting of the radiators. It sounds like the rads on the one main are nearly twice as big as the other, so they would need twice as big of venting. With the adjustable vents, I usually only use the 1 to 3 range, as going bigger than that will effect the venting of the mains considerably. If the the rad vent is too big it will draw the steam into that radiator and not allow enough to fill the main completely. The old Hofmmann No 40 only had a 1/8 inch vent hole flowing at only .1 cfm. The general recommendation for venting has TWO parts, vent mains quickly AND vent raditors slowy, but clompletely. The key to good operation is doing both. Big vents on the mains, small vents of the rads.

Boilerpro

jeff_57

That's what I've tried to do...

I have adjustable vents throughout and it seems to work best if I squelch back the big rads and open up the small ones (just opposite of what Dan's books say).
On the side with more EDR, the first three rads on the line are all BIG and seem to suck up a lot of steam. The real problem is that the last radiator on the Big side has the most effect on the t-stat. If I close one of the big rads, the rad near the t-stat heats evenely. If I don't, then it takes longer for the T-stat to be satisfied and then the upstairs gets way too hot! Do I need bigger vents on the
big rads or should I keep trying to squelch them back?

thfurnitureguy_2

Just a thought. The goal is to heat the house with even comfort. Is this goal being reached? It is not a perfect science. If the house was not designed with perfect conditons. You could go back and do a room by room heat loss calc, add the proper sized radiators to match the heat loss for each room and replace the boiler to the new matched load, But...... I would adjust the rads to where they are as even as possible, with your stat room heating as fast as possible. Thus giving you the shortest run time with max comfort.

What happens if you open the stat room rad all the way up? Can you adjust the rest to comfort, with the stat room rad full on?

Boilerpro_3

Venting capacity and Radiator size

When the radiators were first installed and they matched the heat loss properly, bigger rads needed bigger vents. However, the loads may have dropped more in the rooms with big radiators when new windows, insulation, etc. has been completed over the years, so they may need to be squelched. It sounds like the big rads need to be squelched, so the thermostat radiator heats properly. Then balance the rest of the system against this thermostat radiator.

Boilerpro

Jeff_74

Thanks...

For your suggestions. The other problem is that the riser/branch that serves
the radiator nearest the t-stat does not have enough pitch. (see pic) It appears that the branch is near level, but when I put a level on it, it actually pitches backwards. I assume this would also have an effect on this rad's performance and thus the whole system.

Am I barking up the wrong tree?

jeff_72

Will this cause the steam to cool?

With this backward pitch, will it cause the steam to cool, return to condensate and therefore, impead the performance of the attached 1st floor rad?

gerry gill

pitch of steam pipes

is critical..

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