steam timing

Victor_3

Steamhead-

I may have some sort of hybrid system - My two mains with their corresponding dry returns are 25' at 2.5" pipe and 17' at 2.5" pipe with similar length dry returns coming back with 1.25" pipe. Then off of those two mains I have several long horizontal (but pitched) feeds to various other radiator risers in crawl spaces, etc. Those long runs (I have several) vary between 16' up to 25' and are all in 1.5" pipe with no dry or wet returns coming back off of them. My main vents are back at the end of my dry returns, but there are no vents at the end of those other long single pipe horizontal feeds. Could that be a problem?

I know they put "faster" vents on those radiators that are at the end of those long horizontal runs. All the radiators do seem to get hot at the same time.

Thanks for your input...

Victor

Steam Timing


I understand a lot depends on the various specifics of a system, but just roughly, what is the average time it should take from when the thermostat calls for heat until the steam radiators start to get hot?

In my steam system it takes about 20 min. They tell me all of the main vents and radiator vents have been replaced (with gortins ??) and all of the pipes are insulated, etc.

The boiler starts from rest and 20 min. later all the radiators are just getting hot. My contractor tells me that is normal - what do you guys think? Should it be quicker?

Unknown

I'd break it up

Turn the thermostat up on a cold system. Go to the boiler and time it untill it makes the piping above the boiler steam-hot.

Then start timing from then untill the main vents at the ends of the mains get hot. That should be 1-2 minutes. Longer indicates room for improvement.

After that, all of the risers and radiation should BEGIN to heat together.

It should run till the thermostat satisfies, after that. That is usually determined by the windows and doors; and the insulation and infiltration.

Noel

Victor_2

Noel -

I have a one-pipe system with two mains going opposite directions in the basement. Both have dry returns that drop back down within a few feet of the boiler. That is where the main vents are located. The short main/dry return has two Gorton #2's and the long main/dry return has 3 Gorton #2's.

Here is my time record:

0 - Turn thermostat up

1 min - boiler making steam (i.e. pipes out of boiler hot)

12 min. - end of short main/dry return/vents hot

13 min. - end of long main/dry return/vents hot

16 min. - all 1st floor rads begin to get hot (all at about the same time)

18 min. - all 2nd floor rads begin to get hot (all at about the same time)


The boiler is five sections. I have 17 radiators. The house is approx. 3000 sq ft.

Does this seem normal or too slow?

It otherwise heats fine and there are no problems - I am just curious if this timing seems acceptable.

Thanks

Steamhead (in transit)

How long are your mains

and what pipe size are they?

Steamhead (in transit)

It may help

to move the main vents to the ends of the steam mains. Sometimes excessive heat in the boiler room can cause them to close prematurely. This also avoids filling the dry returns with steam unnecessarily.

Have a pro do the moving if you're not comfortable with it.

Victor_4

Moving Vents

Okay Steamhead Thanks.

I am not sure I feel comfortable drilling and tapping new holes at the end of the mains so if that is the correct route I will definitely hire a pro.

Would another alternative be to extend my current vents on the end of the dry returns with various nipples or lengths of pipe to get them up and farther away from the boiler? Would that help keep them cooler?

Just a thought - I would be able to make that move myself since it would be just a matter of buying some more threaded pipe, etc.

What do you think of that? Could it help? If you think this might be helpful (although not necessarily what a pro would do) how far away do I need to be to prevent the premature closing?

Steamhead (in transit)

Well, if you move them up

it might make things worse, since hot air will stack up against the boiler room ceiling. Now, if the vents are close to a wall and you can go thru the wall with a short piece of pipe, that would be worth trying. Be sure to pitch (slope) the pipes back toward the dry return so condensate can drain.

If the system is still slow to fill with steam, look at the chimney top while the boiler is running on a chilly day. If you see a white plume coming out, that's steam. It means the boiler has a leak above the waterline and must be replaced. You can confirm this by shutting the boiler down, letting it cool, and filling it up past the top of the sight glass so the water rises into the steam outlets. If you get water in the firebox or on the floor, you know you have a leak. Drain the boiler back to its normal level before restarting.

Victor_5

Leak

I'll try moving the vents off to the side away from the heat of the boiler stack etc. (but still sloped back) as I do have room to do that.

In refernce to the leak - I hope that is not the case, but one indication that makes me think it is not is that I rarely ever have to add make-up water. My system is very tight in the sense that I only have to add water (and even then only a small amount) a couple of times during the entire winter. Would you concur that might rule out the leak possibility without having to go through the flood test?

I appreciate your advice and help.

Steamhead (in transit)

Sure is

but if the vents are OK and it's still slow to heat, there has to be a reason. Maybe the firing rate is too low?

Victor_6

Okay. Thank you for all of your help.