Is my two pipe steam system working as expected ?

Jchenabc · February 5

Hi, first of all, like to thank everyone on this form. Learned so much in the past month. First time home owner of a 100 year old 2 pipe steam system. This is our first winter at the house, and the boiler decide to leak and die.

Under the circumstances, we just went with a straight replacement. Lowered from 250k to 238K BTU base on EDR calculation. I learned about how steam trap needs to be replaced every few years. So far, I have changed about 10 out of 20ish traps. They all had traps that was original to the house, dating back in 1927! I noticed some new behavior after changing traps.

Seldomly, any radiators will get fully hot all the way across. We have pretty big tubular radiators (5 tubs, 20" 20 sections) the top will get hot and the heat never fully work its way to the lower section. As I understand, condensate will form as it warm up the thing?
Some of these radiator would get fully work prior to the steam trap rebuild. My theory is the trap was previously broken on the open position, leaving steam to escape all the time. With the new trap, it is somehow closing before steam fully hit it ? I am using the barnes and jones 1764 traps btw.
The other thing I notice is that the pressure gauges on the boiler is always at 0. I assume it has to do with the old trap just letting the steam escape? The water level gauge does move a little when the boiler is going, but nothing too crazy.
I have a nest controlling the temperature, boiler usually fires for about 30 minutes on each cycle. I don't think it ever shuts off because it reaches PSI.
There are two air vents near the boiler, one on the supply (up front) and the other on the condensate return line.

I have temperature sensors in rooms that I have rebuild the traps, they are even out pretty nicely. No clear hot or cold spot like it use to. (maybe 3-5F delta before , now within 1F of each other). So in that aspect, I think something is working? I have some Tunstall traps in order for the rest of the radiators. Just to check in and see if that's normal behavior, and I am not actually doing more damage to the system. Thank you.

delcrossv · February 5

Looks like things are improving.

Some things to note:

Quality trap elements should last many years.

Radiators hardly ever heat all the way across. Are the rooms comfortable?

I do not understand having a vent on your boiler header. A mains vent should be at the opposite end of the main if you do not have a crossover trap there. What's at the far end of your mains?

A 0-3 psi gauge will be helpful to know what your system is doing.

Jamie Hall · February 5

It actually sounds from your description that things are working pretty well.

If some (or all) of the radiators don't get fully hot — not to worry, provided the heat in those rooms is adequate. They will only get really fully hot until you have, for some reason, a really long boiler run — indeed, until the boiler builds enough pressure to shut off on pressure, rather than when the thermostat is satisfied (which is exactly what you want it to do).

The apparent low pressure at the boiler is normal. Many two pipe steam systems run quite happilyat less than a pound, and a surprising number on only a few ounces. Unless you have a low pressure gauge, you'll not see that pressure at all.

Jamie Hall · February 5

Oh — one more thing. The pipe to which you refer as "condensate return" is properly called a dry return — and the vent on that pipe is critical, as it is the way that air gets out of the radiators.

Jchenabc · February 5

https://forum.heatinghelp.com/discussion/comment/1840321#Comment_1840321

You are right, the condensate return is actually much lower on the side of the wall. Hope I see some improvement on the gas bill with all the trap rebuilds. Thank you for confirming.

Jchenabc · February 5

https://forum.heatinghelp.com/discussion/comment/1840317#Comment_1840317

Last month's gas bill was crazy. We since lower the temp to 68 from 70 for the most part. It is doing a better job maintaining a steady temp. Especially the nursery for our 4 months old. So I am very happy about that. It used to be always 3 degree cooler than the thermostat, now it matches. Not quite sure about the vent. There is one on the back on the dry return. The two thicker main just splits off to all the radiators.

delcrossv · February 5

https://forum.heatinghelp.com/discussion/comment/1840327#Comment_1840327

I see that one in the back. What does the far end of the main look like? should be a drip line or a crossover trap at the far end

Steamhead · February 5

If @Jchenabc is using B&J 1764 kits, this is a Webster system. Maybe that steam pipe off the header with the vent on it, once fed a Return Trap?

delcrossv · February 5

https://forum.heatinghelp.com/discussion/comment/1840352#Comment_1840352

I think we have a winner. 👍️

Jchenabc · February 7

Indeed I have a Webster system. So this is kinda interesting. The tunstall TFWW-2515 trap arrived. I swab out of the radiator that wasn't getting as hot as before to the Tunstall, and noticed a big different. B&J's trap has a really small opening when the bellow is in open position. I think what is happening is as the radiator is heating up, condensate forms. The small trickle of condensate was enough to form a air seal on the outlet, and prevent the steam from pushing further though the radiator, I am think my system is running on pretty low pressure.

One other question i have regarding to trap rebuild. If I somehow miss a trap, does it make the whole exercise kinda pointless when it comes to energy/steam saving? Since the steam will just continue to escape from that one missing trap ? There are a few more trap in the unfinished basement. One connecting the steam supply line to condensate return. They are kinda hard to get to, do I need to change those as well ?

delcrossv · February 7

One connecting the steam supply line to condensate return. They are kinda hard to get to, do I need to change those as well ?

That's your crossover trap that vents air out of your main. that needs to work.

EzzyT · February 7

@Jchenabc I recall informing you about replacing the trap cages when I was at your house to give you the estimate on the boiler replacement. Has the main venting been upgraded as I suggested? Plus in my opinion that boiler should have had both tapping used.

Jchenabc · February 8

I have about 3 more traps to go. Have some fiberglass insolation coming for the exposed pipes next week. Did not get a chance to upgrade the vent yet, i think that is next in the list, or fixing some of the inlet values. The good folks at Tunstall has a repair kit for the valve for $125 a piece. It is not cheap to keep up with a old system. Is the idea of new Gorton #2 to be able to vent faster compare to the two existing vent ?

Sorry, redoing the pipe work was out of our budget at the time :(

Really appreciate your time.

Is my two pipe steam system working as expected ?

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