steam from condensate receiver

John Conway

I’ve got 2 pipe steam, circa 1920’s(?), last updated (to LPG) in the late 60’s or so. I’ve had no success finding a professional to repair & maintain the system here in western South Carolina. The Wall and Dan’s books have been very helpful, but I still have a number of problems to resolve. I’ll try to be to the point:

1. Steam is leaving via the condensate return vent. I understand that implies failed thermostatic traps. I replaced the capsules at every radiator & system performance dramatically improved, but I still am losing steam via the vent. I can close all valves at the radiators & still get steam at the vent. Granted the valves may need repacking and the steam loss is much reduced compared to before the repairs, but I shouldn’t get any loss, to my thinking.

2. Can any competent, LP-qualified tech check and adjust the burners (& flue)?

3. Likewise, can any pro check and adjust thermostats or does he need to be boiler-aware?

4. The burners are short-cycling. A complete cycle takes only about five minutes & the burners are firing about 33% of the time (flame for 20 minutes and none for 40 minutes in an hour), I presume this is because I’m losing pressure (point 1 above).

5. Also due to point 1, I’m making up water far too frequently. Eventually I’ll chew up the boiler. There is a terrible harmonic vibration set up by the water feeder (M+M 47-2) that is passed along the pipes to the most distance reaches of the house. That can’t be good for the equipment.

I’ve got more system issues, but solving the first one would be an immense step forward. I plan to replace the pressuretol with a vaporstat, but I’d like to solve the steam loss issue first. Besides replacing all the thermostatic capsules, I’ve replaced the head assemblies of both Hoffman F&T’s and replaced the valve, cartridge & strainer of the M+M 47-2 (which had failed). I’ve cleaned out the pigtail, etc. and cranked the pressuretrol way down. A hack replaced what I suspect is a perfectly good (‘though obsolete) Honeywell Modutrol and replaced it with a later model that doesn’t quite close the valve. The pipes (& innards of the various controls) have been pretty clean – not all scaled up – which seems reasonable considering our water quality. With the likely exception of the Modutrol, I don’t mind the parts expense – the system needed the maintenance. I am tired of paying hacks – the last three made problems worse and missed the real issues.

Sorry for the length of the post. Thanks for all the valuable (& entertaining) stuff on the Wall.

Steamhead

That could be \"flash steam\"

where condensate leaving a system under pressure flashes back to steam when it reaches atmospheric pressure. What pressure are you running in that system? Sometimes Pressuretrols aren't that accurate- maybe the Vaporstat would be a better choice. Get the one that only goes up to 1 PSI.

Any LP gas man should be able to tune those burners. Also the cycling problem is easily fixed if the thermostat is causing it.

Try installing a pressure-reducing valve, as used on a hot-water boiler, before the 47-2. Set it to 12 pounds, or as low as it will go. This should cure the harmonics.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

John Conway

Thanks for the rapid response.

The pressuretrol is set to cut in at about 1/3 or 1/2 lb & out at 1 1/4 or 1 1/2 lb. I could reduce the cutout some, but The cutin is pretty much at bottom. (That's down from #5 in & #8 out where the last guy set it!) You're right - it can't be very accurate - nor can the pressure gauge; but the burn cycle is consistently between those settings acording to the gauge. I'm guessing the pressuretrol & gauge date to the 50's or so - the pressuretrol is a Honeywell P104A1---4 & the gauge is a 3 1/2" Jas. P. Marsh compound (30VAC-30PRES). I'll order a vaporstat Monday and resume my search for a knowledgeable technician locally. What about gauge replacement as well? And I take it anyone (any competent pro) could check & adjust the thermostats?

Steamhead

Yes, your LP tech

should be able to check and adjust the cycle length if needed.

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

John Conway

Getting out of the way of the tech

Upon sober reflection (it's hard to find a Guinness on Sundays around here), I've decided to hold off my purchase of a Vaporstat until I exhaust two more (two last?) leads in the search for a competent technician. Having spent some years in a technically demanding profession, I believe amateurs ought to stay out from under foot.

That said, I'm also tired of wasting money on bad work. My plan is to ask that the following work be done:

1. Install a Vaporstat. (In a couple of other threads I've seen advice to keep the pressuretrol - that sound right?)
2. Replace the relief valve (it must be 30 years old).
3. Test & adjust the burners.
4. Test & adjust the thermostats.
5. Add a pressure reducer before the 47-2.

Any advice from anyone on questions to ask, things to watch for?

Thank & peace

Christian Egli

How much steam is coming out of the vent? Really lots?

Wisps of steam coming from the return vent could be considered normal, but not steadily streaming steam.

Could there be a third F&T trap hiding somewhere? or some kind of cross-over pipe from the main to the return?

Could the exiting steam come directly from the boiler, by flowing backwards through the equalizer into a pipe that may have been a wet return at some time in the past but is now a dry return with no water seal to stop the steam.

This could have happened when the boiler might have been replaced. Maybe there was some vacuum apparatus that was inconsiderately removed. (You did mention the Marsh 30 inHg vacuum gauge).

Make a mental note of where the boiler water level is and follow the pipes above that level to see where the steam can go leaving from the boiler. Not even last week, someone posted a question on the same problem.

Your short cycling might suggest that your boiler is over fired. Reducing the fire size is an option but there may be no benefit to doing that. Measure your flue gas temperature, if it is extraordinarily high (like above 600 F), then for sure, you will benefit by reducing the fire size.

Solving the steam leak first could be the cure for the short cycling.

Changing the pressure regulator might not help as much as you hope. It seems you are already running at acceptable pressures. Check to see if anything is giving wrong values first.

Since you have water hammer problems in your potable water pipes throughout your house, a water hammer arrestor, on top of the pressure reducer will dampen the noise and possibly save your pipes in the long run.

John Conway

Thanks!

I've found a guy who might know something about steam - I got some good, some discouraging noises from him. Walked him around the basement & the house, he asked me to do a bit of homework. Fair request. Meantime, he'll give me some written feedback. Fair again.

Been working on a Habitat house, trying to finish it up & get Mom & kids in by Christmas. My boiler takes the back seat.

Thanks again for your guidance Steamhead & Chris - I'll post again & appreciate any thoughts.

Peace.