Pulling Trap Guts

BAB

Over the last 5-10 years have altered system (thanks to your guidance) to be lower & lower pressure.  Now operate always well below 1psi.  Have a true low vapor system, not pressure.  Have five mains in the commercial building each with their own respective motorized valve  The main with the longest run (250 feet from boiler) gives me the most problems.  Did entrapped air tests & started installing Gorton #1's.  Got good results so spent the big bucks & got many #2's.  Have about 12-15 Gortons on that zone main header only.  Made much progress but that zone still hogs about 25-33% of the boiler cycle time.  In that zone I have 10+ radiators each about 14 feet long, ... 3-4 of these are critical for heat control.  Even with the fantastic air venting they take forever to fill with steam/heat.  I even put small Gortons (D's) on the radiator ends & also on the pipe feeds/runs to the radiators.  In this last cold spell I pulled the guts from the steam trap on one of the 14' radiators & was going to replace.  I got distracted for a day or so & did not get to replace the guts for over 48 hours, ... that radiator & trap had now cycled many times.  The radiator, with the trap guts pulled was now fully heated to the end & performing great.  The radiator never cycles long enough to become completely hot (top & bottom) and the condensate draining to the trap is always cool.  When my radiators are hot they are hot on the top portion only, ... rarely on the bottom also.  Because my system runs with so low pressure & because I am so far from the boiler on this zone & because I have so much trouble bleeding air from these radiators, .... can I pull most of the trap guts on this problem zone?           . 

EBEBRATT-Ed

Pressure

It's all about figuring out the pressure drop of your piping system. I would suggest fixing the traps and raising the pressure 1/2 a pound at a time provided all the traps are working and the piping is correct.

JStar

Steam

You probably need about 20 ounces (1.25 psi) to operate your system correctly, if it's really 250 feet from the boiler to the furthest radiator.



You can remove the trap elements and install orifice plates in the hand valves. Don't remove the elements without providing some means for keeping steam out of the returns.



You also should not need vents on the radiators, and it would be best to remove them and deal with the problem properly.

BAB

a little more advice

I do not understand the recommendation to increase the pressure of the steam supply.  For the years on this website & books the message was always to reduce the steam pressure. Yes, the main steam header is a good 250 feet long.  A look at the pic of the building will show eight window sets on the first floor.  The rooms or bays with the windows are each 20 feet long.  The main steam header vertical lift from the boiler in basement is 15 feet and the additional cross building runs are.another 75 feet.  I can get the steam to the end of the building no problem thanks to the air venting.  I also understand the concern for the potential of steam bleeding into the condensate returns.  However, knowing my low low vapor pressure system on this very long pipe run I can not see how bleeding can happen especially through the 14' long radiators.

Thanks for your comments thus far & please further explain your concerns & your suggested approach.         

steamedchicago

friction in pipes..

Steam pressure should be as low as possible, but still high enough to get the steam where it needs to be quickly.  Most of the systems people have on here are for houses and other small residential systems.



As you increase the length of the pipe, you have an increasing drop in pressure at the far end.  You might have 8 ounces of pressure at the boiler, but you'll have less at the end of the pipe.  And it appears that you don't have enough, if you can't heat the radiators.

EBEBRATT-Ed

re engineer

You got two choices. Keep experimenting or figure out what the system needs.

As I posted earlier IF all the piping and traps are correct and the steam pressure isn't getting the job done in spite of all your venting then raise the pressure and try it. What do you have to loose? You can always lower it.

If you don't want to do that then collect the ratings for all the radiation, check all the trap sizes with a 2:1 safety factor, check all the main and branch sizes and condensate and return line sizes to determine the steam pressure you need.  J star is right the radiators should vent through the steam traps. You should only need vents on the ends of the mains.



Are you sure you don't have any master traps or clogged returns or loops piped into the condensate lines?  Are the condensate pump overflow and vent lines open and unrestricted?

nicholas bonham-carter

Motorized valves

How are those valves controlled. They must have been added later as a bandaid for system disrepair, so make sure they do not close, as you are making these tests. A good low-pressure gauge will tell you a great deal about the resistance of air escaping, and more.--NBC

BAB

bitter pill to swallow

I thought I saw a table indicting that 1/2 psi could travel fine up to like 500 feet without appreciable pressure drop.  You guys never give me the easy answers.  I wanted you to say that if pulling the guts of traps works , ... keep doing it.  It is easy to do & I just wanted your blessing in case something went wrong.  However, what you suggest does make sense, .... but ... my boiler is maxed out.  I can not just dial in a higher pressure.  I will have to hard wire up the other four zones to close their respective motorized valves so all my steam will be sent to the needy zone.  I will then set the vaporstat at 1.25 psi.  I can do all that but will not have results for a week or so.

My boiler has two 3" steam discharge stubs.  The needy 250' zone starts from the header as 3" pipe size.  When I close all the other four zone valves completely (they are 2" & 2.5" pipe size) I should be able to pick my pressure setting.

Thanks for the comments.  I can afford to run the steam boiler only because of the advice & help I have had on this website.

Someone asked about the motorized valves.. They (Honeywell) are activated/controlled by a room thermostat.  A micro switch is turned on or off by the valves (valves are Jamesbury) moving lever arm which then turns the boiler on or off.  

JStar

Pressure

To figure out what pressure you need:



We assume that the original system designer sized all of the piping at a pressure loss of 2oz per every 100 equivalent feet from the boiler to the furthest radiator. So...



250 ft = 5 ounces

Pressure loss of fittings (estimated at same as length of pipe) = 5 ounces

Safety margin = 2x Total Equivalent Length (pipe and fittings) = 20 ounces

20 ounces = 1.25 psi



Technically, you only need 10 ounces to reach the furthest radiator. HOWEVER, that is when the pipes are completely dry, with no condensate to slow down the steam. It also assumes that our measurements are accurate, which is impossible. If you install a low pressure gauge on the furthest radiator, you can compare the pressure at the radiator to the pressure at the boiler. Subtract the two, and find the operating pressure that you need.

seabee570

rad help

if possible,install trvs on as many radiators as you can.