Problem Dry Return Line

zachs

I have searched throughout the site but could not find any threads that mention this. I have a medium size apartment building with steam heating one pipe system, dry returns.  The problem is prior to acquiring the property the previous owners had made some major repair mistake on a steam system and rerouted the dry return to slope up a significant amount. This obviously has caused that entire line to not drain back to the boiler. The other main lines are properly sloped and working great, so the boiler is in no danger.  The solution I came up with is to install a condensate return pump on that one section to pump the water back to boiler. I have had difficulty locating sizing of pumps for this system.  Any help would be greatly appreciated. 

The boiler is steam one pipe system dry returns approximately 1,125,000 btu input, pressure set at 2psi

Jamie Hall

Oh dear...

is there any hope at all of running a vertical drip line from the lowest point of your mis-routed dry return down to floor level, or very nearly so, and then back to the boiler?  So long as it stays below the boiler water line, it can go up and down and sideways pretty much as it wants to.  That will take care of that condensate by gravity... which is much more reliable and easier (not to mention cheaper) to maintain than a pump!

nicholas bonham-carter

give gravity a chance

as jaimie says, gravity is the way to go, although you would be well advised to install a vaporstat and cut the pressure down to 8 ounces max, which will aid in condensate return.

i have 55 rads, and 1,050,000 btu and all gravity, and also no auto-fill to wory about, so i can run my system off a battery back-up for quite a few hours..--nbc

Dave in QCA

Battery Backup?

I am very interested in the battery backup that you mention!  Please start a new thread with this as the Post Title.

I have been wondering about the possibilities of the same thing.  I have a condensate tank and pump that is not needed on my vapor system now that I am limiting pressure to 8 oz with a vapor stat.  Gas valve is 24 volt, controlled by a Tekmar 279.

zachs

Problem dry return

Unfortunately,  running a vertical drip line and then back to boiler is not an option due to ground level and many solid stone walls.  Not sure I understand how lowering the pressure down to 8 oz will help with the condensate return.  Originally the vaporstat was set around 5 psi, i believe previous owner was trying to push the condensate through the return line, all it did was increase the bills and clogged the radiator vents constantly.  After reading a few threads last year I determined an optimal pressure was between 1-2 psi, any thoughts.

Jamie Hall

As to pressure and condensate return...

Best thing to do is to read Lost Art thoroughly -- but in a nutshell, there is pressure in the boiler.  This pressure extends pretty well through the system to the radiators, but does not get into the returns.  Therefore, water is pushed backwards out of the boiler into whatever riser(s) connect the boiler to the dry returns -- the height is proportional (roughly 2.3 feet per pound) to the pressure.  So the higher the pressure, the higher the water will stand in the returns.  Too high a pressure can even flood the dry returns, with interesting results.



Your optimal pressure probably is around 1.5 psi, more or less...

clammy

condensate pumps ?

I just read your post and as others have suggested do yourself a huge favor and many less headaches and money and add a tee with a vent  and about a 2 ft piece of pipe and then  drop the dry return down below the water line and run it back to the boiler as a wet return ,find yourself a good steam mech who is well equipped with a core drill and let him do the work ,drilling through interior masonry foundation is not that big of a deal .Have him add  some cross tees along the way for future flushing of that wet return .in the long run you will be much happier with a no maintenance ,no moving parts gravity return that will never need a service call because it is not working or the pump burnt out cause the float was stuck ,I have in the past worked on small apartment buildings like yours and gravity is the way to go, install a vaporstat,re do your main vents possible add more vents ,insulate all your mains 1 inch wall fiberglass mimiun and if you can get a 2 stage gas valve (check with the boiler manufacture )working off the vaporstat  the only thing i would add is a temperature averaging thermostat using 3 indoor sensor in the worst apartments (coldest ones )and then you are done ,i have done  exactly what i have said in a few smaller apt.building (16 to 32 units )and cut there gas bills more then in half also in 2 of them removed and discarded the condensate pumps.Find yourself a real good steam guy if they don,t seem to understand show them the door there are alot of wolves in sheep clothes and none of what i have state is brain surgery it's just basic steam, tune it up ,clean it up and your done peace and good luck clammy