Steam boiler condensate return question?

tim smith

Hey all, have a low pressure steam boiler I am working on, 2 million btu. The Contractor who installed it had 1 low entry condensate line from east section of building that came in below slab of basement units, picking up also some of that side upper units also. The line comes in boiler room lower than the water feed tanks water line for boiler. All other condensate lines go to feed tank as they are overhead. This scotch firebox boiler has 1 6" supply and the pumped feed just goes in back of boiler no equalizer or hartford. Right now the installer just was letting condensate go to drain sump. Rrrrrrr. So due to level of feed tank and height of radiators in basement units, I can't go direct with pipe to feed tank. Our options are a small condensate receiver pump to pump to feed tank or, here is my question. Could we install an equalizer line and bring low gravity line into it via a hartford and leave rest of condensate lines in feed tank controlled by the MM 150 or just better to do the receiver pump and pump to feed tank? Kind of a cluster but just trying to figure best practice. Ideally we could bring them all back to a hartford on new equalizer but that would be quite a bit of extra work! Worth it?? Not sure, maybe in long run?

Thanks in advance for any input

Tim

Jamie Hall

Is there any good reason not to flood that return line? Like nothing feeding it which is below the water line (or actually a bit above) the water line of the water feed tanks? And would I be correct to assume that the water feed tanks are vented? If that's the case, I would avoid the complexity of any more pumps and tanks, and bring that line up above the water line in the feed tanks, then a short connection (sort of like a Hartford Loop) with a vacuum breaker on it, then on into the water feed tank. The line would flood to the level of the sort of Hartford Loop, but would drain through that, and the loop and vacuum breaker would eliminate the possibility of a leak in the line draining the water feed tanks.

At least if I'm understanding your description correctly…..

tim smith

Jamie Hall, I think the water line in feed tank would push condensate back up into basement radiators appx 12”. Also would limit air being pushed out. 2 pipe with traps.

retiredguy

I would go with what @Jamie Hall suggested unless as you said that the condensate would back up into the lower part of any radiation. If that is the case, then I would cut the concrete floor and install a very small condensate dump tank below the condensate lines under the floor and pipe the pump's discharge into the feed tank.

tim smith

retired guy, the receiver tank/pump is my initial thought due to feed tank water line above bottom of basement radiators by appx 12”. Posted to see if maybe better alternative.

Jamie Hall

https://forum.heatinghelp.com/discussion/comment/1811854#Comment_1811854

Ah. Missed that. If that is so, my solution won't work at all. In fact, even that weren't the case, if these are two pipe radiators venting though the trap it wouldn't work. Those have to vent into a dry return, not a wet one, which has to be vented.

Oh well.

tim smith

appreciate the input Jamie. It kinda perplexes on the best way to handle. Air venting was a concern.

Tim

EBEBRATT-Ed

Most scotch boiler don't require a hartford especially with a pumped return. The best fix wiyld be a condensate tank sunk into the boiler room floor. I am not talking about making a pit for a pump but they make vertical condensate tanks that are installed by digging the floor and the top of the tank sits flush with the floor.

Check out Shipco they can make you a tank with the dimensions you need.. Raising the condensate will block air venting from the low returns without a pump.

Unless you can find a small candensate pump to pump to the boiler or feed tank.

tim smith

Ebebratt, what they should have done was install a horizontal feed tank then all could have gone into it, its a vertical Shipco, appx 80 gals. only 4 yrs old so kinda hate to have customer spend all the money on reconfigure and another largish tank. Thats why maybe a small receiver tank/pump on floor which will allow this low line to go to then pump to feed tank. Hate having to add another piece of equipment but can't fix bone head moves easily.

jumper

May waste some steam but I'd investigate using a venturi injector. Can probably be subcritical unless your low pressure is truly low.

Pumpguy

Shipco now offers their submerged condensate units with stainless steel tanks.

Unfortunately, lead times have been quite long lately.