No heat in last 2 steam radiators

Fred Harwood_2

Those crossover vents were important, and the 75 is too small. Assuming that you are not using vacuum, install Gorton #2's for mains venting, or restore the crossovers.

Do not raise pressure. Especially important, ensure that the dry return vents freely back at the boiler. Those rads are still connected to the dry return, and it must vent well, not just the mains.

Terry_23

No heat in last 2 steam radiators

We have a 2 pipe vapor/vacuum system that had boiler recently replaced. System works OK, but no heat in last 2 radiators on each steam main run. The risers to the valves are hot. We also replaced all thermostatic trap elements and new F&T at the end of each main. We replaced the vent on top of the Hoffman differential loop with #75 vent. He cut out crossover traps at end of main and installed #75 vent in place of it on supply side???? Should it be on dry return side or both? Should I put one on each of the F&T extra legs? to aid in air removal and maybe heat the last 2 rads.? Do you need pitch to and from the F&T inlet and discharge? Sorry so long too many questions!!

Thanks, Terry

Terry_23

Our contractor wants me to jack up the pressure to fix the non heating rads.

Supply House Rick

jacking up the pressure

keep the pressure low-between 5 and 12 OUNCES. your pressure may be why the traps are not working. get a good gauge [0-2 psi, gaugestore.com] and see where your pressure is. you might as well get a 16 oz. vaporstat now, as you will need one later with this type of system. you could start now with a more economical,comfortable system instead of waiting until next winter. you may also benefit from larger main vents than those hoffman 75's [gorton #2 may be required pex supply.com]. tell your contractor that jacking up the pressure is like fixing stuck brakes by pressing harder on the throttle!

both of you could learn much from a copy of "the lost art of steam heating" available here.--nbc

Terry_23

Thanks for the reply, the system is running from 6oz. to 16oz. I bought 16 oz. vaporstats and they seem to work great. I also bought the "steamy deal" including the "Lost Art Of Steam Heat" and have read it twice. Still looking for suggestions on vent locations or putting the crossovers back in?

Unknown

when you say you have..

When you say you have steam/vaccum system... real tricky here, hoffman loop must be at right level. Put the crossover back in places, deadmen didn't put them there for no reasons. Had one job with crossover missing. Thanks again to Dan's books, I put it back and system works so much better, especially with the vaccum pump system.

Terry_23

Thanks Fred, It sounds like I should put the crossovers back in, but there is still 1 crossover on another main branch that remains and there is no heat on the last 2 radiators on that side either??? Maybe I should open the trap on those rads. and see if steam comes around the radiator?

Fred Harwood_2

Open trap

Yes.

Jamie Hall

You absolutely need

the crossovers traps. They can be perfectly ordinary Hoffmans -- a typical all-Hoffman system would have probably used 8Cs, which are easy to get. Depending on the pitch of the mains, they may not only 'vent' the system, they may be allowing condensate to escape the steam mains. Fix 'em. As someone said, the dead men didn't put stuff in they didn't need.

Nicholas is absolutely right on pressure -- whatever you do, don't let your plumber jack it up. That would be exactly wrong. Since you have vapourstats and I think you mentioned a differential loop, crank the 'stat down to 12 oz. -- no more. Otherwise the loop won't work right.

There MUST be a main vent where the dry return comes back to the Hoffman differential loop. No ifs, ands, or buts. I'd suggest at least one Gorton #2, or maybe two -- but pipe them so steam or condensate can't go straight up from the loop and hit them.

I may think of more later...

Terry_23

Crossovers

They did use Hoffman traps, #8 maybe a predacessor to the 8C? I kept those after he took them out, so I can pipe them back in. Should I make sure there is pitch out of the F&T traps at the end of the mains being such low pressure at that point,it might not push the condensate back without some pitch down instead of up an inch or so? Also what do you think of the #75 vent on the extra leg of the F&T?

Jamie Hall

Dry retunrs

either have to pitch back to the boiler and then down to the wet return or have to have drips to the wet return at the ends... otherwise you'll get condensate building up in there, and the air won't be able to get back to the main vent.

Terry_23

Thanks Jamie, and others that replied. I will try these ideas and let you know how things work out. I appreciate your expertise and so will my church !!