Cast iron baseboard steam trap

DuaneK

Looking for advice on adding traps on my cast iron baseboards. They never had traps. I'm guessing that they should have them. They do have valves on the inlet end.
I have 5 original convectors (with traps) and 4 cast iron baseboards.
The baseboards measure:
24" X 10" X 2"
36" X 10" X 2"
42" X 10" X 2"
I have a 2 pipe system with a new Burnham Megasteam boiler. New Hoffman #75 main vent.
Thanks for your input!
Duane

Jamie Hall

Did you have difficulties with the previous setup? And if so, what sort of difficulties? Where do those baseboards drain to?

DuaneK

No issues before or after. They drain into the dry return. I changed them about 20 years ago. Mainly for aesthetics. The cast iron baseboards look and work great.
I'm just wondering if the steam is entering the return.

Jamie Hall

Easy enough to tell if steam is getting in there -- measure the temperature, either by the hand test (yeouch is steam, dang hot is hot condensate) or better with an IR thermometer...

DuaneK

They're very hot, yeouch hot!
I was getting some pipe hammer after the new boiler install. I installed a 6" nipple under my main vent yesterday. I think that took care of the pipe hammer. Still need to skim it.

The pipe hammer had me thinking that the baseboards could be contributing to the hammer.

Also, the very last convector isn't filling completely. Very hot on the inlet side, warm on the other end. Nothing returning (can hold the return pipe).

Would traps on my baseboards force more steam down the main?

Jamie Hall

Sounds like you may need traps. It's not that they will force more steam down the main, it's that they won't let steam pressure get into the returns, where it will then keep steam from getting to the radiation.

EBEBRATT-Ed

I doubt you need traps if you never had them. Post some pictures of the boiler, boiler piping baseboard and baseboard piping so we can figure it out

AMservices

You can try throttling the supply valve to slow down the incoming steam. Try to have the baseboard condense all the steam before it reaches the return pipe

DuaneK

Thanks for the help!
The convectors are made by John J. Nesbitt. The last convector coming off the main is the one in question.
The other pics of supply and return pipes go to the cast iron baseboards.

See pics

Danny Scully

Orifices maybe?

EBEBRATT-Ed

I wouldn't add traps that will probably screw it all up. So you only have 1 convector that isn't working.

Check if here is a valve with a broken stem or possibly a plugged orfice

Jamie Hall

I was hoping orifices... and throttling might work. I'm concerned about the OP's comment that the returns are very very hot.

nicholas bonham-carter

Unless the system is very small in terms of pipe length, one Hoffman 75 will not be enough for venting the returns, and the baseboards. Tell us what the total pipe length is, and we can estimate your required venting capacity.
Crank down all the inlet valves until they are almost closed, and see if that helps heat up the final rad.
With orifices installed which will be the final solution to be done in the summer, the pressure should be very low, in the 4-8 ounces range. A good low pressure gauge will show you also the back pressure of venting, which should be under 2 ounces, (with adequate main venting), while the system is pushing out the air.—NBC

DuaneK

I have about 60' of 1 1/2" main pipe (boiler left riser to last convector and main vent is 44'). Other riser goes for 16'.
I just opened the 4 baseboard valves a 1/2 turn (3 turns are fully open)

Steamhead

If the original convectors have traps, the baseboards should too. I've always found it best to maintain the same pattern throughout the system, so everything behaves the same.

In this case, the traps could go in the basement, underneath the baseboards where the return lines come down.

DuaneK

Thanks for all the help guys!

The last convector/room was toasty warm this morning! Seems to be working just fine. The kitchen with the baseboards was a little cooler. I'm going to open the valves a little more and try to balance it.
What traps do you recommend I use?

Steamhead

What traps are on the existing units?

EBEBRATT-Ed

He said previously that he had no traps from what I understand. Don't think you should have traps if the system doesn't have any now

DuaneK

Here's a pic of the traps on the convectors

Steamhead

If you're referring to the large hexagonal formation in the top of the convector element, that's not a trap. It's a wrenching surface, to hold the element while connecting pipes.

IIRC, Webster was the only company that made convector elements with built-in traps, but these were cast onto the bottom of the element.

I see something underneath the element that looks like brass but can't make it out. Can you get a pic from the underside so we can see both the pipe connections?

DuaneK

The right side is the supply

EBEBRATT-Ed

I must be blind. I don't see any traps

DuaneK

That's great, I guess I'm good to go! I'll keep everything as is (I was told that they were traps).

Only question remaining is if a single Hoffman #75 is enough for my system.
60' of 1 1/2" main
60' of 1" dry return

nicholas bonham-carter

If it’s a new boiler,hopefully piped in accordance with Burnham’s instructions, then there will be oil inside the boiler which must be skimmed out. Several sessions of several hours are needed.
The Gorton 2 is about the same price as a Hoffman 75, at Supplyhouse, but has twice the capacity, which you need.
Some two-pipe systems had a main air eliminator, (looks like ham, or a paint can), with crossover traps from the supplies to the return. If you have that configuration, and the crossover traps are working, you may not need main vents, unless there is a lot of wet steam.
Letting the air out quickly, as steam is rising, with very low resistance, (back pressure 2 ounces max), fills the supplies first, and then the convectors simultaneously. Why spend extra fuel money to squeeze the air out of constipated little openings?—NBC