2 pipe low pressure steam

creger.robert

looking to replace Hoffman #8 return line valve -what can I replace it with-also this radiator has a maid-o-mist vent on it -why?-only half of radiator gets hot

delta T

Partial heating of a radiator is normal unless it is in design conditions.

If this is a 2 pipe system, the radiator should not have a vent on it. The Hoffman 8C is a high pressure condensate trap if I am not mistaken, you would most likely need a 17C trap for most residential systems. We really need some more info to answer the question though. Is this residential? What kind of two pipe system (there are several)? Can you post some pics of the radiator in question and the boiler and associated near boiler piping?

Steamhead

You don't need to replace that trap- parts are available to rebuild it from Barnes & Jones or Tunstall.

A Hoffman #8 trap tells me this is probably a Hoffman Vapor system- does it have a Differential Loop near the boiler?

Jamie Hall

Agreed with @Steamhead -- and from the description of the location, it's one of the crossover traps. Don't lose it.

But do lose the vent on the radiator... not needed, and if there is still a differential loop it will defeat the purpose and operation of the loop.

While you're at it, check for traps on radiators on the same return line as the radiator with the vent. One of them may have failed open, or the trap on that particular radiator may have failed closed. Either way, it would need fixing.