trapped condensate

smc

have a steam boiler small hotel it has a lift pump next to it no level control two main traps above it. recently condensate seems to be trapped, when burner shuts off can suddenly hear large amounts returning tends to add water and will overfill. not much surging, ck valve on returns seems to work, and not bleeding through auto fill. can hear some gurgling when starts like might have partially plugged line.
any ideas? cant put my finger on what it means condensate returns when burner shuts off. thanks scott

EBEBRATT-Ed

need more information. Sounds like it's main trapped to me. One pipe system, two pipe system? How is it piped? Do you have radiator traps in addition to the ones at the condensate receiver.

smc

its two pipe with traps at radiators. I didn't see any steam coming out of open vent from lift pump. long returns with clamp a leaks I they are going to replace see if looks like plugged at that time

Jamie Hall

If the traps at the radiators are working, one does have to wonder what the two main traps are doing... besides possibly causing problems. You may have to rethink the main and returns plumbing. No telling what has been added, never mind why.