Hoffman 74 -vs 75 -vs- Gortoin #2

James Bates

On the previous thread "Steam Vent Calculation" I incorrectly called out the lime green vent as a Hoffman 75. The one in the picture attached is in fact a Hoffman 74. This is listed as a "Hot Water" device. This has been replaced with a copper colored Hoffman 75 which I verbalized in the vent calculation thread. This services two aprox 45 foot 1 inch return pipes on Trane two pipe system. The problem I observe is when system first starts there is large volume "whooshing" air rushing out this Hoffman 75 return vent. Does this indicate the vent is a bit undersized and needs to absolutely be changed to the Gorton #2 that Steamhead called out in the previous vent calc thread??? It is a brand new vent. Hate to change if not necessary. Alfred/Jim

RonWHC

See how well

the system works w/ the 75. The 74 is a steam vent. However, it is designed for higher pressures than the 3# maximum recommended for the 75. A 74 should not be used on residential systems. If the 75 does the job, keep it.

Steamhead (in transit)

The #74

is, as Ron says, not suited to residential systems due to its extremely small port. The similar-looking water vent is the #79.

If you want, change the vents on the steam mains to Gorton #2 and see if you still get that "Whoosh" from the Hoffman. Continue to listen for the whoosh after the Gorton #2 steam main vents have closed, at that point the Hoffman will be the only open vent in the system. If it whooshes, change it to the Gorton #2.

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James Bates

Thanks Steamhead, sounds

like a plan. Will install two Gorton #2s one in each mains leg, listen and if whooshing air is mostly minimized or gone then "SUCCESS".... :-). Thanks for all yout help. Alfred/Jim