Any Drawbacks About adding Second Pressure Relief Valve and with Vaporstat

nycpa

Are there any drawbacks about adding a second pressure relief valve along with a vaporstat for a steam boiler? Would prefer redundant safety features in case the primary ones fail. Currently I have the regular pressuretrol and 15psi safety pop.

BobC

No reason not to but for good redundancy use a different boiler taping so one clog can't disable both PRV's.

Bob

Jamie Hall

A vapourstat in addition to the pressuretrol is a fine idea. You can use the pressuretrol (set to say 3 psi) as a backup safety. And even better idea is a manual reset pressuretrol, but you'd have to buy that. (That's the setup I have -- vapourstat for actual control, a secondary pressuretrol set higher, and a manual reset pressuretrol set higher yet).

As to the second PRV. No reason not to add one, but be absolutely sure that the boiler tap it is on is big enough. Never use a small tap for a PRV. Otherwise you might just as well not have it.

Fred

If you add the Vaporstat and keep your Pressuretrol on as the secondary (backup control) you will have redundancy at the safetrol control level. If the Vaporstat fails, the Pressuretrol will still manage the pressure. Make sure these controls are on seperate pigtails to eliminate the risk of a single pigtail getting clogged up and preventing either device from working. If you do that, I really doubt you will see any benefit from adding another PRV as those controls will never let the boiler get to the 15+PSI needed to trigger the PRV.

nycpa

Thanks for the Advice guys.