Pressure relief valve leaking... any advice?

hot_rod

The chances of a 40 year old, iron body fill valve sealing tightly after being put in fast fill for the first time? Slim to none.

I consider these 3 critical parts to be consumables, replace the whole group for peace of mind Fill, expansion tank and relief.

edsut

@EdTheHeaterMan, well assuming I'm the "OP" (not sure what that stands for), yep you're on the money. I appreciate all the comments, realizing that some may be too little, others may be too much. Every time I've interacted with this forum I've gotten good healthy responses.

@mattmia2, I did receive the tank in less than 24 hours after I ordered it! Major kudos to www.supplyhouse.com!

So I've installed the relief valve (that's the only part that required sweating/soldering). I've got the new tank and air vent in hand and will install them tonight.

The vent is at the high point in my system, so I get that this automatically gets rid of air, but what is the knob at the top for? I assume that just allows me to shut off the vent?

Hopefully this time tomorrow I will have everything back together.

mattmia2

The cap seals off the outlet of the vent. It has to be loose for the vent to work. It will seal off the leak when it eventually leaks.

EdTheHeaterMan

OP = Original Poster

edsut

Ok, everything is installed. I opened up the valves, attached a hose to the hose bib on the return side and turned on the feed. I momentarily opened the PRV fast-fill to allow it to flow a bit faster. I shouldn't admit this, but initially after turning on the feed, hearing water flow and also hearing some air purge out of the vent I was concerned because there was no water coming out of the hose... Amazing what a difference it made after I opened that valve!! (motto: I'm an idiot) :-(
Anyway, everything seems to have settled, so I shut off the hose valve and removed the hose. The feed is on, the two inline valves are open and the air vent remains open. I have a few [hopefully final] questions:

• I adjusted the expansion tank to 12 PSI prior to filling with water, and now I see that it is up to about 13.5. The in-system gauge as well as the 2nd one I attached to the upper hose bib show a pressure about the same. Is that ok?
  
• Do I leave the air vent in the open position all the time (my guess would be yes)?
  
• I'm assuming it would be a good idea to turn the system on heat mode so that the pump engages and the system is in full-running mode for 30 minutes. Any reason not to do that?
  

mattmia2

Leve the auto vent open.

Run the boiler to get the water up to temp and help drive out the dissolved oxygen in the fresh water and move it to the vent.

Not a terrible idea to turn the prv down a touch but 13.5 should be fine.

PC7060

Nice work!

yes to all three! 

Edit: quick fingers @mattmia2 beat me to the post. 

edsut

Thanks to all for the help on this! I saved a few $$ and learned a lot.
Much appreciated!!