Pressure in Boiler is steadily rising

[CP]

I have a two stage Hydrotherm boiler with an everhot indirect water tank for a 3 story building. I had the boiler cleaned and then replaced the drain valve on the steel overhead expansion tank, as well as replacing the water feeder.

I have repeatedly drained the expansion tank down to a trickle of black water. In about a months time the boiler pressure goes from 15 psi to about 22 psi, at which point I'm afraid to let it continue so I drain the expansion tank again. A plumber came by and told me if the coil in the everhot tank even had a pin hole leak, the boiler pressure would go from 15 to 30 psi in an hour, not a month.

Any suggestions, ideas what it could be?

[.p.jm.]

Bullshit.

Did you do what I told you to do last time you asked this ?

[CP]

malrescuesite.com/

I closed the valve before the water feeder and the pressure still rose in the boiler at the same rate over time.

[.p.jm.]

That's nice. Now answer my question.

[CP]

malrescuesite.com/

You said to do the following:

"Drain the boiler, leave the fill to the potable open, and see if your boiler fills up. Remember, water will only move from high presure to lower presure. Your potable is always ~ 60 PSI. "

So, in your example above would I leave the feeder to the boiler open and the potable to the coil open? If so, I believe the boiler will fill to 15 psi and then repeat the pattern I described above, gradually increasing boiler pressure over time.

[.p.jm.]

No, close the feed to the boiler. Perhaps I should have made that more clear.

What you believe is irrelevant. Your boiler neither knows nor cares what you believe. It is, after all, a boiler, and thus not sentient, nor caring in general.

[CP]

malrescuesite.com/

So if I do as you say, drain the boiler to 0 psi, shut the feeder to it and leave the potable open to the indirect tank. How quickly would you expect to see my boiler start filling assuming the coil has a hole in it?

[.p.jm.]

!!!

How big is the hole ? You tell me.

Give it 12 hours, 24 if weather permits.

And do not judge by boiler pressure now, look for the actual water level. Drain it DOWN, not 'to 0 psi', Then watch for 'rising water', not 'rising pressure'.

[CP]

animalrescuesite.com/

malrescuesite.com/

So you're saying, turn off the boiler, drain it completely (boiler pressure will show zero psi), shut the valve to the feeder, leave the potable to the indirect open, and with the boiler off and cold see if the cold water rises in the boiler.

[.p.jm.]

Yeh, that's pretty much what I said.

[Grumpy]

[PaxPerPoten]

It wouldn't fit up there.

[.p.jm.]

Needs more grease, then :-)