Leaking Gas Fired Boiler

willasdad

Anybody had any experience stopping a leaking boiler with Fernox F4? Or any other similar products. Buddy of mine asked me to come by and change his expansion tank, no problem. What he didn’t realize was the pressure on boiler had been up to 20 psi for some time, and now the boiler itself has a continuous leak. I took the pressure down to ten and it slowed to frequent drip out of the front of casing. Boiler is between a rock and a hard place to say the least and will require major surgery just to remove the jacket to inspect. So I was wondering if anybody had any experience and or success with these anti corrosive/ sealing products? Thanks in advance!

nicholas bonham-carter

Is this on a hot-water or steam system?
With steam, the pressures are much less, but very hard to seal for more than a few weeks. The product I used 25 years ago was taken off the market by the EPA because of the fumes it generated in the system, which would get out through the air vents.
With hot water, maybe you could get through the season, or maybe not. It depends on the size of the hole, or crack. 20 psi doesn’t sound like a lot to have breached the sections, so the point of failure could have been a crack caused by thermal shock.—NBC

willasdad

Sorry, it is hydronic. And it did seem like 20 would be kind of low to have caused this. Perhaps the expansion tank failed all at once and the boiler took a bunch of cold water, could that be the thermal shock your suggesting? I can’t imagine it’s to big of a breach, as it is literally just a drip, not even constant.

Grallert

I've use Hercules Boiler Weld with good results. It's often gotten a customer short on funds through the heating season or at least given them some time. The stuff is a liquid, mostly waterglass I think. It's not a fix.

HVACNUT

If its actually leaking from a block section, dont waste your time on a boiler seal. It is for a very temporary repair. That stuff will attach itself to the circ impeller, gauge bulb, relief valve, seal the extrol bung. And if the boiler has a tankless coil, forget about hot water.
Replace the boiler.

willasdad

Well I do appreciate the feed back. Kind of what I figured, old egg in the radiator routine, but I’ve been kinda out of the loop for a while and was hopeful for my friend that something had come along in recent years. Can sections be tightened anymore? I remember hearing about sections being put together with push nipples and threaded rod. Are newer boilers even put together that way anymore? Any tolerance to be tightened? It’s a ‘newer’ New Yorker boiler. Unfortunately that’s all I know as he lives an hour and half from my house and I was only able to afford enough time to get the expansion tank swapped and drop pressure. Thanks for the input fellas

HVACNUT

New Yorker is U.S. Boiler.
Get the serial number and see if theres any warranty left.

willasdad

Will do, thank you!