Old radiators leaking

bricksea

Hello all, I am hoping to get some advice on a project that I am working on. It is a house built in 1910 that had an old gravity hot water system. The foundation was replaced and the boiler demolished before I was involved with the project. I hooked up all of the lines to the existing radiators and pressurized the system with 45 psi of air. After I chased leaks at the packing nuts on the radiator valves I was able to get the system to hold pressure on the gauge before I left the job at 3pm with instructions for the homeowner to monitor the gauge. By 10pm that evening the gauge had dropped to 39psi. By 10 am the next morning it went to 17psi and by 8pm the following day it dropped to 7 psi. I am at a loss how much I should worry about this level of pressure loss. Should I fill the system with water and hope for the best? I have no access to most of the existing piping without cutting open the walls. I used soapy water on my new connections to verify soundness so I am confident in those connections. Any advice that you can offer is appreciated.

JUGHNE

Water is thicker than air. You might never see a water leak.
It held pretty high pressure for 7 hours. You would hear a serious air leak.

Was the house/system ever subjected to freezing? Probably not or that would have shown up quickly. IMO

I would think that others here could offer more experience.

bricksea

Thanks for the help. That was my thought about it. I will hook up a temporary lower pressure water source to verify nothing sprays out. I don't think hitting it with city water pressure would be a good idea, the system is 100+ years old. It's not been frozen to anyone's knowledge. The leaking is not noticeable with soapy water but I don't have access to all of the fittings.

Jamie Hall

Don't hit it with city water pressure! The maximum pressure the system should operate at is just enough so that you have 5 psi at the highest radiator. No more than that. There is no need to test it at anything over that.