momentumep
New Member
I have two Weil-McLain WGO-5 oil-fired boilers supplying 8 zones. One of them was releasing water through the relief valve every night until I, for a completely separate reason, redid all the pipe insulation. I was pleasantly surprised that after improving the insulation, that boiler was only occasionally releasing water, and in much smaller amounts.
I noticed that the pressure on that boiler is often at 40psi or slightly higher, while the other boiler is usually below 20psi. The temp on both of them is usually just under 170. Reading posts about high boiler pressure suggested it might be bad expansion tanks, but the boilers share the same expansion tanks.
Any ideas on why the two boilers have such different pressures and what could be causing high pressure in one of them?
I noticed that the pressure on that boiler is often at 40psi or slightly higher, while the other boiler is usually below 20psi. The temp on both of them is usually just under 170. Reading posts about high boiler pressure suggested it might be bad expansion tanks, but the boilers share the same expansion tanks.
Any ideas on why the two boilers have such different pressures and what could be causing high pressure in one of them?