I am in the market for a new oil boiler and the first two contractors quoted the following: Weil Mclain WTG03 and a Peerless WBV-04. Is one better than the other? Is there another brand to look at? I know nothing about boiler brands/styles. thanks!
(What is that comment below?? It makes no sense).

Contractors are not as a matter a fact as first as they are archaic

I have a Peerless hot water boiler, it’s about 8 years old. It has a max psi rating of 30 lbs. PSI. When the boiler would kick on, the water pressure would rise and water would gush out of the relief valve on the back. I adjusted the water pressure regulator (Looks like a bell) to where when hot, it’s at 30 lbs. but when cold it’s at 0 PSI.PSi Is that right. Now, when it kicks on, the water pressure gets to 30 and that’s it. Could the expansion tank be bad. Should it be 30 PSI when cold? HELP!
I replaced the relief valve in the rear by the way.

I presume you are talking about a sealed system. There is a water feed to it with a valve to fill it. Under normal operation this valve should be turned off. if it’s on you will get water running from the pressure release valve.

The heat works but no hot water in shower+sin

Your Peerless Boiler is making domestic hot water from an internal coil. An aqua stat if operating correctly safely controls the temperature of your hot water and this electrical control can be adjusted to maintain the demand for hot water. Link @ Homelinepros.com.