In article , treno wrote:
OK, so I replaced the pressure release valve and maybe I broke the
pump in the process. I have a Lochinvar hot water boiler with a B&G
pump heating radiators.

Initially water was leaking out of the pressure release valve.
Sometimes a little, sometimes a lot. I drained the system and replaced
the pressure release valve(PRV). Then I replaced the spicket tht
drained the system because it was leaking too. I started up the system

Hold it right there!!

In between "I drained the system" and "I started up the system" there SHOULD
have been "I refilled the system."

I didn't see that. DID you refill the system??

I ask, because these symptoms...

and it worked fine till a blast of hot water came out of the new
pressure release valve. I turned on the system later and everything
started shaking. Now when I turn on the system the boiler comes on and
the pump comes on, but the pump does not seem to be circulating. Does
anyone have any ideas what I have done and what I can do to fix it?

... are *exactly* what I'd expect to see if you restarted the system without
filling it first.

By the way... chances are, it's not your pressure relief valve that was the
problem to begin with. It's more likely to be the pressure-reducing fill valve
(the one that allows water from the regular plumbing system to enter the
boiler).

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.