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Re: What size couple old brass
They used to make adapters to go from Brass to Copper that you could sweat. One end was made to fit over brass pipe.
I think they were only made in smaller sizes and may not be available any longer.
Re: What size couple old brass
it looks like there is a sharkbite designed for pvc that is ips but the outside might not be smooth enough for it to seal.
you could thread it but old brass tends to become brittle so it might crack if you try to do it with a die. a thread mill could probably do it but those aren't exactly portable.

Re: What size couple old brass
the sharkbite is copper pipe size, not ips right? you can measure the od. megapress will fot ips.
here are the sizes:
if it is 3/4" ips the od should be about 1.05". there were also some local brass pipe standards, i think the most common one was used mostly in Boston.

Re: What size couple old brass
a 7/8 acr fitting would probably slip over it and yo could sweat it.
edit:
er, maybe not, i was thinking 3/4 hard copper. ips is going to be a bigger od. you could probably swedge something to fit with the right tools

Re: System 2000, nearly double the cost of Weil McLain, is it worth it?
Here's a brief tutorial on primary/secondary from heating expert @Ron Beck :
Whichever boiler you ultimately choose will come with piping instructions. Some give you options like primary/secondary, or piping the usual way but adding a bypass that gives the hot supply water a "shortcut" to return straight to the boiler, thereby boosting the return temperature.
I will mention that we have two Weil McLain cast iron boilers that were NOT piped according to the instructions (the bypass was omitted) and have been running for 30 years with low return water temps (below 130 F) with no apparent ill effects. So while I am not advocating ignoring the installation instructions, I am saying that, in some cases, low return water temperatures are not necessarily fatal.
Just make sure your installer pipes the boiler according to one of the approved methods in the instructions, and you'll be fine.

Re: HTP UFTC-140W Recurring Error Code 11 Issue
Had a similar problem with a UFT-80, a few years ago.
Error code 11, replaced ignitor, replaced flame sensor. Checked combustion again. No luck. Second trip and a call to HTP
On the UFT, the flame sensor is visual. There are two windows on the heat exchanger, one for the flame sensor and one for visual inspection. First, I switched the flame sensor to the other window which resulted in most ignitions on first try. The glass into the heat exchanger was fogged. Also checked this by shining a light directly into flame sensor.
Hope this helps. The glass is replaceable but I little bit of a job to get to it from the inside

Re: Steam pressure question
It's a one pipe system and no pressure will cause water to stack up. Here's my video that proves it if you are interested. The reason is because the same pressure that is pushing water out of the boiler is also existing at the far end of the main and is pushing the exact same amount in the other direction.
Re: HTP UFTC-140W Recurring Error Code 11 Issue
Before
and after 4 hours of chemicals and scrubbing and scraping on one I did yesterday.
It was having the same issue as yours: intermittent ignition failure.
If you don’t get the heat exchanger properly cleaned and the combustion set up with a digital analyzer, you’re just wasting time and money.

Re: Loud radiators - first “shoulder season” night
So update here - I pitched the radiator a bit more and that helped a significant amount with the gurgling. Still get a little but not nearly as bad.
My radiators definitely have thermal expansion metallic ticks/tings alot more in the shoulder season (likely because of the time between the steam cycles allows the radiators to completely cool. I get the sound both on warm up and while the radiator cools down (though not as rapid/loud on cool down). I assume not much can be done here - have read both tightening and loosening the tie bars - though these are 100+ year old radiators so not really a fan of messing around with them.