Can I do this to my modcon?

Users who are viewing this thread

Dana

In the trades
Messages
7,889
Reaction score
509
Points
113
Location
01609
A buffer would be a band-aid (and an expensive one, if going with a BoilerBuddy or ErgoMax). Right-sizing the boiler is a much better approach, but as pointed out previously, even with the -050 it'll still short-cycle on the fin-tube zones unless you marry them into a single zone or increase the radiation on each of the small zones.

At 180F out it's probably getting ~87% combustion efficiency. If it's running 180F out at 37% of the -100's max fire that's (0.37 x 0.87 x 100K-in= ) ~32KBTU/hr, and you're already at the highest temperature that the PEX is rated for. If your radiation can't take anywhere near the full output of the boiler without melting, it's dead-certain that it's the wrong boiler, eh? ;-)
 

Dana

In the trades
Messages
7,889
Reaction score
509
Points
113
Location
01609
Our radiant is clip-finned pex suspended under the floor - it heats the airspace beneath the floor so the design temp is 180 deg, a good match for fin-tube. It's a rather common set-up in this area.
Plus, we have alot of large double-hungs upstairs, so the space from the window sill-to-floor is limited making BB's a good fit.

The finned aluminum butterflies on PEX approach to radiant makes some sense if you have an oil-fired cast iron boiler that can't tolerate condensing temps, but is wasting the potential condensing efficiency of a mod con.

Convecting panel radiators come in baseboard-heights if necessary and deliver more consistent output at low water temps than fin-tube. Ten feet of 12" tall panel radiator delivers ~9-9.5KBTU/hr @ 180F AWT, and is still good for ~5KBTU/hr @ 140F AWT. A 10' section of 8-9" high panel is good for ~7500BTU/hr @ 180F AWT. It's more money than fin tube (even the cheaper ones), but it's also more comfort, and capable of reaping lower temp/higher efficiency operation out of the boiler.
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks