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odd radiator connection

Hello all. I've searched for an answer to my question with no luck so I've decided it's time to start a new thread. I'm removing three radiators from my second floor so I can pull up and install a new hardwood floor. My radiator system is defiantly a hot water one and all the radiators in the house look normal except one. Normally both water lines, one going into the radiator and the one coming out, are connected at the bottom of the radiator. However, one of mine has the return line, or what I'm assuming is the return line, connected at the TOP of the radiator. I have yet to come across anything with a similar connection and I don't know if I should leave it like this or change it. The radiator seems to work fine with good heat coming off in the winter and does make any noise.

Does anyone have any info on why it would be connected in this way?

Re: odd radiator connection

Perhaps rather than a return it is a daisy chain feed to another radiator.


Re: odd radiator connection


Our moderator made the excellent suggestion that your under-floor hot water piping system connecting all the rads may be a daisy chain arrangement---this corresponds to the "one-pipe series loop" illustrated in the "high performance" site below, which was designed more for baseboard elements, rather than hw radiators----you can see that water flow in baseboards can only go in one direction with no chance that the hot water will develop "dead spots"---a radiator is another story---piping rads like this can result in dead spots where most rad water is bypassed and the rad remains cold, despite hot water being pumped by the boiler thru the piping system.

Quite often the previous owner of the house had problems with that particular rad not heating up during the winter because air had got trapped in that particular rad & the pumped hot water flow from & to that rad was blocked when an air pocket developed in that particular rad---since all the supply/return piping for the rads is now sub-floor & hidden from view, it can be impossible to figure out exactly how these rads are connected to each other---the "high performance" site below shows the numerous ways hw heating piping can be connected----bleed valves are often installed on either side/top of the radiators so that any trapped air can be "bled out" if a particular rad stops heating---this can solve an "air blockage problem", but most of the standing water in the rad can still be bypassed during a heating sequence, resulting in a cold or lukewarm rad; the bottom/top piping arrangement on a particular rad may improve water flow thru the rad & thus minimize any formation of air pockets or dead spots that will result in a non-heating rad.

The "high performance" site also illustrates the use of "monoflow tees" (venturi valves) in hot water heating circuits, which offers another alternative to the present distribution piping in your system for this particular rad.

The "Caleffi site" site illustrates the numerous components & parts that are used in hydronic (hot water) heating systems, circuit designs, etc.; the posting of this site is for illustration of hot water heating circuits & is not in any way an endorsement of Caleffi products.

If the rad is now heating ok, I would leave it as it is---any alternatives would require you to convert the rad to bottom feeds & install a bleed valve at the top of the rad, which may or may not work.

The "Mighty Greek" Louis Tsalikis has a YouTube video below that explains the intricacies of hw radiator piping, air pockets & all that good stuff.

While at the YouTube site, enter in their search box "Cold hot water radiator" to get additional videos covering this issue.


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