I have a three zone hot water boiler based heating system. The boiler is currently at one end of my ranch style house. The radiators appear to be directionless (no valves or anything). One of the zones covers approximately half my house and it goes LR/DR->Family Room->Master BR then back to the boiler. The MBR is already a cold room for a multitude of reasons (above garage, low radiator to room size ratio and 2 exterior walls) and we are never in the LR/DR but in the current setup it is always significantly warmer than the Family Room (room we are in the most and the location of the thermostat) and Master BR.

Would it be possible to drain the zone and reverse the in/out pipes so the flow reverses to MBR-> FR ->LR/DR?

I feel like this would work better than using remote sensors with a smart thermostat (I am installing an ecobee anyway for easier control) because the remote sensors would just force the heat on more to make the Family Room and MBR more comfortable while the LR/DR would be sweltering and wasteful.

Below I added a picture of the current valve setup, piping example and the input side of the boiler. I definitely have a single loop setup and I realized the zone goes LR/DR->MBR->FR (or so I hope).

I think I may follow some of the advice and just add a new zone and split the LR/DR off. I need to do some digging because the MBR is over the garage and the pipes are inaccessible without tearing out the garage ceiling but as long as I can find where the pipe goes I can splice it.

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  • I know my house has a "monoflow" hot water system where there is a single loop with monoflow tees. This kind of system is definitely directional...
    – kgutwin
    Oct 18, 2018 at 13:50
  • I will double check tonight but after doing research into single loop vs monoflow, I am 90% sure that I have single loop because there are no tee's at the radiator. The hot water pipe basically travels along then goes up into the radiator and out the other end and back into the basement for the rest of the run.
    – salisboss
    Oct 18, 2018 at 15:12
  • "Radiators" or "fin-tube baseboard"? The latter typically has air flaps that many owners don't seem to understand - you close them partially or fully in rooms that trend too warm, and open them fully in rooms that trend too cold to help balance the heat output of a particular loop.
    – Ecnerwal
    Oct 18, 2018 at 15:51
  • @Ecnerwal I have fin-tube baseboard. I have already adjusted the flaps but the zoning was done poorly in the first place.
    – salisboss
    Oct 18, 2018 at 17:22
  • "because the remote sensors would just force the heat on", not with an ecobee. You can tell the thermostat which sensors to use, and even to ignore the one built in to the thermostat.
    – longneck
    Oct 19, 2018 at 14:44

3 Answers 3


If the radiation is finned tube and you can access the piping from below, you could break-up or split that run in half by running another supply or return connected to the near middle of the run and/or add finned tube radiation in the colder rooms. If you are going to redesign the heating system why not zone some or all the system. You need to answer a few questions such as how the radiation is piped (single loop, mono-flow, etc). There is a lot of possible fixes depending upon just how the system is presently installed. Let us know and add pictures if you can.


Assuming that:

  • No flow-checks are in the line except for what's at your furance
  • The zone is one long pipe with no splits (monoflows like kgutwin said)
  • Its normal baseboard along the bottom of the wall

Then yes, you should be able to do that. You'll need to make the changes after the flow check value on the feed side and circulator or zone value on the return side. When I say 'after', I mean from the point of view of the boiler. So, boiler-> flow-check or circulator/zone value -> rest of pipe to zone (make changes here).

That being said, the best idea might be to remove the MBR and FR from the current loop and make them their own loop since it appears that the loop is far too long anyway. You'll need additional equipment in order to add a new loop (circulator/zone value and related electrical equipment, flow-check, thermostat, etc) but in the end, it will make for a more comfortable home.


It doesn't look like you can easily reverse the piping system. Series radiator piping is a poor design choice for piping in rads. It's beyond me why anyone does it. Some unconventional methods for cooling a room that is too hot is to cover the radiators with an insulating material.

  1. In the case of baseboards that are not controllable by an air shutter, seal the openings with tape or stuff something in the opening to restrict air flow. Most baseboards are primarily convectors. Remove the convection currant and you remove much of the outflow of heat.

  2. In the case of cast iron rad. Covering it with a decorative wooden box reduces it's ability to radiate heat and thus lowering it's heat output. Even simply throwing a heavy blanket over it's helps. Also not bleading at of the air out of cast iron rads effectively reduces their capacity simulating a lower output radiator.

  3. Placing furniture in front of radiators reduces their output slightly. Don't do this with delicate or antique furniture as it will dry it out.

you could do something like this with less opening enter image description here Freshhome.com

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