Re-purposing Monoflo Branch for Radiant Floor Heat

JWieg727

We recently renovated our kitchen that had baseboard heat in it like the rest of the house. We chose not to put the baseboard heat back as we didn't have any wall real estate left for it to go on after the new cabinets. It's not a huge deal because it's right above our boiler room and doesn't really get much colder than the rest of the house anyway and we conveniently have Geothermal air conditioning so we have a fan that can circulate the heat in the winter. however, I'm trying to think of ways to repurpose the bypassed (currently) loop in the basement to produce SOME warming heat in the kitchen. We have a monoflow 2 zone system that heats the rest of the house. My thought is to use the existing monoflow tee with, possibly, a separate branch circulator and staple up joist trak to run radiant floor heat throughout the kitchen. The idea is that the circulator would help overcome the additional head pressure from the increase in length. I'm curious also if regular boiler temperatures are ok for Radiant floor heat? If not, is there a good way to regulate temp? Could I eliminate the monoflow tee and just use the branch circulator as the control?

This would need to power through about 3/4" original subfloor + 1/2" of plywood + 1/8" of ditra and thinset as well as 1/2" of tile. I haven't done any sort of load calculation for the room. Is there a different site that works like the slant fin site used to?

I searched the forum for this topic and found some useful information but hadn't found much on my specific situation.

Let me know your thoughts. Thank you in advance.

Jamie Hall

You can run the radiant as a completely independent loop, with its own pump and mixing valve, off of whatever primary manifold you have for the rest of the system.

You might get away with using the two Ts from the abandoned baseboard as the takeoff Ts as well, but you will still need the mixing valve for tempering and an independent pump. Note. Might. I'm not keen on this option…

EdTheHeaterMan

If you abandon a Monoflo® tee branch, DO NOT just cap off the two pipes that go the the removed radiator. you will need to run a bypass from one tee to the other tee in order to keep the water flow thru the system as it was designed.

As far as using the tees as the source for the radiant floor heat: you will probably mess up the pressure differential and temperature differential that was designed into that particular branch radiator. You don't want to do that until you have about 30 years experience in designing one pipe MonoFlo® systems. Then do the calculations that the original system designers used to do in order to get the system to be balanced.

here is the information you need to understand to get it correct.

https://s3.amazonaws.com/s3.supplyhouse.com/product_files/108119-Submittal.pdf

https://s3.amazonaws.com/s3.supplyhouse.com/product_files/108119-Install.pdf

https://s3.amazonaws.com/s3.supplyhouse.com/product_files/108119-Selection%20Guide.pdf

https://s3.amazonaws.com/s3.supplyhouse.com/product_files/108119-Reference%20Guide.pdf

just to get started.

If I were doing the project, I would use a home run back the the boiler room for that zone and look as page 24 of this book

https://s3.amazonaws.com/s3.supplyhouse.com/product_files/108119-Reference%20Guide.pdf

Dave H_2

I would not do it that way either. The radiant responds totally different than the exisiting system.

The radiant will want to run longer to give a more slow and gentle heat into the space. Nobody ever asked for radiant heating, they all wanted warmer floors.

Separate it out as another zone to get what you want

rynoheat

How about a kickspace unit under a cabinet?

EdTheHeaterMan

https://forum.heatinghelp.com/discussion/comment/1824025#Comment_1824025

I would do a kick space heater that way. I would do a kick space heater on a 3/4" baseboard series loop with a monoflo® tee. You just need a way to purge the Kick space heater when needed.

JWieg727

Thanks all for the suggestions and references! I've got questions on both options.

Additional zone:

Ok so I'll abandon the idea of using the existing monoflo loop for the floor heating.

1. I'm assuming I would need to tie that into the largest pipe coming out of the boiler in order to prevent starving the other zones?

Kickspace heater:

I hadn't taken much time to look into this one. I've only really seen one that goes under a sink cabinet and blows on your feet. I actually do like the idea of running a new element under the cabinet if it's possible to retrofit after the cabinets installed. I could potentially run a bleeder under the sink. However:

1. Would this achieve heating the space or would it be more localized?

2. Is there an effective way to run a longer element under a cabinet and get the same effect AND without it looking like an after the fact decision?

I think this one deserves more research on my end but any guidance is helpful.

Thanks,

Jake

JWieg727

Oh wow, some of these kickspace heaters output nearly 12000 BTUs. I was seriously underestimating the performance of these. It's possible 1 or 2 of these could easily heat the entire space I'd think.