Existing monoflow to reverse return

pauliewalnutz

I have a 1.5 story cape home on 1 zone with an unfinished basement that I plan on finishing, so I'd like to add some emitters to my first floor  and the new basement. The house has 4 recessed convectors and the rest is fin tube. I am planning on adding a 2' section of fin tube at the front entry and a toe kick heater in kitchen. The basement I plan on adding roughly 15' of fin tube. 
- My system works well as is but 2nd floor gets hot. Thermostat is on first floor. 
 I like the idea of reverse return and having thermostatic valves on 2nd floor.  Any issues with having emitters below the main on reverse return? Do I need monoflow tees to force the water down? 
Will toe kick heater need monoflow?

Jamie Hall

The existing system is a monoflow system? And you want to convert it to a reverse return system? No particular reason why you can't do that, but you will need to do some rather significant repiping at least in the basement level, and possibly higher levels depending on just how the monoflow system's single circulating line is piped.

Basically, all the radiation takeoffs will need to have the monoflow Ts removed, if they are on the feed lines. All the returns will have to be separated from what will become a supply main and attached to a new return main (again, no monoflow Ts remain). Additional new radiation -- such as the toe kick -- can be piped in the usual way fed from the supply main and returning to the return main.

But honestly, if the existing system is working well, I'd leave it alone and just pipe new radiation as reverse return. That doesn't solve the overheating problem on the second floor, though...

EBEBRATT-Ed

leave the monoflow as is and use trvs on the second floor. Add your new radiation and kick heater using new monoflow tees.

Pipe the basement any way you wan't. It will be a small zone so you could use direct return or reverse return

Alan (California Radiant) Forbes

I like the idea of reverse return and having thermostatic valves on 2nd floor.

I like it, too! Get rid of the Corvair for the Cadillac. Monoflow system problems are a constant topic here on HeatingHelp.

Any issues with having emitters below the main on reverse return? Do I need monoflow tees to force the water down?

No problem; Monoflow tees not required.

EBEBRATT-Ed

What @Alan (California Radiant) Forbes said it fine if you can afford the Cadillac. You basically going to repipe everything

pauliewalnutz

So I should have said that initially, I plan on repiping since the main that runs in the basement perimeter is pretty low and a fair distance off the wall, probably about 6'-2" off the floor and 18" of exterior wall. So I want to run pex through the floor joists to raise that pipe above the new ceiling. The supply and return from each convector and fin tube are 1/2 " and easily accessible. 
My thoughts on the reverse return was that I might be able to keep everything on one zone still not worry about adding any circulators and getting a new relay and not have to pull wires from the 2nd floor.

EBEBRATT-Ed

@pauliewalnutz

Here's the thing. If you are going through all this trouble to re do the system don't take a chance on it not working.

I wouldn't use TRVs on the second floor they are ok to try and fix a problem job but why not fix it once and for all. Pipe the second floor as it's own zone. If you don't you will regret it and it's not much more work. I am sure the second floor monoflo drops originate from the basement so you can pick them up their.

Unless your house is huge I wouldn't bother with reverse return especially on the second floor

It's not that hard to get a stat wire to the second floor. Put a zone valve for the first floor and one for the second floor use the existing relay and your all done you only need one pump.

Make sure to buy zone valves with end switches. Use the Taco zone valves some of the others have a high pressure drop.

Measure up your baseboards , kick space heaters etc and we can help you size the pipe etc.

pauliewalnutz

Sounds like a good idea with the zone valves. If I run the first floor and basement on one zone that's a monoflow and my 2nd floor a series loop, will I have balaNcing issues when both zones call for heat?
 The existing 2nd floor has 3 rooms all with fin tube piped in series and at the end of the series the pipe is fed from mono flow tee in basement. At some point changes were made upstairs and the supply and return for each individual fin tube to the main was deleted and  tied together in series.

pauliewalnutz

EBEBRATT-Ed

Any zone that heats differently needs to be it's own zone. The basement will heat much differently than the 2d floor and they both will heat different than the first floor.

pauliewalnutz

Update. Ended up switching my plans all together and went with a manifold . Installation went smooth and only had the heat down for a couple hours.

psb75

Interesting that there was no mention of "homerun manifold" option in this thread before you chose this option. Why all the perseverating about monoflow T's and reverse return etc.?
All in all. Good decision. Nice work. Sure is easy with 'the pex' and 'the press'?

pauliewalnutz

I needed to move piping as I am in the process of finishing my basement. I want to Sheetrock the ceiling for the most possible height. My house was on one zone heating for 2 floors. Heated unevenly. Instead of just relocating the mono flow I explored other options and decided I liked the Homerun with manifold and all piping coming to the utility room. I went with the caleffi and experimented and balanced the system to the point were I am able to get the same temp upstairs and on the main floor. The piping was always going to be pex , and I am a union pipe fitter so I borrowed the press gun from my shop. 

jumper

This is an interesting thread. OP does not say how old his place is.There's nice homes with good heating systems that are due for repiping.

pauliewalnutz

jumper said:

This is an interesting thread. OP does not say how old his place is.There's nice homes with good heating systems that are due for repiping.

Built in 1958 . 

Peter_26

Is that hePEX?

SuperTech

I like this solution. In my home I have a system with diverter/monoflow tees. It's a split loop design that was converted to two pipe reverse return somewhere along the way. It works great and I like the additional buffer provided by the water volume but the return piping does take up some ceiling space that would cause a problem if the basement was completely finished. A buffer tank and manifold piped in reverse return will probably be added eventually. 

pauliewalnutz

Peter_26 said:

Is that hePEX?

Yes . The uponor was great to work with.