Monoflo System reversed supply/return

cchhat01

Hi,

I'm not very knowledgeable about my heating system, but over the last 24 hours I have accumulated a wealth of knowledge just by searching and reading the interwebs. Please bare with me for the below and correct me where I may be wrong.

I have a monoflo system and I believe the loop itself is 1 inch pipe. Each of the rads is on the main floor, boiler in the basement. Rads are all floor mounted semi-recessed enclosed sterling/beacon-morris style convector heating elements with an arched inlet and louvered outlets (no damper). Most have with 3 copper tubes with aluminum fins and brass headers (not sure if they are single or double headers for top or bottom install, but it shouldn't matter). Smallest being 24 inch in length to longest being 48 in length, each being 6 inch deep. I also have one larger rad which is about 64 inch in length and the convector heating element on that has 4 copper tubes, this being 8 inch deep. Lots of rusting on the brass header on some but we'll get to that later. Also the kitchen has a baseboard installed. Boiler is Greenstar Combi 150K. It was put in 1 year ago.
Here is the clockwise view of the system:
Boiler -> Master Bedroom -> Study/Temple room -> Living Room Large Rad -> Living room smaller Rad -> Kitchen Baseboard -> Bathroom -> Guest Bedroom -> Boiler
(Counterclockwise, reverse the direction of course)

Each of the rads has an inlet valve (round knob) located on the bottom left going into the header and a bleeder vent located on top of the right header (from which I believe the water exits into the monoflow loop below). So if I were to assume, the flow of water in the monoflow loop SHOULD BE clockwise if all the rads are chained together around all the corners of the house. It is difficult for me to tell whether the tees to/from the monoflow pipe into the rads are diverters or not.

The rad that doesn't warm up at all (study) has a broken valve control (round knob) and the most amount of rusting around the headers. However, I used a wrench to turn the valve fully counterclockwise to have it in the fully open position. I have also bled all the vents and air did leave and water starts to spout out (so I no longer have banging noise). The valve end of the rad I can feel is hot very very slightly. If I bleed it more (just remove some water from vent), I feel the vent end of the rad slightly warming up for a couple of minutes but it never ever gets warmer if I stop this process.

What I also noticed is that the rads that do warm up tend to run hotter around the areas of the vent and less so around the valve. This is what is making me lean towards the hypothesis that the flow of water is reversed in the system.
In all, I have 2 rads that barely heat up (master bed and study). Both are closest boiler in the clockwise flow (last two on the counter-clockwise flow). The 1st rad on the counter-clockwise flow (guest bedroom) is boiling hot, so is the 2nd (bathroom). all the way up until the Large living room rad (but not so hot as the first).
What can I do to determine why some rads do not warm up.

Thanks for the patience.

EDIT: Added pics of the boiler and pump/piping and a sketch of the connections

the_donut

Some pictures and a system sketch would be nice to visualize the system. Near boiler piping, expansion tank, pumps, connections to problem radiators and pictures of the loops themselves.

JUGHNE

Can you see the Tees in the basement?
There would be 2 for each unit, the monoflow tee may have an arrow or a ring groove on one end.
Pictures please.

EBEBRATT-Ed

Pictures will help. I suppose it's possible when they installed the boiler they reversed the piping.

the_donut

Or the supply side of tee is plugged up.

cchhat01

Sorry took a while.
All the Boiler pics are for things around the boiler. I tried capturing as much as possible. If more is needed, let me know and I will try to get as much as I possibly can.
The Bath Rad pics indicate the same rad. The pipe to the right is the one connected to the "vent" end and the one on the left is connected to the "valve" end.
The Master Bed Rad pics 1&2 are the same bedroom rad for the end which is closest to the boiler as described above (one with the "valve" connection). Everything else is unfortunately closed up as a result of the basement being finished. The only tees I can potentially see are the ones which belong to the bathroom rad and to do so I'd have to rip out the taped insulation.
I wish this would have been done before the basement was closed up. Worst case scenario is that the a tee which I no longer have access to is clogged. Shame on me for not knowing my own home's heating system better.

I hope this is a good starting point for experts here to give me some guidance.

I'm willing to purchase the replacement parts (convector heating elements with valves and vents, tees, pex pipe for the loop, etc) to get this sorted out. I only hope to get the right info so that I can go back to the contractor and have him get this done while he's down there doing the basement.

Thank you.

EDIT: Basement is going through hell so there is some dirt around the boiler which I will cleanup eventually

cchhat01

Adding sketch of of the layout of the rads in relation to the boiler

the_donut

I would also try turning the problem radiators off, then back on a bit. Looks like pipes have been replaced a few times and are all kinds of sizes. It could be that radiators had orifice and valve needs throttled because water is zipping through bottom and not rising to top.

cchhat01

the_donut said:

I would also try turning the problem radiators off, then back on a bit. Looks like pipes have been replaced a few times and are all kinds of sizes. It could be that radiators had orifice and valve needs throttled because water is zipping through bottom and not rising to top.

The valve on the problem radiator is stuck. Any attempt to get it unstuck through the through wrench/pliers does nothing. I can feel the location where the copper going into the header just stops getting warm and its around the valve.

Also the pipes are the same size. 1 inch in and out of boiler and to the loop. and each tee that leads to the rad and back is half inch.

JUGHNE

Did this heat OK before the new boiler??
If so then the new boiler installer should figure it out.

If you can expose a set of tees for a single convector, it may tell you which direction the water should flow.

You may have an air lock up somewhere.....also the installers duty to fix.

If most of us here did the install our phones would not stop ringing.....what does he/she say?

SuperTech

I have thought about the possibility that my boiler was installed backwards, but finding the diverter/monoflow tees doesn't reveal everything. My monoflo tees are on the supply side the system, with the arrows pointing in direction of flow. But I have also read that they can work piped the opposite way. Diverter/monoflow systems are a different animal....

JUGHNE

Can you show us the arrows on the tee and the other tee connected to that heater?

SuperTech

Here you go. I have another thread about my system, I've been trying to figure out the details about why it is the way it is.

JUGHNE

I was actually asking the OP about his tees.

But yours seem obvious....."inlet".....arrow.....1/2" branch on the fat/bigger part of the tee to induce flow up??
IDK, could you turn them around to pull water out of a heater??

Not familiar with that type, someone here should be.

SuperTech

I've been reading the heating history section on diverter tee systems and the more I read the more I question.

No one really installs diverter tee systems anymore. And it seems like no one has in a long time. I think all men who did this work are long gone.

the_donut

> @cchhat01 said:
> I would also try turning the problem radiators off, then back on a bit. Looks like pipes have been replaced a few times and are all kinds of sizes. It could be that radiators had orifice and valve needs throttled because water is zipping through bottom and not rising to top.
>
> The valve on the problem radiator is stuck. Any attempt to get it unstuck through the through wrench/pliers does nothing. I can feel the location where the copper going into the header just stops getting warm and its around the valve.
>
> Also the pipes are the same size. 1 inch in and out of boiler and to the loop. and each tee that leads to the rad and back is half inch.

Are you sure the radiator valve is open then? Try spraying a little penetrating oil on packing nut and loosening packing nut a quarter turn. Then try turning the handle in either direction. If handle is spinning, but shaft isn’t, tighten fastener. You can repeat, but I wouldn’t take packing past half a turn.

EBEBRATT-Ed

@SuperTech , many here understand diverter or monoflow systems. There's nothing to it but a little engineering...same as any other system.

If you really want to fix it you have to start from scratch and do the work.
1. heat loss estimate
2. size radiation
3. place radiation
4. make piping layout
5. size piping

Skip a step it may not work.

Many good books on the subject on this site as well as older Taco & B & G books available at used bookstores.

SuperTech

You are right. I skipped the first few steps because I have never been good at math. I've only seen a couple of monoflow systems and they were simple one pipe series systems, mine is nothing like it. But in order to make sure everything is correct I need to do steps one and two.