Heating Help

Myson 7000 toekick heater

I'm trying to install a toekick heater in our kitchen. we have an oil-fired boiler and baseboard heat which is a one pipe loop. (3/4") Kitchen is being reno'd and I removed about 10 feet of baseboard, (bypassed it in the basement keeping the loop correct)  to fit some pantry cabinets flush to the wall, and I'm trying to install the toekick heater in one of these pantry cabs. I followed the directions, and installed a monoflow tee on the supply side and a regular tee on the return and made sure the return is 12" from the monoflow tee. (photo attached). The unit is only a couple of inches above the main line.
My problem is that the hot water doesn't seem to be flowing through the unit. the unit is always cold, although baseboards both upstream and downstream are toasty hot. The pipes going through the floor just before the flexible hoses are hot. I have isolating valves at the end of the flexible hoses that attach to the unit. I removed the unit, opened each valve into a bucket, have great pressure, and very hot water. when I hooked it back up, opened the valves and bled the air from the unit, it got hot for a minute, but not long enough for the fan to kick on, and then cold again. I was able to manually run the fan by switching to summer setting. I've tested the thermostat by heating the coil pipe with a lighter and it does kick the fan on when hot. I just don't understand why the water is not moving through the unit and what can be done to correct it. someone mentioned putting a shutoff valve on the main between the supply tee and return tee to force the water through which is a good idea to test it but I know I can't leave it closed or the downstream baseboards will be starved. Any ideas or suggestions will be appreciated.   Thanks.
 

Toe Kick:

That should work.
I never install a tee in a mono-flo loop on its side. Only in an upward position. In spite of what the instructions may say, if I install a toe-kick on a series looped circuit, I always put the tee on the return.
Are you sure that you have the flow correct? That shouldn't make a difference except that with B&G monoflo fittings, you have the groove that makes it so you always know where to put it because the groove has to face the other tee, no matter whether it is on the supply or return. And a change in flow direction doesn't make a difference.
By going off on the flat, you may be forcing an air pocket into the coil and when you purge, it is only coming through the tee that is in the vertical.
Strange things can happen.
An acceptable solder job. Nice to see a lack of "grapes" on the fittings and pipes. A rag is a wonderful thing.
Hint. Buy a spray bottle like you would spray your plants with. Fill it with water and spray it on the wood before you solder. Especially the rotten spot on the floor where the pipes go through. Soak the heck out of it. While the fittings are heating up, the wood has to heat up and steam the water off. And if you have any "embers" glowing, you can spray them out. "Third World Fire Extinguisher". Of course, if you use a Bernzomatic blow torch, you really need it. You don't get that with a Presto-Lite or air-acetylene like you do with air-propane.

Toe kick

Thanks to all for the ideas and suggestions. The instructions did not call for the return tee to be on its side. That was my idea to keep things "neat and orderly".
I'll change that so the tee is upright.
The arrow on the monoflo supply is pointing in the direction of the flow in the main.. This seemed to make sense because the input side of the monoflo is split so half the water is diverted into the top of the tee.
If I switch the monoflow tee to the return side, or add a 2nd monoflo to the return side, I assume the arrow should point against the flow, or, point at the supply tee.
I think the first thing I'm going to do is try swapping the lines at the unit just to see what happens. If nothing new, then I'll reverse the tees. I can't get to any of this until Sunday, so I'll post my results on Monday. Thanks again.
-Tom

Dont you put the monoflow tee.....

in the return?  And if that doesnt work, both supply and return (fpr a toekick)?  Would a globe valve between the 2 tees work, something you could throttle to force flow into the toekick? 

Hmm

I think that the monoflow tee should be pointing against the flow if it is installed on the supply as you have it. Ideally it should be pointing the way you have it now but on the return. This is the reason you are getting no flow....

Toe kick

A toe kick heater has much more restriction then 10 feet of baseboard.

Spread the distance between the tee's to more like ten feet, and you'll be fine.

Air vs. Pressure Drop

When push comes to shove, I don't think it's an air problem and I think furnacefighter15 and others have hit it on the nose.  Water coming into the tee sees the pressure drop on the branch and decides it's easier to go straight, bypassing the toe kick heater.  Whatever you can do to increase the pressure drop on the run will make it work:

- Increase the distance between the tees.
- Replace the return tee with another venturi (pointed in the opposite direction) so that you have two.

Kink in hose

You mentioned flexible hose, make sure it wasn't kinked when the unit was slid back in place. Also , I would solder in a 1/2 inch ball valve  on  the right side of the horizontal pipe , and a 1/2 inch tee with a boiler drain screwed into the branch. To purge just close valve , purge with drain , open valve and you're done. If there is poor flow with the valve closed but good flow when open there is a reason.

Working Toe Kicks:

I have NEVER in my life, had a toe kick heater not work. Whatever is wrong, has nothing to do with how it is piped with the exception of the tee on the side. Those Taco "Scoop Tee's" can be problematic. B&G's have a groove in them. As long as the groove is facing the other tee, it is always piped properly. I have NEVER seen anyone install a throttling valve between the tees. It isn't needed. Pull the unit out and make sure that the hoses aren't kinked.
I have installed Mono-Flo's on the side and they worked fine. They may work better rising on a 45 degree angle or verticle. But if that was a B&G, and the groove was facing the other tee, it would be working. If the flow is going in the direction of the arrow, and it is on the supply, it will work better on the return side. But it still should work. I just find that the B&G's with a venturi orifice just works better.
But there is no reason that the heater isn't working properly. There is another problem.

I had a problem...

once where the boiler did not have a good airscoop/ air scrubber and the toekick heater would work for a time ...then not. The air kept getting into that loop and air locking it ... I like the simple 3/4x1/2x1/2 approach.