Mono Flow Tees

BrooklynMike

I have a 1955 Cape Cod with a mono flow hot water heating system. Previous owner did some remodeling and there is a kitchen/family room with 33' of 3/4" baseboard radiators with a total loop of about 75' There is a regular tee on the supply and a mono flow tee on the return side with about 5'of 1"copper pipe between them. Is this providing adequate flow to the baseboards ? IF not , should I add 2nd mono flow tee to the supply side to increase flow or put the baseboards on a separate zone directly to the boiler. This room is cooler than rest of house due to windows, doors, etc.

HomerJSmith

Are you sure that there is 1"copper pipe between them? So is the supply and return to and from the boiler 1"? That doesn't make any sense to me. 3/4" copper is about 7/8" over all. Are these true B&G Monoflow tees and not cheaper diverter tees?

Basically, if the radiation is above the water supply and return use one tee. If the radiation is below the water supply and return use two tees.

The flow thru one part of a loop, the flow is the same thru any other part of the loop. 4GPM supply to a radiator, 4GPM must return from the radiator. Diverting 2GPM to the radiator then 2GPM will flow to the Monoflow tee to combine into 4GPM at the outflow of the tee. The regular 3/4" tee at the supply side of the radiator will only pass 2GPM regardless of the size of the pipe because of the design of the Monoflow tee. The Monoflow tee is designed to divide the flow. Of course, the flow thru the baseboard is dependent upon the resistance of the baseboard as to flow between the tees.

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

HomerJSmith

The 33' of baseboard isn't one length of baseboard but a combined length of many smaller baseboards with many Monoflow tees? You say "BASEBOARDS" so I assume more than one.
If one length of baseboard, I would use two Monoflow tees because of the resistance in such a long baseboard. With a baseboard that long you would probably run out of heat energy by the time you exit the baseboard. Just spit-balling here.

mattmia2

What are the other emitters in the house, are they also fin tube baseboard?

BrooklynMike

There is a 1 1/4 copper pipe from the boiler at one end of the basement to the other end in the middle of the basement where it divides into 2 1" copper pipes that run down the right and left side of the basement and merges into a 1 1/4 inch pipe at the boiler return. All the monocle tees and regular tees are 1/2 inch for the fin tube baseboards in the rooms above. The only exception is the living room which has a 3/4 monocle tee for a long loop of baseboard about 22' long. And we have the kitchen/family room which has the 33' of baseboard which is one continuous series loop about 75" between the monocle tee and regular tee. Homer J Smith 's second reply answers my question about adding a second monocle tee to overcome the pressure drop in the baseboard loop.

BrooklynMike

spell check is giving me monocle whenI type mono flow. You get my meaning.

mattmia2

if you have access from underneath it might be better to feed it with 1" in the center then bring both ends back to the main in to another 1" tee or 1" monoflow tee

mattmia2

oh, i missed the part of 1" between the tees. that is to force more flow to the baseboard by putting more restriction in the through section.

a separate zone off the boiler is another option if the heat loss of that area is very different from the rest of the structure

but my main question was if the rest of the house was fin tube baseboard. mixing baseboard and cast iron or even panel radiators on the same zone is very hard to impossible to balance because they heat very differently but you don't have that problem

BrooklynMike

Just to clarify, I have 5 feet of 1 inch copper pipe between the supply tee and the mono flow tee on the return. as to baseboard radiation, the house has 1955 vintage steel fin tube radiators in steel cabinets on the wall at the floor line. The room in question was remodel in 2010 and has a mix of older steel fin tube and modern slant fin with the return running in the same cabinet as the fin tube because part of the room is on a slab with no access from underneath.

BrooklynMike

Yes, I am considering a separate zone for this room because heat loss is great than other parts of the house due to more windows, more doors , adjacent to unheated garage and vaulted ceiling to the roof line.
Questioning if I should replace baseboard with high output slant fin units. Do I want higher BTU outputs or longer run time with standard output baseboard. Probably depends on heat loss rate rather than just heat lost

mattmia2

A heat loss calculation will tell you if you can heat the space with your existing emitters. It is likely you can but you will have to figure the average water temp for the whole loop to figure the output of the baseboard. Longer run times are better, will make the heat more even as long as the heat loss and emitter output shows the output is adequate.

Another zone or changing to some panel radiators or something similar that can get more output from the existing supply are probably your best options if you don't have access to split the baseboard in the addition.

hot_rod

Diverter tees add a huge amount of pressure drop. Any modification to the original design can throw the whole system in to a crisis.
How many total tees?

BrooklynMike

Hod Rod,

There is a 1 1/4"supply that runs from the boiler at one end of the basement to the other end where it splits into 2 1" copper pipes that run on the right and left side of the basement back to a 1 1/4" return to the boiler One side has 4 mono flow tees and 7 on the other side . one side has a 3/4 mono flow tee for the kitchen/family room and the other side has a 3/4 mono flow tee for the living room. All other mono flow tees are 1/2". Adding a 2nd mono flow tee to the kitchen/family room side should not mess up the flow rates .

BrooklynMike

Hot Rod,

The kitchen/family room side is the one with 4 mono flow tees. i would be adding a 5th mono flow which should not effect the flow rates too much.