Pipe sizing same for convector versus baseboard

[Al S]

Setup:
1" monoflow trunk feeding semi-recessed convectors through 1/2" pipe.
Monoflow tee on supply side
Monoflow and return tee is 1 x 1/2 x 1 - that is, the center port is 1/2"

High output baseboard is replacing a convector. The pipe diameter of the element is 3/4 inch.
Question:
Is replacing the monoflow and return tee with 1 x 3/4 x 1 tees appropriate? Otherwise, the 1/2 inch nipple on the existing tees would then feed into the 3/4 inch baseboard element.

Thanks

 

[John Gayewski]

Yes replace the tees. Install a trv or ball valve on the supply to control the flow to the baseboard. Also install a valve between the two new tees to facilitate filling and bleeding. This will also help you if your two new tees are too close together you can partially close the valve to steer flow into the baseboard piping.

 

[Sponsor]

 

[Al S]

Yes replace the tees. Install a trv or ball valve on the supply to control the flow to the baseboard. Also install a valve between the two new tees to facilitate filling and bleeding. This will also help you if your two new tees are too close together you can partially close the valve to steer flow into the baseboard piping.

Hi and thanks for commenting. Since the elbow connecting to the supply side is pretty low to the floor, can you suggest how to connect a TRV? I mean on a panel rad, the TRV mounts a bit higher.
Thanks

 

[John Gayewski]

Well you can mount it directly before the enclosure. Some trv's utilize remote sensors which I would recommend. That way your radiator will react from the air temperature away from the baseboard. You just have to keep in mind trv's close and pipe accordingly. I don't think this should effect you much from the vague description you've given so far but there can be some considerations when you close off one loop of a zone.

 

[Al S]

Well you can mount it directly before the enclosure. Some trv's utilize remote sensors which I would recommend. That way your radiator will react from the air temperature away from the baseboard. You just have to keep in mind trv's close and pipe accordingly. I don't think this should effect you much from the vague description you've given so far but there can be some considerations when you close off one loop of a zone.

The "enclosure" I believe you're referring to is fin tube baseboard. You're suggesting mounting the TRV below it? I don't think there's clearance for that or do you mean in the basement? If true, that is totally impractical. Have to go to the basement to adjust the temp of one baseboard? Also, I thought I gave a pretty clear explanation of the beginning of this thread in the "Setup" What do you mean is vague? Additionally there is ONLY one zone in the monoflow system.

 

[John Gayewski]

Baseboard heating elements usually have enclosures. That's what anyone would mean by an enclosure.

If you are installing a baseboard you can choose where to put it, or how to orient the components. This is up to you to figure out. The enclosure should have different trim options. There are trim options that have doors that open to control valves. Normally people leave the valve trv exposed. Meaning you come up through the floor. 90 degree turn. Trv. Then enclosure.

If you use a remote sensor and put the valve inside of the enclosure it's a pretty simple and self explanatory thing.

Your vague description only includes the bare minimum of information and doesn't preclude putting the trv before the enclosure. I'm not really sure what your asking. Put it where you want. With fittings and pipe there's almost no limit to how you can intall things.

 

[Dana]

It's unlikely that you would need to swap out the tees to get the necessary flow into the baseboard convector unless the length of the baseboard is an order of magnitude (10x) longer than the width of the old recessed convector, with much longer pipes too/from the baseboard than previously.

Its likely that the runs of half-inch pipe & fittings to/from the convector create more head than the convector itself. If the runs to the 3/4" baseboard connections are 3/4" the head will likely be lower than the old runs of half-inch, and it's fine to use a 1/2" to 3/4" adaptor at the tee. Bumping up to 3/4" would likely reduce the overall pipe + convector head resistance, and the stubby section of 1/2" would handle the higher flow just fine. (If you're concerned about the flow now being too high and putting out too much heat you could install a flow balancer or a TRV, but that's likely to be overkill.)

The output of baseboard convectors changes very little between 1gpm & 4 gpm, so there is a lot of forgiveness factor in lowering the total head on that loop.

How long are the half-inch pipe runs to the old convector, with how many ells? How long (and with how many fittings) would he run to the newer-wider convector be?

Are the output specs for the baseboard roughly the same as the old convector, or is it higher/lower?