I'm trying to help my father in law with a problem, and I'm not the most knowledgeable person on this subject, so I'd like to know if I'm not thinking through his problem correctly.
He has a 1950s(?) house with a modern propane heater to heat his hot water baseboard system.
They recently had the bathroom redone and they installed a new baseboard heater while they were in there. Now he doesn't have heat in the bathroom. Here's the layout of the system:
The red arrow indicates flow in the main hot water line in the basement ceiling. It then is just tapped off with a collar w/ a 1/2" (or 3/4?)" copper tube that goes up ~14" and over ~24" to poke up through the floor of the basement and into the heater.
I'm assuming that this is supposed to be full of water, and that the flow of the hot water through the main pipe is supposed to cause it to thermosiphon (helped along by a bit of venturi from the flow).
Now, my take on this is that there's no way to get air out of the system... So they're never going to get hot water in the pipes to do said thermosiphoning. I would have expected to have something like this (which appears to be called a "Baseboard Tee" fitting):
At the corner indicated by the green arrow in my picture so you can bleed air out of it. But they just put a 90° elbow there.
The guy who put it in has been back twice and there's still no heat, so I'm guessing that whatever his theory is isn't going to work...
Am I thinking wrong that I can solve this just by sweating the Baseboard Tee in and bleeding it?
Thanks!
Not a hydronic guru, but systems like this that use a single pipe require special "Monoflo diverter Ts" which create a restriction in flow in the main loop to encourage flow through the baseboard. So, if the wrong type of T was used in the main pipe, there will be no flow. A high mounted spot for air bleeding is also good.
Every radiator heat system I've seen has a bleeder, wether it's traditional or baseboard. 90% of the time a radiator is not putting off heat, bleeding it fixes it.
No Time
SuperDork
2/12/22 10:10 p.m.
I'm not a plumber, but based on my experience with baseboard heating systems, something looks off with that design. My high efficiency has a two loop system at the boiler, but both zones have serial flow ttrough all the heating elements in a zone, and no parallel/bypass circuits.
Bleeding is helpful, but when filling the system that uses continuous loops it is possible to flush most of the air out. Typically there will be an air scoop that will remove air bubbles from the water in the heating system over time.
If you are going to cut into that loop I would put a valve in the main loop between the tees going to the bathroom element. You can then use the valve to flush air out of the bypass, and also regulate flow that gets diverted through the bathroom element by closing down the valve until you get sufficient heat in the bathroom.
flat4_5spd said:
Not a hydronic guru, but systems like this that use a single pipe require special "Monoflo diverter Ts" which create a restriction in flow in the main loop to encourage flow through the baseboard. So, if the wrong type of T was used in the main pipe, there will be no flow. A high mounted spot for air bleeding is also good.
The one junction (the first one from the direction of the flow of the water) does have a adjustment valve on it, but the main pipe is ~2" and the one to the baseboard is only 1/2 or 3/4", so I can't imagine you'd want to put a restriction between the two legs to force water through that way. You'd be choking the flow down by something like 66% to divert only though that section.
Steve - That's the same with my limited experience.
No Time - Yeah, I've had a house with the "single circuit" style one, where the pipes went directly from radiator to radiator, but each of them had a bleeder on the upper floor... That's why I'm asking about this one :)
What's the worse case, you sweat the bleeder in and it's still broken? Worth a shot.
Steve_Jones said:
What's the worse case, you sweat the bleeder in and it's still broken? Worth a shot.
That was my take on it, but I won't have a chance to get back there until tomorrow, so I figured before I spend $25 (the cost of one of those stupid baseboard tees!), I'd ask on here :)
11GTCS
Dork
2/13/22 12:43 p.m.
flat4_5spd said:
Not a hydronic guru, but systems like this that use a single pipe require special "Monoflo diverter Ts" which create a restriction in flow in the main loop to encourage flow through the baseboard. So, if the wrong type of T was used in the main pipe, there will be no flow. A high mounted spot for air bleeding is also good.
This. If it's piped the way you show in the diagram there has to be something to create a pressure drop so that the flow of the water will go through the smaller branch piping to the baseboard radiation. That "something" is the monoflow tee which flat4_5 spd mentions. It has an scoop built into it that diverts flow in the piping main into the branch so water flows through the baseboard. These were a common thing in the 1940's and 50's when a single larger circulating pumps was typical. Newer houses are built with multiple piping zones with either zone valves or my preference, multiple zone pumps.
Edit for a link: https://www.homedepot.com/p/LEGEND-VALVE-3-4-in-x-1-2-in-Cast-Brass-Sweat-Copper-Monoflo-Scoop-Tee-3-4X1-2CST/202312920
Who installed it?
If it was a home improvement company have them come back and fix it.
And on that note, where I live just about anything that is done to a house needs to pass an inspection by the county.
Is that required where your parents are?
11GTCS said:
flat4_5spd said:
Not a hydronic guru, but systems like this that use a single pipe require special "Monoflo diverter Ts" which create a restriction in flow in the main loop to encourage flow through the baseboard. So, if the wrong type of T was used in the main pipe, there will be no flow. A high mounted spot for air bleeding is also good.
This. If it's piped the way you show in the diagram there has to be something to create a pressure drop so that the flow of the water will go through the smaller branch piping to the baseboard radiation. That "something" is the monoflow tee which flat4_5 spd mentions. It has an scoop built into it that diverts flow in the piping main into the branch so water flows through the baseboard. These were a common thing in the 1940's and 50's when a single larger circulating pumps was typical. Newer houses are built with multiple piping zones with either zone valves or my preference, multiple zone pumps.
Edit for a link: https://www.homedepot.com/p/LEGEND-VALVE-3-4-in-x-1-2-in-Cast-Brass-Sweat-Copper-Monoflo-Scoop-Tee-3-4X1-2CST/202312920
It has an adjustable version of that on the main line, but either it's broken or it doesn't seem to be enough to force the air out of the high spot?
Noddaz said:
Who installed it?
If it was a home improvement company have them come back and fix it.
And on that note, where I live just about anything that is done to a house needs to pass an inspection by the county.
Is that required where your parents are?
No idea... They're in Mass. It was a sub contractor for the guy who was redoing the bathroom. I don't know whether it was a company or a "guy he knew." And yes, I agree, but he's been back two or three times and hasn't fixed it yet, and as much as I'd love to hold him accountable, I don't want my in-laws to have to go all winter without heat in the bathroom...
This looks all wrong compared to the system in my house. Original 1958 boiler system. I have one main log coming off the boiler 1 1/2 pipe with three or four circuits looped off of the main output high side each with its own flow valve to balance each zone. The circuits all return to a main line. I may be backwards on the flow as it makes more sense to me to restrict the return.
Mom and Dad's house and my bestie's house both have baseboard hot water. Both of them don't use any thermosiphoning like your picture shows. There is a pump from the hot water tank manifolded out to all the baseboards, and they're all manifolded back to the furnace. All of them are positive flow things, not passive/venturi/conduction.
I could see adding a supplemental system with proper diverters to cause a pressure variant and therefore flow, but yes... you would need a bleeder at the highest point.
