Outdoor Wood Furnace Info
All-Purpose OWF Discussions => Plumbing => Topic started by: markpallen on November 04, 2017, 08:40:24 PM
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I'm plumbing some old style radiators like the ones in some old schools. Slant front, made by Trane, 4 feet long.
Im needing to know how high off the floor they mount and if it matters which direction the water flows through it.
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It depends on if they get
their cool or intake air from the bottom of the housing or from low in the front, just be sure they can breath, no curtains over them or sofa covering them up, supply and return mean nothing on them and if they have no leaks and look presentable then you have just found a winning lottery ticket!
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Thanks slimjim ... lottery ticket eh... I like the sound of that.
These are never used but the metal looks bad from sitting in a warehouse for years. Nothing a little paint wont cover though. They get their air from the bottom.
I'm wondering if there is a magic distance from the floor for proper air flow?
Another question.... I'm running parallel lines off a main run using 3/4" copper. These two radiators I'm asking about will be back to back with one on either side of a wall. Is it bettwr to run a separate run off the main line or can I run one line and tee it to feed each radiator?
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I really don't know of any Magic number, I'm not quite that old but being a betting man as I am, I would bet that if you raised them the same distance that the outlet opening is then you would get lots of air flow. What size piping is on the inlet and outlet of the rad, if you match that with your parralel loop then I would think you would be fine with back to back.
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They are called connectors. If they don't have legs on them most engineers in the area I live want them 8" to the bottom. They them that high for the baseboard trim and so they can be cleaned easily under them. Piping doesn't matter. If you pipe them from below make sure they have a tap on the top of one of the headers to vent air out of them.
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Do these have the whole cabinet or just the base? Typically the ones I've seen in schools and hospitals with those coils are embedded within a cabinet, recessed into the wall and are called convectors. Usually in a stairwell or entryway. I had a whole school full of them this summer that were largely plugged after being converted from steam to hot water, and they were all 8" off the bottom of the cabinet which was recessed in the wall and had little fluting in the cabinet door for airflow. They were all piped in parallel and after a thorough flushing to remove the 80 year old gunk, put out a whole lot of heat. Hard to tell from your photo what's on top, but most have a 1/4" pipe plug on one side or another to be used as a vent. I've always been told that pipe plug is to be on the return side of the convector, so the supply water pushes the air to the vent.
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These rads have 3/4" inlets and outlets coming from the bottom of the unit. The exchanger itself is inside a metal cabinet and there are no provisions for air removal.
These will be surface mounted to the wall rather than recessed.
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That is a surface mounted convector. I have never installed a Trane brand but the Rittling and Vulcan ones we typically install you are able to flip the element in them to pipe them from the top.
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Are you able to drill and tap a hole in one end? I'm thinking you may possibly have an air issue unless there is a way down below to add a purge tee and force water through either with domestic pressure or a transfer pump. Purge tee w/ a boiler drain would also be dual purpose as a drain too, if that's something you wish to do. I'd do both if it were mine and were possible
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Let me start over....
Two level building.
on the main floor I will have a unit heater ceiling mounted. The radiators I'm asking about will be on the second floor and the piping is in the ceiling/ floor joist area between floors. That said, am I not better to pipe the rads from the bottom?
I'll post a crude sketch of what I'm thinking of doing in another post and maybe you can see what I mean as well as tell me what I'm missing.
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Clear as mud?
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Gotcha. Seeing as they're on the upper level, I would definitely recommend some sort of air removal device. If your boiler loop pump is big enough, you should be easily able to crack the valve or whatever you decide to put up there to bleed. That's how I always do them, but in previous discussions here, others mostly prefer to add valving to force domestic water through the system which also shoves the air back to the boiler. This also works well, but you also introduce new oxygenated water to your system and lose a bit of inhibitor from the overflow resulting from the new added domestic water. If your pump and piping can't support the head pressure to burp the air via a valve on top, the domestic purge is really the only option. All new installs I do, get a bleeder on the high point which allows any air trapped in the high point to be burped using the supply pressure from the boiler pump. This has always served me well, but I always size my pump accordingly too. Also, I do not recommend the bullhead tee you have drawn into the supply line under the convectors. Better would be to put the tee in the vertical and split it that way. It will take a couple extra 90s but will eliminate turbulence in the bullhead. With either setup, you'll want some sort of balancing valve on each unit to equalize flow between the two convectors. One ball valve on each supply or each return will accomplish this. Balancing valves are more ideal, but ball valves do work just fine
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I have no access to domestic water on the shop circuit so if make a high spot with a drain valve beside my second level radiators to let air out will this be sufficient? The water will be running thruthe rads continously with ball valves to determine water flow.
Am I correct in thinking I can crudely control the temperature by a) controlling flow rate to the upper floor rads.
b) control main floor temperature by hooking the fan on the air handler to a thermostat control?
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I have no access to domestic water on the shop circuit so if make a high spot with a drain valve beside my second level radiators to let air out will this be sufficient? The water will be running thruthe rads continously with ball valves to determine water flow.
Am I correct in thinking I can crudely control the temperature by a) controlling flow rate to the upper floor rads.
b) control main floor temperature by hooking the fan on the air handler to a thermostat control?
How would you intend to achieve this high point? A tee underneath with the branch aimed to a high point will not work, as the convector coil will still be above the tee. Perhaps I'm misunderstanding your thought, but a proper vent needs to be at the highest point that air can collect, in this case the top casing of the convector. Short of drilling and tapping the "manifold" portion of the coil on the end for a manual vent, the only other option I see is flipping the coil and piping it so the connections are on top and vent the high point there. You'd be able to crudely control temp with flow adjustment, yes. However the flow that works well at -30 is going to be sweltering on +30 days and vice versa. You'd almost need to adjust it every day the outdoor temp changes. I didn't realize this would be constant circulation earlier, but in this new light, thermostatic radiator valves would be the go-to or a zone valve to a thermostat if you wish. If the valve closes, the water would just short circuit through your unit heater instead of deadheading the pump. As for the unit heater control, a 120V line voltage thermostat wired right to the fan motor will control heat output while water constantly circulates through the coil
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I just took the radiator cover off and see that it is ported to vent from the top. So thats good. As far as heat extremes I will only be using the boiler in the fall and winter and even then sporatically. When I have more time I will look at hooking in the radiant floor too but for now I just need heat right away.Like by tomorrow. This is my best solution for the time frame I have.
Thanks to you guys for the help. :) :thumbup:
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I just took the radiator cover off and see that it is ported to vent from the top. So thats good. As far as heat extremes I will only be using the boiler in the fall and winter and even then sporatically. When I have more time I will look at hooking in the radiant floor too but for now I just need heat right away.Like by tomorrow. This is my best solution for the time frame I have.
Thanks to you guys for the help. :) :thumbup:
I thought so, as I'd never seen one without at least one tap on top. Glad you found them! When you tie in the radiant floor, please consider separating it from the boiler loop with a plate exchanger to make a closed loop and running it off its own pump. Hope everything works out well, good luck!
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If I do as you suggest that would allow me to run glycol in the slab , just in case....
Is that why you suggest this option over using a mixing valve?
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If I do as you suggest that would allow me to run glycol in the slab , just in case....
Is that why you suggest this option over using a mixing valve?
Multitude of reasons, but one of them is to add glycol, yes. You'll still need a mixing valve to temper water/glycol to the slab, as 160-180 or whatever temp your boiler water is is too high for a slab both for concrete longevity and efficiency. Too hot of water wastes fuel as well as heats the slab too fast which often overshoots the room temp excessively after the air temp reaches the setpoint but the floor is still 100+ degrees. This is also very uncomfortable on bare feet. Slabs should be mixed down to 100ish degrees ideally. Another reason I recommend exchangers is corrosion and sediment. Floors are often the low point in a system, and any sediment will settle to the bottom, eventually plugging the floor loops. This is why they recommend oxygen barrier PEX for slabs, because any oxidation (rust) from pump impellers or any ferrous piping, fittings, sediment in your domestic water, etc will do the same in an atmospheric system such as an outdoor boiler. Premixed glycol is inhibited, as well as diluted with deionized water which has absolutely no mineral or sediment in it to settle to the bottom. When converted to a closed system, the whole system is now completely isolated from oxygen and therefore cannot oxidize, allowing ferrous material if you want it. Fluid transfer is also much easier on the pump under pressure vs atmospheric.
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Ok thanks. That makes sense. Any chance you can sketch what it would plumb like with the exchanger and mix valve gping to the slab manifold. Or direct me to a schematic.
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Ok thanks. That makes sense. Any chance you can sketch what it would plumb like with the exchanger and mix valve gping to the slab manifold. Or direct me to a schematic.
I have a rough schematic in my phone that I drew for another forum-goer with the same issue recently, but I have absolutely no idea how to link a picture here. It tells me the file is too large. If you can maybe PM me your email, I can send it over that way?
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A pm has been sent. Many thanks.