Need some help with baseboard hot water and PEX


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Old 09-20-11, 07:29 AM
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Need some help with baseboard hot water and PEX

Hi guys, here's a little background on what I'm trying to do. I'm finishing my basement and want to add hot water baseboard radiators to my existing boiler. I asked a few questions here a few months back and we determined that my boiler has the capacity figured out my heat loss and all that good stuff. I decided on two kickspace heaters for the movie room and game area (one big room) and a 4' baseboard for the bedroom and 3' baseboard for the laundry room. Here's a floor plan of that:


(top view)

The bathroom will eventually have electric radiant heating beneath tile, the storage room can be cool, and the workroom is heated enough by the boiler running in there.

I'm going to run barrier PEX between the heaters and it will be mostly run in the ceiling. From the boiler it will go up into the floor joists all the way to the bedroom heater. The two kickspace heaters will connect to that run with tees (see picture a little ways down, the maker of the kickspace heaters recommends they be teed off the main line). From the bedroom to the laundry room I'll run PEX through the studs of the exterior wall (there's R10 spray foam and I'm in MN, is this ok?) and then from the laundry room back to the boiler it will be in the ceiling again.

First off, is this seem like a good way to run everything?

If so, I'm trying to figure out exactly where to put drains and vents. I figure I can put a vent in the work room on the send and return and that will cover the two high points. The drain on the boiler should also cover draining from the laundry room to the boiler and from the bedroom to the boiler (except the two kickspace heaters). I'll need a drain at both kickspace heaters and somewhere in the low point between the bedroom and laundry room - I'm thinking on the send side of the laundry room baseboard since there's a floor drain in the laundry room.

Is that OK so far?

I've been having a hard time finding PEX fittings for vents and drains but here's what I've come up with so far for the two kickspace heaters:


(side view)

The ball valve (with drain) fittings will be something like this and the drains something like this.

Ball valve1 can be partially closed to send more flow to the kickspace or left open and ball valve2 or 3 can be partially closed to send less flow to the kickspace. Also, ball valve 2 and 3 can be closed completely to drain the heater for service. If I put the "drain" on the heater side of the fitting I figure I can open it as a vent when the valves are closed in order to drain the heater or open the valves and close the "drains" on the valves if I need to drain the entire system.

This post is getting really long but hopefully you bared with me and have some advice for a guy who's pretty green when it comes to plumbing

Thanks in advance,
Mike
 

Last edited by HomeAlterations; 09-20-11 at 09:52 AM.
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Old 09-20-11, 03:22 PM
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Mike, not much time right at the moment, but wanted to ask if you were aware that those 'tees' going to the kickers need to be 'venturi' tees?
 
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Old 09-20-11, 03:41 PM
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Bedrooms normally need to have two means of egress, for safety. Check that out. Sometimes, you can install a special basement window to serve that purpose.

It looks like the whole basement is on one series loop. Is that correct? The tail end may be a little cool? What size Pex are you planning to use? When you said the kickspace heater mfg suggest it be teed off the main, normally they are talking about monoflo tees. Your way may be OK, but the size of the tubing to, from, and through the kickers should be the same size as the main - otherwise, when you throttle Valve #1, it'll starve flow to the rest of the loop. (Likewise, the size of the tubing through the fin-tube units should be the same as the main.)

For the main, I'm just horsebacking maybe a 1" line - which means all the series heat emitters need to be 1", too. The alternative would be a 1" main with 1"x3/4"monoflo tees and supply/return legs.

My first impression was that the heat emitters might be a little skimpy - but basements lose much less heat, of course. Have you tried to estimate the heat loss in the basement? It's a little tricky - I've used the exposed foundation as an exterior wall, plus maybe two feet for the below-ground portion - and, of course, the rooms above will be heated.

The three drain valves for the kickspace heaters seems like overkill. What's their purpose? If it's just to purge the air out of the kickers, ball valve #1, plus either ball valve #2 or #3, and the other drain valve should allow a power flush to remove trapped air in the kickers. I don't see a need for drains with Valves #1 or #2.

You will need a zone valve controlled by the thermostat for the basement loop. An alternative would be to add a manual balancing valve in the series basement loop.

I'm always leery of running pipes in outside walls due to freezing potential. Perhaps others will opine.
 
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Old 09-20-11, 04:34 PM
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I'm going to do something similar in my basement. The difference is that I will be using cast iron rads and it will be a workshop. But the similarity will be having the supply line running at the ceiling and dropping down for each radiator. I do plan to put drains at each radiator so I can drain all the water out of that zone whenever I need to. I have a similar issue with my 2nd floor zone. It's a series loop that goes up to the 2nd floor and back down to the basement for each radiator. It doesn't drain all the way and takes forever to get the water out that does come out. I don't think you need any vents on the zone. The setup you have going at the kick space heaters will allow you to purge air from them. Add a purge station at your boiler and that will allow you to get most of the air out of the zone when you fill it. The vent at the boiler should handle the rest.
 
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Old 09-20-11, 05:31 PM
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Some suggestions

1) make sure this loop (and the system in general) is pumping away from the expansion tank. That will help immensely in keeping positive pressure through the system, and air bubbles compressed until they reach the elimination point. You have a lot of ups and downs.

2) don't run piping in outside walls.

3) kickspace heaters are noisy. If you watch quiet movies, use something else.

4) you might consider a home-run type piping system to each room. That would keep the supply temperature more even and make maintenance simpler. Would also simplify piping and avoid outside walls.
 
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Old 09-21-11, 07:08 AM
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Originally Posted by NJ Trooper View Post
Mike, not much time right at the moment, but wanted to ask if you were aware that those 'tees' going to the kickers need to be 'venturi' tees?
Mike, One of my frustrations with PEX so far has been the lack of fittings. I haven't seen a venturi /monoflo tees for PEX. The kickspace heater install guide said to put a valve between the two tees if you can't use monoflow in order to partially divert more flow to the kickspace. Have you seen venturi tees for PEX?
 
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Old 09-21-11, 07:37 AM
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Originally Posted by gilmorrie View Post
Bedrooms normally need to have two means of egress, for safety. Check that out. Sometimes, you can install a special basement window to serve that purpose.
Yep, there's already an egress window.


It looks like the whole basement is on one series loop. Is that correct? The tail end may be a little cool? What size Pex are you planning to use?
The plan was to put it on a series loop with 3/4" PEX. I did a few heat loss calculations - some estimates and one where I broke down and did all the math. Surprisingly it's only about 6k-8k BTU/hr. According to the manufactures, the two kickspace heaters give off 3k BTU/hr each (on the low setting), the 4ft bedroom slantfin multi/pak 80 will give 2800 BTU/hr, and the 3ft laundry will give 2100 BTU/hr, assuming 170 degrees which my boiler typically runs. Maybe I should recalculate with something like a 10 degree lower water temp after each heater? I'm not too worried about the laundry room temp and it's last on the line.

When you said the kickspace heater mfg suggest it be teed off the main, normally they are talking about monoflo tees. Your way may be OK, but the size of the tubing to, from, and through the kickers should be the same size as the main - otherwise, when you throttle Valve #1, it'll starve flow to the rest of the loop. (Likewise, the size of the tubing through the fin-tube units should be the same as the main.) For the main, I'm just horsebacking maybe a 1" line - which means all the series heat emitters need to be 1", too. The alternative would be a 1" main with 1"x3/4"monoflo tees and supply/return legs.
I replied to Mike about the monoflo tees too, I can't find them for PEX so partially closing the main line between the two tees is my alternative but I'm all ears for better options. The plan is to use 3/4" PEX for everything. The baseboard heaters have 3/4" copper through them so that's no problem but the kickspace heaters have 1/2" connections. Maybe I'm making a bad assumption but I figured the tees would send a 1/2" worth of flow to the kickspace and the extra would continue on in the main and not reduce flow to the system. Will that work?


My first impression was that the heat emitters might be a little skimpy - but basements lose much less heat, of course. Have you tried to estimate the heat loss in the basement? It's a little tricky - I've used the exposed foundation as an exterior wall, plus maybe two feet for the below-ground portion - and, of course, the rooms above will be heated.
I hit on this above. If you're curious, here's the original thread where the DIY forum guys helped me figure out the heat loss.

The three drain valves for the kickspace heaters seems like overkill. What's their purpose? If it's just to purge the air out of the kickers, ball valve #1, plus either ball valve #2 or #3, and the other drain valve should allow a power flush to remove trapped air in the kickers. I don't see a need for drains with Valves #1 or #2.
My thought for having drains on #2 and #3 was just for draining the water out of the kickspace heater if I or someone in the future needs to replace it or work on it. I figured if I open the drain and don't have any valves on the send/return line I'd essentially be draining the whole line. In order to just drain the one heater I want to put a valve on the send and return but without any vents on them the drain won't do anything because of the suction in the pipes so I thought I'd put ball valves with "drains" on #2 and #3 so the drains would act as vents just for draining the heater. I wouldn't use the "drains" on #2 or #3 to remove air or drain water, just for helping the drain. Does that make sense?

You will need a zone valve controlled by the thermostat for the basement loop. An alternative would be to add a manual balancing valve in the series basement loop.
Already done I added two zone valves, one to for the main level radiators and one for the basement loop. One thermostat on each floor wired to the zone and boiler.

I'm always leery of running pipes in outside walls due to freezing potential. Perhaps others will opine.
I'm hoping to hear more on this too. PEX can take a freeze but obviously ice in the line won't be good for the flow. Will a line in the wall really freeze when the exterior wall is insulated and the room is 60+ degrees on the other side of the drywall?

Thanks for the reply and questions. I want to do this right and I like hearing from people with more experience than me!
 

Last edited by NJT; 09-22-11 at 03:06 PM.
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Old 09-21-11, 07:40 AM
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Originally Posted by drooplug View Post
I'm going to do something similar in my basement. The difference is that I will be using cast iron rads and it will be a workshop. But the similarity will be having the supply line running at the ceiling and dropping down for each radiator. I do plan to put drains at each radiator so I can drain all the water out of that zone whenever I need to. I have a similar issue with my 2nd floor zone. It's a series loop that goes up to the 2nd floor and back down to the basement for each radiator. It doesn't drain all the way and takes forever to get the water out that does come out. I don't think you need any vents on the zone. The setup you have going at the kick space heaters will allow you to purge air from them. Add a purge station at your boiler and that will allow you to get most of the air out of the zone when you fill it. The vent at the boiler should handle the rest.
I'm jealous you're using cast iron! In MN salvaged rads sell for about $30/fin and that gets expensive fast!
 
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Old 09-21-11, 07:53 AM
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Originally Posted by xiphias View Post
1) make sure this loop (and the system in general) is pumping away from the expansion tank. That will help immensely in keeping positive pressure through the system, and air bubbles compressed until they reach the elimination point. You have a lot of ups and downs.
The pump is at the end of the return sucking water through the line. I'm not entirely sure where the expansion tank fits into the system. It looks like the pipe to the tank just goes into the boiler and from there I'm not sure what it does.

2) don't run piping in outside walls.
Does that mean I shouldn't have the baseboard heaters on outside walls at all? I wouldn't be able to connect them if they are.

3) kickspace heaters are noisy. If you watch quiet movies, use something else.
Hmm, I'll have to consider that. I was planning on leaving the fan on low and the heater will technically be in the storage room with a vent into the movie room. I wonder if I can find a spec on the db level of the fans?!

4) you might consider a home-run type piping system to each room. That would keep the supply temperature more even and make maintenance simpler. Would also simplify piping and avoid outside walls.
I had considered this but ended up moving away from it because it would take over 2x the pipe. That's a good point that it would make the supply temp more even but unless I move the baseboard heaters to interior walls I would still have to make runs on the exterior...
 

Last edited by NJT; 09-22-11 at 03:09 PM.
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Old 09-21-11, 02:52 PM
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Keep in mind this is a basement. So an outside wall here should be at least partially below grade. How much of your foundation is above grade? If you can't avoid putting the pipes in an outside wall, try spray foaming that bay. You will get double the r-value per inch. I would leave the side of the pipe facing the inside of the room clean of insulation. I have two radiator pipes running in an outside wall. There is some fiberglass batt stuffed between the pipe and the sheathing. On the interior side of the pipe is 3/4" pine that is being used as a side to built in shelves. I can say I have no trouble with that setup, but I certainly aren't crazy about it.

I moved one of the radiators out of my living room into the basement. I want to add 2 or 3 more. I have yet to get my hands on them. Check out craigslist. I see postings all the time for cast iron rads for good prices. Condition could be an issue with some of these, but a lot of them are people just trying to get someone to haul them away. I also have a connection that has them come his way every now and again. He says I'm next on his list. I don't know if there will be a price attached to them or not. We'll see.
 
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Old 09-21-11, 03:10 PM
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Dear Drooplug & HomeAlterations: I have basement radiators, fed from above. I don't have any way to drain them, at least conveniently - but I've never seen the need. Under what circumstances would you need to drain them?
 
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Old 09-21-11, 04:42 PM
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For the same reason you would drain 1st floor and second floor zones. To perform so kind of maintenance on the loop. No way to predict what will need to be down in the rest of the years of my life. There could be a leak somewhere. Maybe I need to move the radiator to perform some other task in my basement. Sure, you could drain as much water out of the zone at the boiler that you could. Then crack open a union at the radiator and catch all the water with a dozen towels, but that's a mess. I prefer to work smarter, not harder.
 
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Old 09-22-11, 06:55 AM
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Originally Posted by gilmorrie View Post
Dear Drooplug & HomeAlterations: I have basement radiators, fed from above. I don't have any way to drain them, at least conveniently - but I've never seen the need. Under what circumstances would you need to drain them?
I've lived in my house for 18 months and I've already drained my boiler twice - first so I could disconnect the radiators and move them while I refinished hardwood floors, second so I could re-rout some of the boiler pipes and disconnect a radiator to paint it. I don't anticipate having to drain it again for a good long time but if one of my baseboard radiators has a problem I want to be able to take the water out before I disconnect it or I'll have a couple gallons of water coming out of the pipe.
 
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Old 09-22-11, 03:21 PM
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Mike, One of my frustrations with PEX so far has been the lack of fittings. I haven't seen a venturi /monoflo tees for PEX. The kickspace heater install guide said to put a valve between the two tees if you can't use monoflow in order to partially divert more flow to the kickspace. Have you seen venturi tees for PEX?
You're Mike! I'm not!

I did google around a bit looking for venturi for pex, and did happen upon these:

PEX Tubing Mono-Flow Tees. PEX Monoflow Tees. Mono Flo Tees for 1/2 " and 3/4 " PEX Pipe

It appears that this is simply a standard monoflo with a pex adapter pre-soldered into the run of the tee. The bull of the tee is still just a copper fitting...

I don't think the idea of using a valve between is necessarily a bad idea. It will serve the same purpose as the monoflos, creating a pressure drop between the tees, and it will work. The trick is going to be getting the valve adjusted just right, so plan on some experimentation with that. Ball valves aren't the best for 'throttling' applications, very 'touchy' to get them adjusted just so. If you chose to go this route I would consider using a good quality globe valve in that application. (not one of those el-cheapo chinese 'stop' valves from the big box store! Get a GOOD one!) The globe valve will be MUCH easier to adjust the flow to the heater. Start with it full open and close it only enough to get enough hot water to the kicker. Ya know, you might even find that by using a globe valve in that application that you will have enough pressure drop to flow the kicker... you might not have to close it at all...

Something like this perhaps:

Patriot Supply - 103-104
 
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Old 09-22-11, 03:38 PM
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I'll run PEX through the studs of the exterior wall (there's R10 spray foam and I'm in MN, is this ok?)
I suspect that some of the guys may have missed this in your first post...

I should think that you would be fine as long as the tubing was on the warm side!
 
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Old 09-23-11, 03:43 PM
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Haha, sorry! I think there's another Mike from NJ around the forums...

I hadn't though of it but I really could make my own PEX monoflow tees by just soldering PEX adapters onto copper fittings, that way I don't have to make an access panel for the valve on the main line. I already have to solder PEX adaptors for all the heaters, what's a few more? This project is failing the "PEX is easier" ideology.

As for the exterior wall, I could also run the pipe between two gas lines that hand below the joists and travel between the bedroom and laundry but something about heating up gas lines makes me nervous. I could also drill holes in the joists and go into the ceiling again but either way adds more ups and downs and I'd need more vents and drains. I really don't see these pipes freezing on the warm side of the insulation.
 
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Old 09-23-11, 05:16 PM
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Haha, sorry! I think there's another Mike from NJ around the forums...
Yup, but he's much smarter and much better looking than me!

Let's change the adage:

"PEX is SOMETIMES easier!"

All those brass adapters get pricey after a while. I kinda like the idea of the cheap tees and the not so cheap globe valve myself. With a valve between the tees, you also have the option of closing that completely for purging, as you have noted earlier. You'll probably still need a few adapters though!
 
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Old 09-26-11, 06:39 PM
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Question Adding a few bb heaters to pex heating system

I am in the process of finishing my basement and have run 3/4 pex along an exterior (under ground level) wall. I am about to add insulation, drywall, etc though I am little confused with the connections between the pex and the baseboard and when in the process the connections should be made. I t'd off the existing pex hot water lines and added an 8 foot gap where i will be installing the heater.

1) can sharbite connections be used to connect to the baseboard heater?
2) how much distance should i leave in the 8 foot gap in th pex line where I will be placing a baseboard (8 feet I assume). The start of the baseboard will be partway between a 2x4.
3) what's the best way to install the drywall over the tips of pex that will be connecting to the baseboard heat after the drywall and the molding go up. Distance from floor? Copper elbows?
 
 

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