? on radiant heat ...

[patch53]

I have one radiant zone in my house that runs to our sunroom. Whe had it put in about 3 years ago and the guy who installed it put a Taco 009 on it. I asked him today why such a big pump was needed and he said because radiant in-floor heat requires a much bigger pump because of the smaller pex and the amount of piping. The total length of the run, including what in the concrete, is about 250 feet. There is no vertical head. Does this sound right or is this way more pump than I need?

TIA, Pat

 

[WoodNotOil]

A lot of installs I see (mine included) were designed with the Grundfos 3-speed pump. My supplier sold me an Azel digital temp monitor with two sensors. I was instructed to put one on supply, the other on return and adjust the pump speed until I got a good differential.

I would think a 007 would likely be fine, but then again I don't know all the details of the setup. Is the pipe 1/2"? That sounds like a fairly short run...

 

[webie]

Patch 53 I too have one radiant run in my house to my sun room . It was installed about in 2000, ( Reason for SOLO60 in 2001 ) . Anyways Sun room is 640sgft and is running 4- 250' loops of 1/2 pex and about another 40 ft of 3/4 copper to feed these back and forth . The guy whom installed mine put in a taco 007 I never questioned it , it seems to work fine .

 

[DaveBP]

If it is one single loop of 250ft. length, 3/8" PEX would have 4 times more resistance to flow than 1/2" with an 009 on it. What size tubing is it?
If he used the smaller tube the larger pump may be necessary.

 

[patch53]

Thanks for the replies gents. It is 1/2" ID pex. Outside diameter looks to be about 3/4".

 

[tom in maine]

This is one loop? Or is it a couple in parallel?

 

[patch53]

This is one loop? Or is it a couple in parallel?

Just one loop Tom. Personally, I think the Taco 009 is way more than I need. When the pump kicks on it only takes about a minute for warm water to retun to the pump.

Pat

 

[DaveBP]

Patch, if you don't have a use somewhere else for the pump you have in there now you'll be spending 75 dollars or so to pump water through there more slowly. It will use less electricity while it does it but it will run more to do the same heat exchange as the bigger pump. I don't know what the resulting difference in your electric bill will be but it might make the payback on the smaller pump a very long term proposition.

One other aspect of pumping slower is that the return water might be cooler on average. If you have a condensing boiler on it that will make it run more efficiently. It can be a disadvantage in some other situations depending on your system.

I'm a fan of smaller circulators but once a circulator that's a little bigger than necessary is installed and paid for sometimes I think it's best to just wait for it to run out its service life and then replace it when you'd be spending the money anyway.

Unless it just really pisses you off.

 

[patch53]

Hi Dave. Currently I am running 3 zones. 2 basebaord and the one radiant. They all have separate pumps. the baseboards have Taco 007's.

I am changing all my plumbing next spring. Putting in storage. I recently purchased a Grundfos Alpha to replace all the pumps and go with zone valves. I also want to add a hot water maker like an Amtrol Boilermate or something similar. So with the new system I would have 4 zones. I'm sure I could run the 2 baseboards and the HW maker off the Alpha, but not sure it will work with the radiant added in. If I can get by with a Taco 007 on the radiant, I could live with that. I wouldn't have to buy a new 007, just use one of 2 I have now. I also have back-up Taco 00R, 3-speed, that I could use. that way if the 007 isn't strong enough I could put that in and it would probably be fine.

Pat

 

[tom in maine]

This is about 4 feet of head at 2 gpm.
A 007 can handle this.

 

[patch53]

This is about 4 feet of head at 2 gpm.
A 007 can handle this.

Thanks Tom, I think so too. Ideally I would like to be able to run all 4 zones off the Alpha, but I probably should just isolate the radiant w/ the 007. I can always change it to a bigger pump if I have to.

Pat

 

[DaveBP]

If you have the circulators and you're pulling it all apart anyway, I'd definitely put in a smaller circ on the radiant loop.

Are you feeding the radiant slab with baseboard temp water? Near 180F?. That's pretty hot water to send into concrete. Or does the radiant slab get the water after one of the baseboard circuits and therefore get lower temp water?

 

[Fred61]

I would check the supply return differential. If you're planning on installing storage, water returning that is nearly as hot as supply, really screws up your tank stratification.

 

[patch53]

If you have the circulators and you're pulling it all apart anyway, I'd definitely put in a smaller circ on the radiant loop.

Are you feeding the radiant slab with baseboard temp water? Near 180F?. That's pretty hot water to send into concrete. Or does the radiant slab get the water after one of the baseboard circuits and therefore get lower temp water?

The radiant zone has a mixing valve that I set at about 140F max. The way the plumber set this up was that the return water from the radiant is mixed with supply water (160-180F) .

 

[patch53]

I would check the supply return differential. If you're planning on installing storage, water returning that is nearly as hot as supply, really screws up your tank stratification.

Yeah I was thinking about that last night. If I'm going to be adding a storage tank, and I need a seperate circulator for the radiant zone, would it be a good idea to just plumb the supply to the radiant zone from the bottom of the storage tank? That way the radiant zone would only be using cooler water. Now I know that just after charging the tank I would have 185-190F water all the way to the bottom of the tank, so I would still need the mixing valve, but for most of the time the radiant zone would be using the cooler water at the bottom of the tank and not the "good" hot water at the top of the tank.

I am only going to running my storage tank down to about 150F before refiring and recharging. Anyone see a problem with this scenario ?

thx, Pat

 

[webie]

Yes I see a problem with using the cooler water from the bottom of the tank . Where are you going to return the even cooler water back to the bottom of the tank ? And if you do that I think that will require 2 pumps a charge pump and then your radiant loop pump ( Wait a minute what if you circulated the water in the radiant floor only If there was a call for heat from one of your other 2 zones , there by reuseing the return water from your baseboard use what ever heat available left to mix for your radiant loop and then back to the bottom of your storage tank) . The only other thing I was thinking about that why he used a bigger pump may be the fact that as in my sunroom I have to heat that floor pretty good in order to get some heat for the room I was wondering if he did it just to keep the entire slab the same temp to eliminate any cold spots by circulating the water fast . I can tell you this if you really wanted to change out that 009 radiant loop pump and you have that 00R pump extra I would use that as it would give you the different speed options .
My return temp is to hot from when my radiant calls for heat and my zone circ runs to provide the little bit of mixing water , This is what I am hoping to help by installing my alpha pump as my zone circulator pump , (The grundfos alpha should be arriving today )
It sounds like your house and heating is similar to mine , as I run basically 2 zones with baseboard another zone with a pair of 15,000 BTU water to air wall heaters in the sunroom and then the radiant mixed loop for the sunroom floor So a total of 4 zones.
I would when you redo your system use the Taco 00R 3 speed that would be my vote if you are not happy ( pissed off at the 009 ). I would actually like to know if you notice any difference the way the floor is heated by useing the different speeds . It could all be that at the end of the 250 ft run your charge may be out of heat and your floor will be heated unevenly
How warm do you actually heat your floor up to , I heat mine up now between 90 and 100 actual temp acording to the tekmar . I just got an infared thermometer and when I was walking around checking actual surface temps I was anywhere from 77 to 87 and this was when the tekmar was set at maintaining 95 . My return temp comeing back to the mixer is what my floor temp is . My mix temp in is 120 -125

 

[patch53]

Yes I see a problem with using the cooler water from the bottom of the tank . Where are you going to return the even cooler water back to the bottom of the tank ? And if you do that I think that will require 2 pumps a charge pump and then your radiant loop pump ( Wait a minute what if you circulated the water in the radiant floor only If there was a call for heat from one of your other 2 zones , there by reuseing the return water from your baseboard use what ever heat available left to mix for your radiant loop and then back to the bottom of your storage tank) . The only other thing I was thinking about that why he used a bigger pump may be the fact that as in my sunroom I have to heat that floor pretty good in order to get some heat for the room I was wondering if he did it just to keep the entire slab the same temp to eliminate any cold spots by circulating the water fast . I can tell you this if you really wanted to change out that 009 radiant loop pump and you have that 00R pump extra I would use that as it would give you the different speed options .
My return temp is to hot from when my radiant calls for heat and my zone circ runs to provide the little bit of mixing water , This is what I am hoping to help by installing my alpha pump as my zone circulator pump , (The grundfos alpha should be arriving today )
It sounds like your house and heating is similar to mine , as I run basically 2 zones with baseboard another zone with a pair of 15,000 BTU water to air wall heaters in the sunroom and then the radiant mixed loop for the sunroom floor So a total of 4 zones.
I would when you redo your system use the Taco 00R 3 speed that would be my vote if you are not happy ( pissed off at the 009 ). I would actually like to know if you notice any difference the way the floor is heated by useing the different speeds . It could all be that at the end of the 250 ft run your charge may be out of heat and your floor will be heated unevenly
How warm do you actually heat your floor up to , I heat mine up now between 90 and 100 actual temp acording to the tekmar . I just got an infared thermometer and when I was walking around checking actual surface temps I was anywhere from 77 to 87 and this was when the tekmar was set at maintaining 95 . My return temp comeing back to the mixer is what my floor temp is . My mix temp in is 120 -125

Hi Webie, well if am sending 140F water into the radiant zone and its coming back at say 120F, that water would be coming back into the same return line as my baseboard zones and then into the bottom of the storage tank. That water gets mixed a bit as it enters the tank and then drawn back out into the boiler loop. I guess I don't see that as a problem?

My sunroom is virtually impossible to keep warm when its 0F like it is today. Even with the floor toasty warm, the best I could do would be about 50F on a cold day. We have a hot tub in there that we use only in fall thru spring, not in summer. I have never actually checked the floor temp, but I would have to say at least 90F, its quite warm to the touch after its been on for several hours. We just don't use the sunroom when it gets really cold out. During the day when temps get up around 20F outside and we get a little sun it gets nice in there. But a lot of days in the winter its just too cold to use it, we don't mind. I actually like going in the spa at night when its cool in the sunroom.

Not sure what the plumber was thinking when he put the 009 on it. When I talked with him yesterday, I got the feeling that he put that size pump on because he thought it was needed because of head, not heat output.

I can always plumb this with shutoff flanges so that if the 007 doesn't work I can easily move up to a bigger pump without a problem. My goal here is to just have a system that will provide enough heat to the sunroom to keep it warm enough to use on some winter days. It gets too cold here to even think about using it every day in the winter. We knew that ahead of time and have no problem with that. We like to use it mostly in spring and fall when its always toasty in there, and on those nice sunny winter days.

Thx, Pat

 

[webie]

You must have had the same builder for your sunroom as I did . I always claim its like heating a corn crib ! I only heat it on the weekends, during the week I have it set up so it stays at 33 . In fact right now the floor is running and its temp is a balmy 40 degrees . I myself call it off when its 0 or below its almost futile to try and heat it and thats with the floor cranked up the wall heaters going and I have a pellet stove in there too . I too have a hot tub out there ( this summers heating project )
Always use shut off valves when plumbing pumps, never know when you will puke a pump or have a wild hair and just want to change it .
Oh by the way I had zero to this morning .

 

[patch53]

You must have had the same builder for your sunroom as I did . I always claim its like heating a corn crib ! I only heat it on the weekends, during the week I have it set up so it stays at 33 . In fact right now the floor is running and its temp is a balmy 40 degrees . I myself call it off when its 0 or below its almost futile to try and heat it and thats with the floor cranked up the wall heaters going and I have a pellet stove in there too . I too have a hot tub out there ( this summers heating project )
Always use shut off valves when plumbing pumps, never know when you will puke a pump or have a wild hair and just want to change it .
Oh by the way I had zero to this morning .

LOL, yeah sounds like you have a very similar set-up. What I ususally do is to take one day a week and turn up the sunroom thermostat and let it run all day. I got some old relatively dry white birch that i throw in the boiler. I can get the floor really warm and it will stay that way for several days, then I just shut it off for the rest of the time. But on days like today and last night ( I had -6F this morning) even with the thermostat down all the way it gets cold enough to turn on the pump. I love our sunroom, but they are a b#tch to heat !

Pat

 

[webie]

Well you know what our weather has been like this week My slab was 95 on Sunday night . Thats when I set it back to its weekly temp of 40 . It maintained the temp till last night , in fact the radiant floor just kicked in . I too love my room , reminds me of when I lived at home single pane glass 3/4 inch of ice on it ,curtains moveing in the breeze , Mom giveing me my 4th quilt to cover up with . ( Oh wait I paid 31000 for glass for a sunroom the windows are perfectly clear not even a hint of moisture ( the aluminum between the windows has a 1/2 of ice on ) only breeze I get is from the blower on the pellet stove. Got to love it
Webie

 

[patch53]

LOL, yeah I remember those days too. How big is your sunroom? Mine is about 24' X 15'. I bought mine in a kit from Global Solarium out of Vancouver, WA, they custom make them any size you want. It was WAY cheaper than anything I could find around here.

Pat

 

[webie]

My sunroom is 22'X 30' and actually came from 4 seasons sunrooms out of Appelton Wi I am not sure where the head quarters are. Ifg I can figure out how to resize and post a picture I will .

 

[heaterman]

007 or even smaller. That's a tiny load and the 009 is probably running waaaay past it's optimum curve. Yank it and put it on E-bay or Craigslist. It's also about twice the cost of a 007 or 15-58.

 

[patch53]

Thats a good sized sunroom, I can see why its hard to heat. We checked with 4 Seasons out of Marquette first, they wanted $45K to put ours up ! We got the kit and my neighbor who is a contractor helped me put ours up for 1/2 of that amount. 4 seasons makes a quality sunroom, but very expensive.

Pat

 

[webie]

not sure what I am doing but here goes