Questions about radiant heat system

[mx842]

Exactly.

I have been checking the floor temp for a couple days now and the floor temp has risen to mostly 69 degrees all over, up from an average of 55 before. There are a couple cooler spots in places that I planned on not getting as warm like in my welding room and my parts room. The temps in those rooms are around 65 all over. They are both small rooms (10X10) in size that I didn't need to be real warm. The days have been mostly warm mid 50's in the day time and 30's to low 40's at nights with a couple nights in the 20's but it warmed up pretty fast come morning.

Where as there feels like a big difference between the water going into the floor and the water coming out the temp gauges are showing about 20 to 30 degrees difference between the two sets of manifolds. It's hard to see those little gauges with my poor old eyes but I think that's about right. I haven't been making really hot burns just keeping enough wood in there to keep the tank water around 140 degrees because I didn't want to load it heavy until I was sure both my pumps and controls were working and all my leaks were gone which at this point seems like all is good.

Also I have noticed that the stove doesn't seem to be making anywhere near the creosote it was before. I've only cleaned the stove pipe one time since I fired it off and there was just a small bit of paper like stuff in the section that connects to the schedule 40 stove pipe that goes through the wall. I have a section of lighter gauge stove pipe that connects to the schedule 40 and turns up about 10 feet. I need to extend this at least another 10 feet to get it above the main roof line of the building but didn't want to mess with that until I got everything else all straightened out. I've been looking for a schedule 40, 4 way slip fit connector to make up the whole stove pipe and chimney system. That way I can add 20 ft of pipe to get over the ridge line and have a port hole to rake the stove pipe and to rod the chimney pipe and have another section below the 4 way with a clean out door sitting on a concrete pier to hold the weight of the whole structure. I'll probably have a couple guy wires attached to the corners of the building to help support it also just to be safe. That pipe is pretty heavy and I wouldn't want it to fall over on some thing or some one that happens by.

 

[Raspy]

mx,

It's nice to be in the fine tuning stage after a difficult installation.

The best points of you're report are: Low fire produces enough to make a significant change in the entire floor. Chimney is staying clean. Getting flow to all loops and the floor is coming up evenly. The whole system is settling in with no drama.

Excellent. You may find that a higher head pump will bring the supply and return temps closer, which will even out the floor temps, but that can come later if needed. It sounds like your HX and tank side of the equation is doing fine too.

I hope you have a relief valve on the system and have some kind of way to get it under control if there is a power failure. Thermosyphon will help.

Good job. Let us know how it's doing

 

[mx842]

mx,

It's nice to be in the fine tuning stage after a difficult installation.

The best points of you're report are: Low fire produces enough to make a significant change in the entire floor. Chimney is staying clean. Getting flow to all loops and the floor is coming up evenly. The whole system is settling in with no drama.

Excellent. You may find that a higher head pump will bring the supply and return temps closer, which will even out the floor temps, but that can come later if needed. It sounds like your HX and tank side of the equation is doing fine too.

I hope you have a relief valve on the system and have some kind of way to get it under control if there is a power failure. Thermosyphon will help.

Good job. Let us know how it's doing

Yeah I been looking at that Grunfos 26-99 3 speed you were talking about and maybe in a couple weeks i can get one of those. I still have some air in the system that just wont work it's way out. I haven't put that other purge valve in yet so I think I'm going to do that and see what happens with that before it gets cold. I've noticed that the pressure in the system is all over the place, sometimes 2 lbs then sometimes all the way up to almost 30lbs, enough to make the T&P valve dribble some. Last night I had a pretty good fire going and the floor temps were up around 70/72 degrees and as I was checking the manifolds I heard the pump change tune and it burped out a stream of water from the weep hole for a second or two then I could hear the pump trying to clear itself. I opened that bypass valve you suggested and after about 30 seconds it cleared itself out and calmed back down.

Then when I went over to the other side I could tell that air bubble had worked it's way into the HX where it was messing with the thermosyphen stream. I manually started both pumps and let them run for awhile until it worked it's way through. I don't know where it went but I played with it for awhile and it didn't pop back up last night.

Awhile back you said something about removing the dip tube out of the cold water tap on the tank. I've never removed one of those how do you go about that? And you mentioned relief valve......is that something different that the T&P valve?

 

[Raspy]

mx,

A relief valve is the same as a p&t, except it only relieves on Pressure and not Temperature or Pressure.

If you get a 26-99 you'll have more power than you need. They are three speed and you can run it on 1 or 2. A 26-64 would also be good and might be cheaper. Get either one in iron.

Pressure fluctuates as you describe if the pressure in the expansion tank is wrong. Too high or too low can do it, but it's probably too low. Drop the system pressure to zero and test it by putting a tire gauge on the schrader valve on the X tank to read the pressure. Pre-set it at 10 PSI with zero in the system. Use bike pump for this.

 

[mx842]

mx,

A relief valve is the same as a p&t, except it only relieves on Pressure and not Temperature or Pressure.

If you get a 26-99 you'll have more power than you need. They are three speed and you can run it on 1 or 2. A 26-64 would also be good and might be cheaper. Get either one in iron.

Pressure fluctuates as you describe if the pressure in the expansion tank is wrong. Too high or too low can do it, but it's probably too low. Drop the system pressure to zero and test it by putting a tire gauge on the schrader valve on the X tank to read the pressure. Pre-set it at 10 PSI with zero in the system. Use bike pump for this.

I don't have a relief valve in the system. I have one and a pressure reducing valve but they had been sitting a long time and both leak a little. Both look like they could be rebuilt if you could get kits for them, they are Bell & Gossett valves.

Yesterday I removed that air separator valve on top of my expansion tank and put a hose bib in it's place. I ran house pressure through it to the pump and opened and closed each loop one at a time and you wouldn't believe the crud I got out of each one. I think they were partially stopped up it took about 10 minutes on each loop to get clean water on both ends. I've flushed this thing several times and got some discolored water to purge out but never have I been able to free the loops of this much crap.

When I first started playing with this and had the stove in the other room all my piping and fittings were black iron. That was when I was trying to make the old boiler a updraft gasification burner. The old firebox was pretty good sized and I added a plate to the top of the firebox about 6 inches below the original top so that the smoke would have to exit out of the back of the stove. I cut a hole in the front part and put a sliding plate over it so I could give it a little natural draft to help with startup. Then in the back I built a secondary burner out of fire brick that the smoke and gas had to pass through to exit the stove. I added a couple air tubes at the entrance to the oven where I could inject air to get a secondary burn and that part worked pretty darn good I was getting 2200 to 2450 degree temps in the chamber depending on what kind of wood I put in it. The only problem was it worked too good for the old fire tube boiler that was originally on the stove and it didn't last very long before springing a leak and it was down hill from there. It also got so hot it burned off the 5/16 rod that controlled the damper where I couldn't slide the 5/16" plate covering the draft hole and later on even burned that plate out and after that I never could get much more than 1200 degrees out of it no matter what kind of wood I put in it. Thankfully winter was about over by then and over the summer I rebuilt the whole thing.

Then on the first real cold day I fired it with really good dry wood. I didn't have any controls on it other than a on and off switch for the pump and the way it worked was that as the stove made hot water it dumped into a 200 gal tank then was pumped to the manifolds through the black iron pipe. I planned to run it hard during the day and then just let the pump circulate the tank water through the system. Basically the pump ran pretty much all the time accept when I first fired it in the morning. Well this day I fired it and then a customer came in and we got to talking and I forgot about the pump and by the time I heard all the noises in the boiler room she was in chain reaction mode. The whole **** thing was glowing and had those little red sparks flicking off the sides like you see when you heat up a piece of iron with a torch. That old girl was popping and cracking and I didn't know weather to run or what. I ran.....of-course but thought about it and remembered that I still had the hose hooked up to the boiler but the thing was I had to get next to it to turn on the valve. It was hot but I managed to crack the valve and then turned loose of the kink I had in the hose to let some water in. Everything was alright for a bit then there was the loud CLANG, then a small Bang a little rattling then another really loud CHU CHU CLANG. Then I heard the stove pipe take off as the steam roared out the stack. That was the end of the up-draft gas burner project for me and I decided to go a little more down to earth approach to heating the shop.

Anyway I guess all that crud came from all that black Iron I had run through the system at one time. While I had the house water flowing through the loops the flow meters were reading great with 1.5 to1.8 gpm through all the loops in the first manifold and a little less maybe 1.1 gpm in the second part. That makes me think I'll have to replace those with what I should have put in in the first place. Once I flushed the system and had good flow through the loops I pressurized the system and turned on the pump thinking everything was going to be good but what I was looking at was the same old thing very little flow through the loops so I'm going to get a new pump as soon as I can and try that. But yesterday with a small fire the floor temp overall was up to 74 most places but it was pretty warm outside though.

Oh, and yes As I checked the pressure in the expansion tank it was too high. Around 19 psi. When I filled it last time I used the wrong air gage and it was way off. I have it reset now at around 12psi.

 

[mx842]

I have not posted in a while but hopefully everyone had a great Christmas and are enjoying the new year. There was nothing really worth reporting on because the weather had been so warm up until just after Christmas. Last week was a game changer and we got our first shot of real cold weather along with about a foot of snow. We had about 4 days where the temps didn't get above freezing and 2 mornings were right at zero. The coldest morning when I went into the shop it was 45 degrees in the coldest part of the building and around 52 in the center of the main part of the shop. The boiler room is always warm and on these two mornings it felt especially nice in there when I went in to check the stove. There were a few coals left and it didn't take long to get her going again. There was still 130 degree water in both the HX and the holding tank and in a short while I was making 160 degree water. The ave. temp of the floor was low to mid 50's and it took most of the day to get it into the 60's but the shop felt good. The next day was about the same as it was about the same temp outside right at zero. All in all I'm fairly happy with it. I never did get another pump to replace that old inline Taco but I'll have a new one before the next heating season. I replaced the seal in the old one and it seems to be holding water pretty good on start up and shut down but will leak some when an unexpected air bubble works it's way to it.

Thanks guy's for all your help and suggestions I learned a lot about my system and hot water heating in general from this process.

 

[Raspy]

mx,

I'm so glad it has been working out for you. If you feel like it, maybe you could post a few pix of the final arrangement.

I'm still making adjustments to my radiant setup that uses solar first and oil backup. Even with a good flow rate I had one room cool and had to figure out what was up.

I reduced the oil nozzle size to increase efficiency and am wiring in oil only thermostats to provide another level of control and minimize oil use. These will take over when the solar is depleted, if programmed to do so.

Now I'm chasing temperatures around on the floor and deciding what they mean while deciding on an optical switch or float for the low water cutoff.

There are lots of iron parts in my system and I was looking around last night for corrosion. None to be found. My corrosion inhibitor is working fine. I'm not connected to pressure water. There is a Harbor Freight sand blasting tank up in the loft that serves as an expansion tank and fill point for the entire system.

The beauty of hydronics is that you can arrange it any way you like.

 

[mx842]

I think the last pics I loaded were pretty much the way it is now. There are a few things I'm going to change but I'm not messing with it anymore this season. It's not perfect by any means but it's way better than it's ever been before. I know it sure is nice to be greeted by a nice warm feeling in the morning as I enter the door and not the cold chill I used to get when I went to the shop in the mornings.

Next year I want to put heat shields on the back and one side of the stove then loop my return water from the floor through the new heat shield before it enters the storage tank. That new T and valve setup the you suggested between the supply and return at the manifold helped a lot but it still could use a little help. I'm trying to decide if coming off the return line which is 1" cooper with a 1" X 1" X 3/4" T and routing the 3/4" side through the heat shield and back into the tank would help any. I don't know if that would work better than running the 1" straight through the heat shield.

Another thing I'm thinking about is adding a secondary oil fired backup to the system. I've been thinking about this for awhile and probably wouldn't use it much but it sure would be nice to not have to go out in the ice and snow to fill the stove when I am feeling lazy some mornings. I have this old steam genny that wasn't used much but when it was used it was abused. Anyway the pump finally gave out and it would have cost more to fix it than it was worth. It's had a nice 5HP motor on it that I used for my new Saylor Beall 705 pump for my air compressor setup and I still have the HX and the burner unit that I was thinking about somehow mating with what I have now. At first I had just thought about sitting the HX on top of the stove and forget about the burner but I got to wondering how that would work with the wood fire and the problems that come along with a wood burner. I don't see why that HX would not work to heat water for my floor I know it would make all the hot water you could use when it was a pressure washer. Anyway it's something to think about when I'm not doing something else.

 

[mx842]

I'm Back again.... Well it's almost heating season again and this year i'm in better shape time wise than I have been in the past couple years. I have most all of my wood cut and split and am putting the final touches on my powder coating project. The last big project for my powder coat setup was to build another small shed roof room off to the side to put my acid strip tank in and a place to keep a couple weeks supply of wood to burn off of when it's rainy or snow on the ground.

I had been also thinking of flipping my stove around adding enough length to the door to go through the boiler room wall to this other shed room where I can fill and vent the stove from there rather than in the shop. I'm trying to cut down on the smoke, dust and wood waste that I had to put up with before. I cut a hole through the wall and made it a little bigger so I could put in some heat shields and a way to insulate the opening to keep the high heat off the wood wall as much as possible and also fabricated a new front to the stove with the door extension and that part is done. I still need to build the door part and vent system but I need some more plate before I can finish that part.

With all this going on I decided that I would take that old 35 gallon water storage tank out and put the 50 gal one I had laying out back. This meant I had to re-pipe the whole thing again and hopefully this will be the last time. The only thing I don't like is I had to give up those two 1" thermostat holes that were in the side of the smaller tank but I'm hoping that it necking down to 3/4 in and out of the tank won't cause me too much restriction for my thermosiphon part to work. I guess I could cut new holes into the tank and weld larger bungs in but I'll see what happens this way before I do that.

After I got everything piped in and everything wired back up I ran both my pumps for a couple hours to see if I had any leaks and to see how much air I had gotten into the system. I had a little trouble with the water tank and HX but after a few minutes I got that straightened out then I opened the feed and return valves to the manifolds and started that old Taco pump and it ran as well. I was hoping I would have gotten a replacement pump for the loop system by now but just haven't gotten around to it yet. I still believe that is the weak link in my system right now and hopefully before it gets cold I'll be able to replace it.

I want to figure out how many BTU's I can get out of my HX and also, what kind of head pressures I'm dealing with in the two parts of the system but can't get my head wrapped around all those numbers and formulas to come up with that answer. I'm hoping that Raspy, Quicksandfarmer or Cal, can help me out with that part. I took a few pics of the new setup and will take some more now that it's piped in and post them when I get time. This setup looks a lot cleaner than the way I had it done before......Well I think so anyway.

 

[mx842]

Well it's been a long time since I started this and had planned on a follow up some time back but I got really busy. I thought I would post up the end results of how the system is working out. I worked on this thing for a long time trying to get this ol girl to working it's best. I re-plumbed this thing a half dozen times, routing water this way or that, putting pumps on either end of the system and finally ended up with something I could live with.

My biggest problem I had was I couldn't get the flow I needed to keep the air out of the lines. That Taco in line circulating pump just would not work no matter where I put it. I decided to junk that pump all together and start over. I found a larger series 60 Grundfos in line pump that has a larger pump cavity and a little more HP. It draws water right off the bottom of the tank and sends it over to the manifold. At the manifold I also put a smaller 3 speed grundfos pump just before the manifold as a booster. From there the water passes through the manifold and back to the very top of 55 gal water storage tank.

I'm still using the same heat exchanger as before and I have a small taco 007 pump circulating water through the heat exchanger and the water storage tank. I tried plumbing this several different ways but I finally left it to where the water goes into the HE out of the port at the bottom of the storage tank through the HE and out to the top side port on the side of the storage tank. This water heater has in and out ports on the very top and also has three ports on the sides. One is a drain all the way on the bottom that feeds the big grundfos. There is another port about 5 inches above the drain which feeds the little Taco 007 then over to the HE. There is another port about 5 inches from the top that I routed the heated water from the HE. This leaves roughly 4 inches of air space at the top of the tank I use for expansion.

There are three ports on the top of the storage tank. One I used for the return water, one I installed a 30 lb pressure valve and the last port I plumbed in a copper line with a ball valve in it. I use that to vent the tank if I need to drain and refill it and also if I need to bleed off some excess pressure the gathers at the top of the tank. Normally the pressures stays around 10 to 12 lbs but since I have been running the system a little hotter the pressures will build up to almost 20 lbs at times. When they get to that point I just open the valve at the top of tank and bleed a little off. It will do this for a week or two after I first fire up the system for the season then settle down to the normal 12 lbs or so from then on.

What really helped the most besides the larger pump Was that I bumped up the temp of the HE to start the 007 Taco pump at around 130/135. I have another temp switch on the outlet side of the 007 before it goes back to the HE and I have that one at 150/160 which starts the two pumps for the supply to the manifold.

I worried about dumping 160 degree water into the slab but it don't seem to mind. I really was worried more about the pex loops in the floor than the concrete itself but after checking the specs of the pex it should be ok. I think I read that it would stand 180 degrees at 100 PSI which is well with in the specs of the system. Running it this way I pretty much always have 125+ degrees water in the HE even when the big circulator shuts off. Both switches work on a 20 degree difference in water temp so that when the big circulators shut off there is still 125+ degree water in both the HE and storage tank which helps greatly with the creosote problem.

Actually I'm burning far less wood than I was before. In the daytime I throw in a few pieces of wood every couple hours with the draft open so it burns hot then in the evening I fill it up and wait until I get a good burn then shut the door with minimal air and at 10 o'clock the next morning there are still plenty of coals left for an easy startup for the day. I still get a little drip of water at the stack clean out but I can live with that.

I guess what I really wanted to say was is how much I appreciate all the help that I got from the guys here both the positive as well as the neg it all helped to get this setup up and running. My shop stays 70 on the warmer days like we have been having but even when it's 20 outside it still stays right at 60 inside.