Now that we’ve lived with it for a year, I have a few questions about the RFH. To save you time, I italicized the questions. This runs on longer than I expected.
Adjusting the heat has been a challenge. My one recommendation to anyone considering it would be to get really good windows. I told my contractor that I wanted energy efficient windows, but we can feel the breeze coming through them. He tried to save me money, but it ain’t working. So if it’s windy, it’s on the cold side. I have bought quilted material, and am making blankets that I can hang in the windows, right up against the panes. Has helped moderate the fluctuations. Contractor is family member, so can’t tell him to change them.
This warm/cold weather is also a challenge. I find that it takes too long for the slab to heat up/ cool down, so I just set the thermostat at 25°C (that’s about 77°F) Never change it, day or night, so take the covers off the windows at night to make it comfortable. If it’s really windy, leave the blankets on.
If I set thermostat at 70°, it will be too cold. Water won’t run enough.
There are hot spots in the basement, (3″ concrete slab). But not every 12″ or so, where the tubes would be running. There’s maybe 3′ of hot slab across the middle of the floor (on the short axis). Either side of that it’s significantly cooler, enough that you notice it through sock feet. Tubes are evenly spaced. Why would that happen, are the tubes not all sitting level in the concrete, so that in that area they are closer to the surface?? There’s also a spot on the main floor (another concrete slab) where it is hotter.
The RFH contractor said that the faster the water runs through the PEX, the cooler the floor will be.
So, I’m trying to make the bedroom cooler, and the bathroom warmer. I have the water running at the slowest rate right now. Should I speed it up to get less heat out of it for the bedroom? One word of advice — make sure they label your tubes. I have three runs in the 2nd floor, but don’t know which tubes are which!!!!!!! So it makes it harder to figure out which ones to run fast and which to run slow. With the long warm up/cool down, it’s difficult to tell if a change has made a difference, or if it’s just the change in the weather.
Damn, I guess I have more frustration than questions. I knew there was a long lead time to deal with weather changes, but I don’t like the fact that I can’t cool down the house at night.
Would I install it again. I don’t know. It sure is nice to not have the furnace blasting hot air at me. But I used to love turning up the furnace when I had my shower, and dropping it down at night. The extra cost of the concrete main floor, and the joists beams to support it will buy a lot of oil. Plus should have gone with ceramic floor which I would have hated, but there is a lot more heat comes through basement (unfinished concrete) than the other two floors. Engineered hardwood. RFH guy said that wouldn’t be a problem. I’m sure I’m losing efficiency because of wood.
That’s another thing. the boiler pump runs all the time. Is that more efficient than having it cycle on/off. The oil doesn’t fire up until it is needed, but the water is always circulating. I thought that would be more heat loss, but is that kinda like having a warm water recirculating loop to the kitchen so the HW is always there??
During the summer one of the valves stuck open on the RFH, so the bloody heat was circulating upstairs for a few days. I kept thinking it was kinda hot, but didn’t even think about RFH being on (DHW runs off boiler, so furnace running is normal) Finally heard the tick-tick-ticking of heat expansion, ran downstairs, felt the hot pipes, and swore. RFH contractor said it probably only ran for 45 secs, something about it cycles once every day just to keep the pipes open. Hunh?? Should it open every day, even in the summer. We shut the main valve off to stop it. Who wants the RFH running when it’s 80° outside?
There are little thermometers in the adjusting tubes — I can read them in one set, but the other set is too opaque to read. Water is coming back at 90° (sorry, don;t know what it’s going out at.) Do I want to get it lower. Should the contractor replace the adjustment thingamajigs that I can’t see through?
Well, this is longer than expected. I know long posts don’t always get replys. I hope someone will respond. Thanks it advance.
Replies
This isn't really much of a response. I just wanted you to know that I've saved your message in my When I Build my House directory.
I did have a thought about the three unlabeled loops. Could you shut off two of them at a time and see which rooms/areas cool off and which ones stay warm?
Shame about the windows.
I think these gotta be addressed piece by piece to avoid confusing them. I'll start with two, and others might fill in the others.
Do you have an outdoor reset on the system? It anticipates temp changes and makes automatic temp adjustments. In a low mass house or one with significant air infiltration such as you describe, I'd want that to give the slab a head start. In a high mass and/or tight house, it's less necessary. That would help you with the hot/cold not being synchronized to desired room temp.
For hot and cold spots on the slab, would have to see the tube runs. From the supply side, do they first run the perimeter of the floor, rather than the center of the floor? Most heat loss will be near the edges, so if that's getting the backside of the tube run, then an area with greater loss is getting less hot water and that's one possible explanation for why the center of the room is warmer than the edges.
>The RFH contractor said that the faster the water runs through the PEX, the cooler the floor will be. So, I'm trying to make the bedroom cooler, and the bathroom warmer. I have the water running at the slowest rate right now. Should I speed it up to get less heat out of it for the bedroom?
I'd want someone smarter than me, like David Thomas, to comment on this one, but I'll partially address it. I don't think it's true that fast water means cooler floor. High flow rate means the return water will be a higher temperature be/c there's been less time for heat transference, but you're making up for that with more hot water, so the tube always has hot water, so the floor will get hot. Consider the opposite. Slow flow. The part of the slab near the supply sucks all the heat out and leaves none for the rest of the loop. Result is cold flow. The answer is that the flow has to be set to the level that will achieve optimal heat transference, which can be measured by delta t...the difference in temperature between the supply and return. Neither too fast nor too slow results in a balanced system.
Which leads to the last part of the question. If I wanted to make the bedroom cooler and the bathroom warmer, and they were on the same zone, I'd close the valve to the bedroom a bit and open the one to the bathroom. Put more btus where you want the greater transference of heat.
I'll change/delete this last section if contradicted by David...but I think it's ok.
mart.... it sounds like the guy who designed and / or installed your system didn't and doesn't know what they were doing
RFH and, for that matter, any kind of heat is an absolutely predictable system..
the insulation of your envelope is part of the system..
the ambient heat of the outdoors is part of your system.. the temp setttings on your boiler, the flow rate of your water, the sizing of your tubing, and the layout and labeling of your tubes.. all has to be planned for..
now.. you have to reverse engineer the damn thing and find out what has to be tweaked
sorry , buddy... this is not the way it's supposed to be, you need some competent help
edit: disregard all my above.. just do what sam & cloud have outlined..
and shoot the guy who who suggested switching your windows
Mike Smith Rhode Island : Design / Build / Repair / Restore
Edited 1/9/2005 12:28 am ET by Mike Smith
>The RFH contractor said that the faster the water runs through the PEX, the cooler the floor will be. So, I'm trying to make the bedroom cooler, and the bathroom warmer.
"I'd want David Thomas to comment on this one. I don't think it's true that fast water means cooler floor. High flow rate means the return water will be a higher temperature be/c there's been less time for heat transference, but you're making up for that with more hot water, so the tube always has hot water, so the floor will get hot.
Correct - Fast water flow will give you MORE btu's delivered. It is a higher mass flow rate. The flow will be more turbulent which always gives better heat exchange. And the high temps will reach further down the tubing, quicker, at high flow rates.*
*However, there are often pratical limits to the flow rate. About 2 psi of pressure drop will move 2 gpm of water in a 100' foot length of 1/2" pipe. To double that flow to 4 gpm, you must quadruple the pressure to almost 8 psi. Stepping up to 10 gpm would require 35 psi and circ pumps don't make those pressures.
Jim may be on to WHY the RFH contractor would say something stupid like "the faster the water . . the cooler the floor" Heating guys tend to think in terms of delta Ts, for instance, 10 degrees cooler water returning as a design guideline. Faster flow gives lower delta Ts. But really, they should think of delta T times the mass flow rate (or GPM if you prefer). Total BTU/hour going out - total BTU/hour coming back = BTUs delivered. And faster water flow will increase that slightly.
If I wanted to make the bedroom cooler and the bathroom warmer, and they were on the same zone, I'd close the valve to the bedroom a bit and open the one to the bathroom.
Jim, I agree with that if you have separate loops for those rooms. Just like a forced air sytem has balancing valves to deal with hot and cold parts of the house. Note that flow will be VERY insnesitive to valve position through most of it's rotation and all the control will com in that last little bit of movement before it is completely closed.
The easier to operate (but more expensive to install/modify) way to control the temp in different areas would be to send lower temp water to the one that is too hot. i.e. install an additional tempering valve.
Or, if one zone controls two loops (hopefully), just separate the loops, install another pump and another t-stat.
But wait a minute! A zone can't get too hot - it's t-stat should stop the flow of RFH water. So it must be PART of a zone that is too hot. Hopefully, the too-hot part is where the RFH water goes first and the too-cold part is where the water flows next.
If part of a loop is too hot, simply reverse the direction of flow in that loop. That will help. Do that first.
Beyond that, you could get fancy and increase the water temp and run water for only one gallon at a time (100' of 1/2" holds one gallon) - about 20 seconds. Then wait a few minutes and repeat. So most of the heat will be delivered to the front half of the loop. And the second half of the loop will get the water once it has lost much of it's delta T. A non-latching on-delay relay might do that cycling for you. An interval timer certainly would. About $55 in Graingers.David Thomas Overlooking Cook Inlet in Kenai, Alaska
Maybe the hot / cold rooms came about because of different floor coverings. And a qay easy adjustment would be to throw some area rugs in the too-hot room. The added insulation will decrease the BTU/sq ft the floor delivers. May not be enough to completely fix it but it would help and it very easy.
Personally, I think about what areas SHOULD be warmer (baths, entries with snowy boots, changing rooms) and cooler (bedrooms, wine storage, etc) and I run loops first to the warm rooms and then to the cool rooms. So that 1-3F difference between rooms is in the direction I want.
I also make a scale diagram of where all the tubing is. If you tie it to the 6" x 6" #10 WWF, the right sized graph paper makes the sketching go really fast. Your mileage may differ. Your RFH guy may not care about quality work or may lack the intellectual firepower or rigor to understand the important concepts. If you EVER have to modify the loops, you'll wish you had that diagram. Even for troubleshooting like this, it helps a lot.David Thomas Overlooking Cook Inlet in Kenai, Alaska
>I agree with that if you have separate loops for those rooms.Thanks for the response. I always learn from you, David.I think from his descriptions that he has this setup. I'm not going back not to read because my daughter's begging for a game of pool, but my recollection is that he doesn't have separate temp controls on each room, and no way to vary the loop temp separately. It's the same as my setup here, as I recall, so the suggestion was the same as the one for us from Wirsbo.Everything ok in Kenai?
I think this is his setup
View Image
Fed from two control valves, maybe preceded by mixing valves. 7 flow valves on the return side.
SamT
RFH works very well, assuming it is designed and installed properly. It is less forgiving of mistakes than other systems. From what you describe, it sounds like you have a problem. First of all, pumping the water faster does not mean less heat. Each gallon of water going through the pipes carries "X" amount of BTU's at a given temperature. The more gallons are being introduced into the pipes, the more BTU's. That doesn't necessarily mean that all of the BTU's are being transferred, but "speeding up" the water will NOT cool down the floor.
As far as uneven heating, there could be many reasons, but one of the most likely answers is that the tubing closest to the boiler gets the hottest water, and so normally it is run around the perimeter of the room, where heat loss is highest. If the supply side of the loop is in the middle of the floor, you would almost certainly notice a difference from the middle of the room to the edges. Sometimes this can be solved by simply switching the supply and return at the boiler, but I would only do this if you KNOW this is the problem.
Whether or not 90 degree return water is normal depends on too many factors to be simply explained.
It sounds like a system that needs to be balanced by an expert. As Cloud said, it definitely should be on an outdoor reset control.
I am having trouble replying, live in boonies, on dial-up, only one hour per day, and this is third attempt.
Outside reset - - I rely on weather forecast. Wasn't an option, though I did know about it from here.
Basement is rectangle, Hot spot is in middle across short axis. One tube likely comes to middle and works back to boiler. OTher likely goes to middle, and across to far side. The pex runs back and forth across short axis, the hot spot is where they meet, so that's likely explanation. Never enev thought about it. like that.
House is thermal mass. Basement poured foundation, Insulation is on OUTside. Above ground walls have sprayed foam, with rigid insul on outside to reduec thermal leaks from framing. should have continued the rigid insul across the windows.
Flow rate is .25GPM. Returning water is 70 - 80°F. I think outgo is around 105. Just remembered, mixing valves inside control box. I have 7 lines, controlled by two mixing valves. Hmmm, maybe I could get some control there. But the bedrrom and bathroom are controlled by the same mixing valve, just have separate flow rate controls.
Thanks for replys. Sorry short reply by me, but my IPS might disconnect me soon.
>But the bedrrom and bathroom are controlled by the same mixing valve, just have separate flow rate controls.Good, that's the situation I described, and lessening the flow to the bedroom, or increasing it to the bath, or both, is how I'd first try to balance the rooms. It's the least complicated approach. Just note where it was set be/f your experiment. In some systems, you count the number of turns of the knob from a closed position. In others there may be a gauge.>returning water is 70 - 80°F.If the water's that low, you can assume that it's not effecting a heat transfer near the end of the loop, be/c there's not a great enough difference be/t the water temp and the slab temp. If the slab was at a proper temp (I aim for 10° above ambient as a rule of thumb--only a rule of thumb), then there could even be a heat transfer from the slab to the water!!! Maybe the water's not hot enough, maybe the loops too long, maybe there's too much edge loss, maybe, maybe, maybe. But _something_ is sucking out the btus faster than you're getting them in there, it seems. I think there's consensus that at the very least, you gotta heat the perimeter first, which as Nick points out, could be as simple as switching supply and return.Don't feel bad about this...my house took a year or so to balance properly...till I understood how the house responded to various conditions and got the flows and water temp and tstats set properly. And then 3 years later we dropped the set point from 115 to 105 be/c we learned that the hotter water wasn't doing anything but making the heat pump work harder. Now, it's pure bliss. Completely comfortable in every room and completely automated...I don't do a thing but look every now and then to make sure it's hitting design temps and make sure dw hasn't changed a tstat.
Edited 1/8/2005 11:45 pm ET by Cloud Hidden
Martagon,
Right now, as soon as you read this paragraph, scroll down and check and see if this message is truncated. if it is, click on 'vView Entire Message. Click on 'File' at the top of your browser and then click on 'Save As'. A window will pop up Named 'Save Web Page' with a box called 'Save In'. There is an icon of a Folder with an up arrow on it to the right of the 'Save In' box. Click on that icon until 'Desktop' shows in the 'Save In' box. At the bottom of the 'Save Web Page' pop up, there is a box named 'Filename'. Type a good name in there and click the 'Save' button on the pop up.
Ya done?
Now you can surf or check your Email or something, 'cuz this page is on your Desktop. Write your answer in Notepad or Word, then tomorrow, when you go online again, you can cut and paste your answer in.
Thermostats have a differential between turn on temp and turn off temp. For instance, if you have the heating thermostat set at 70*, it should turn on the heater at 69* and turn off the heater at 72*. With RFH, you want that difference to be close, like 2 or 3*. See how far you have to turn the thermostats between the on click and the off click. You may have to listen close or open it up to see the mercury fall on and off the electrodes in the mercury switch vial.
Mixing valves set at 105* is probably OK.
First you got to lable all the flow valves. Record the temperature in each room and roughly map out any cold spots on the floor for each room. Don't mess with the thermostats. BTW, how many thermostats have you got.
Pick one flow valve, any one, then, for each valve, one at a time, do the following:
Crank the flow valve wide open. Count the turns so you can put it back.
wait 5 minutes and see which return line gets hotter.
Wait 30 minutes to an hour and check the temperatures in each room to see which room is getting hotter and losing it's cold spots.
Lable the flow valve and return line.
Put the flow back where it was.
Repeat this for each flow valve.
Now, this has taken most of a day and you're probably ready for a break, so go down to your local pet store and buy 7 stick on aquarium temperature strips. Get the kind that measure 80* to 100*. Stick one on each return line. If you don't do that, find some way to measure the temp at each return line. Even if it is one at a time. This is important.
Now that you have identified each flow valve and return line and can measure it's temp, you are ready to balance the system. We're going to try and do this in one day, so break out the sweaters and long johns. We will try to do it tomorrow if it's cold enough, so tonite, turn down the thermostats to 65*.
Good morning.
Turn the thermostats up to 80*.
Wait 30 minutes.
Check the return line temps
Write them down.
We're shooting for 90* return temps. when the temp is 90* leave that flow valve alone, 'cuz it's set for now.
Open each valve, as needed, a little amount, (all the same amount.)
Wait 30 minutes.
Check the return line temps
Write them down.
Open each valve, as needed, a little amount, (all the same amount.)
Repeat as needed until either
You get 90* on all the return lines, or
The house temp gets to 80*.
If the house gets to 80*, turn the thermostats back to comfortable and we'll start again tonite, by turning the temp down to 65* when you go to bed.
When you get all the return temps to 90*, set the thermostats where you normally like them and wait two days or until the system stabilizes. Don't touch the thermostats during this time. You have to wait and see what these settings do.
Now you have a baseline. This too is important.
Leave the thermostats at the comfort setting. Where you have masonry floors, like the basement, set the flow rate so the return temps are 15 degrees hotter than the thermostat. Where you have wood or carpet, set them 12* hotter. This takes another day or two. Follow the previous steps.
Remember that all this has to be done during heating periods, so if you get a warm spell, you will have to pause the process. Don't mess with the thermostats, however.
OK, now the system is stable and balanced, but it's not set for comfort, so we'll do that now.
First check the two flow meters and make sure that the total flow is between 1/4 and 3/4 of the pumps rated flow. Email me by clicking on my name at the top of this post if it's not.
Check the temperature in each zone/room and record it. Also record the temp you would like in each room.
If all the rooms in a thermostat zone are too hot or too cold change the thermostat until some are warm and some are cool.
If two rooms are on the same flow loop, either pick one or split the difference.
To raise the temp in a flow zone increase the flow until the return temp rises 1* or 2*. You have to experiment.
To lower the temp, decrease the flow to that zone the same 1 or 2*.
Remember that your thermostats measure the average (sorta average) temp of the whole area they serve.
Wait 24 hours.
Check the temperature in each zone/room and record it.
Adjust flow rates as needed.
Repeat until all rooms/zones are where you want them.
Take your time, take notes, have fun(ha ha) and good luck.
SamT
Edited 1/9/2005 12:10 am ET by SamT
Wow, Sam, thanks for such a detailed plan. I've printed it off so that I can go through it step by step.
I didn't used to have such a problem with the computer and doing messages,, but I had the store install a hp1310 printer/fax/phtocopy unit, and now, i can only go on'line once each time the 'puter is started up. Used to be I could go on and off as much as I needed. Something in the fax, I think, is auto-answer, so I can only go on-line once, then the computer thinks the line is busy, so I have to re-boot to get back on. Gets long And tedious, I vaguely remember seeing a tab for auto-answer in the set-up for fax, but can't find it again. I think if I could shut it off, we might be ok.
thanks also could and mike. No-one touches the thermostat except me. The house is really warm to-day, but it's 32° out, no wind. I can't turn it down too much in case a cold snap hits.
Here some stuff I pulled off our site...use what works and makes sense to you.
Didn't want to post the links...I think its called self promotion.
RB
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Radiant Systems Design Information:
Design delta t's ( the difference between the inlet and outlet ) influence flow.Pipe diameter influences flow velocity.Velocity influences head losses.This influences the circulator selection which is why flow is a hydraulic issue.However, heat transfer is a thermal issue which is influenced by, temperatures, resistances and surface areas.The greater the heat transfer surface area the lower the average fluid temperature. The smaller the heat transfer surface area the hotter the average fluid temperature.Thus the wider the spacing the less surface area and need for higher average fluid temperature, the narrow the spacing the more surface area and thus lower the average fluid temperature.This why baseboard or wall mount radiators need higher fluid temperatures than radiant floors, walls or ceilings. However if the tube spacing is fixed in the design, the reduction in surface area, i.e. from 7/8 to 5/8 to 1/2 or 3/8 results in a need for nominal increase in fluid temperature. A few degrees per size reduction. The relationship between the hydraulics and heat transfer is in the average fluid temperature which is based on the delta t.The larger the design delta t - the less flow is circulated resulting in a lower average water temperature. A system designed for an average water temperature of 100 deg F and 20 deg F delta t needs 110 deg F supply and anticipates 90 deg F return at maximum load.But the same 100 deg F average can be delivered with a 30 deg F delta T ( less flow) simply by raising the supply temperature from 100 deg F to 115 deg F. Both deliver the same Btu/hr but the hydraulics are different.So reducing the flow with a larger delta t, but raising the fluid temperature delivers the same amount of heat but in smaller diameter pipe. (all things being equal)The question then becomes what is the consequence of a larger delta T?In a highly conductive thin, low mass embedded system with low R value floor coverings piped in a serpentine pattern it is a big deal. Its possible to feel where the tubes are and notice a temperature change across the floor.But a large delta t design in a high mass, less conductive system pipes positioned low in the slab and in a counterflow pattern with relatively higher R value floor coverings...its not a big deal because the heat is allowed to diffuse horizontally through the slab.So delta t selection, pipe diameter, tube pattern layouts are not arbitrary selections.In fact the smaller the load and or the smaller the area the bigger the problem because good design practice is to select pipe diameters to maintain flow velocities between 1.5 and 5ft/sec whilst staying between 1ft to 4ft of head per 100 ft of pipe. Small loads with large delta t equates to less flow. Any pipe diameter selected which results in low velocities introducing potential for air separation, air locks and sediment buildup. Any pipe diameter selected which results in high velocities introducing potential for erosion corrosion, noise and equipment damage.This is why designing hydronics is not for the DIY'r .... as the more capable individuals posting above have learnt from experience - those who dismiss the engineering principals as making things "too complicated" .... are usually the ones who create the problems for the end user and anyone else called in to troubleshoot a bad system.____________________________________________________________
This is one way to understand the relationship between flow, temperature and velocity...take from it what makes sense to you.The quantity of heat to be replaced is carried by the flow...(flow is a container per unit of time)Think about the last time you had to wait for a train crossing. There could have been a single rail car or 100 cars.The train could have been speeding by at 60 mph or painfully slow at 4 mph. The cars could have been empty or carrying water. The water could be hot or cold.The average water temperature in the tanker cars is the fill temperature reading from where the train started its journey minus the temperature reading from where the train stopped at its destination, divided by two.All things being equal if the train travels slower the average temperature will be lower. If the train travels faster the average will be higher.Remember its the difference in temperature which drives heat transfer...so if the fill temperature reading and the destination temperature reading are the same then there was no heat loss along the journey because the temperature outside the tank was the same as what was inside or possibility the tanks were well insulated.Now image that one Btu is equal to the amount of heat a single wooden match puts out.A load of 20 Btu/sf/hr is the same as burning 20 matches in a 12" x 12" area every 60 minutes.In our example, the rail cars are essentially carrying matches. The more matches in the tank, the hotter the water.The less matches in the tank, the cooler the water.The bigger the tanker car the more potential matches could be held.The smaller the tank the less matches could be held.If a tanker train is full of matches then you potentially need less tanks or smaller tanks or the train can travel slower.If the tanks are half full of matches then you need more tanks or bigger tanks or it has to travel faster.When we do a heat loss we are determining how many matches we need per hour.When we do a flow rate calculation we are determining the combined volume (gallons) of the tanks and the frequency (per minute) that they have to come by to deliver the matches. (think fire fighting bucket brigade)We can reduce the number of tanks by increasing the size of the tanks or by increasing the number of matches each tank carries. Increasing the size (surface area of a tank) is like having closer tube spacings in the floor. Increasing the number of matches in the tank is like raising the temperature of the water.Slowing down the flow is analogous to slowing down the train...you won't get anymore heat unless you load each car with more matches (ie: raising the temperature of the water) and/or increasing the size of the tanks (more footage). A floor which can't achieve design conditions is one where the fluid temperature is too low, the flow is too slow, there is insufficient tube footage, the boiler is under sized, the heat loss was inaccurate, the R-value of the floor has changed, and the downward loss is greater than anticipated or any combination of the above.
__________________________________________________________________
Hope some of it makes sense to you.
RB
rb..great post... i forgot about the anlogy of the match / btu
what's the name of your company.. got a link ?Mike Smith Rhode Island : Design / Build / Repair / Restore
Mike,
Nice site.
http://www.healthyheating.comKK
Thanks Mike,
I wish I could reach every person before they install radiant...with the right information and the right installation accompanied with a good ventilation system its the greatest way to condition a home enviroment.
Stay well - stay warm.RBean
http://www.healthyheating.com
http://www.healthyheating.com/blog
thanks .. great looking site...i've bookmarked it..
our just-finished job was RFH.. the homeowner did it all... i was pretty impressed with his work.. especially since he had never done it before..
but 30 years of building paper mills helped him over the humps... and my 30 years of watching plumbers and HVAC guys didn't hurt either Mike Smith Rhode Island : Design / Build / Repair / Restore
OK, I've printed off the longer articles, bought a couple of aquarium strip thermometers, and am going to study!!
There are two thermostats (one for basement and main floor; one for upstairs). Of course, basement should be on its own, 'cause there are only two little windows, and the air infiltration is very low.
There are two temperature adjusters, one for the B/MF, one for UP/S; there are two loops to the basement, two to the main floor, and three to the UP/S. Each loop has a flow rate adjuster (at the return end), and then there is another adjustment at the sending end.
You know, I think that I could really mess this whole system up. So, I will take this very slowly.
Martagon,
You got two thermostats. What do they turn on and off? Have you got two pumps or two electronic valves?
SamT
Ah, I'm guessing I have two elctronic valves, and one pump.
Can anyone tell me why he said the valves had to open for 45 sec every day -- therefore the running in the summer.
Based on your description I would think that you have the flow reversed!
Water will flow either way thru a tube so what I would do is start the hot water at the outside and pick the cooler water up from the inside . Based on your description
it sounds like you have the hottest water going to the center and take the coldest out at the edge..
Seems to me that the water flow in the loops where you're feeling the intense hot spot is far too low. Water is flowing in, losing all its heat in the first few loops of tubing, and returning water to the boiler near room temperature (70-80 F).
Increase the water flow to those loops in the slab. There's precious little sensible heat in 0.25 gpm of water even if it's quite hot. If the flow is too low, the slab will soak it up in the first few loops and leave nothing to heat the rest of the slab. If the particular room gets too hot relative to others, you need to reduce the inlet water temperature on that loop, not decrease the flowrate through that particular loop.