0014 Taco too fast?

[ken999]

It seems that the cold weather last week gave my first floor baseboard quite a workout. I couldn't push the temps up an higher that 73 with 'teen-ish' daytime temps.

I've got an 80' run of 1 1/4" Thermopex from my CB e-Classic 2300 to the house. My boiler is set on 185 for an upper limit.

Any thoughts?

 

[Gooserider]

Insufficient data.... There is a Taco tech paper on pump sizing I point at in the "Tidbits" sticky - I'd start by running the numbers through that and see what it suggests.

I would also try to get temp measurements of the ACTUAL temps at the boiler supply and return, and at the house side supply and return...

If you have much difference between the boiler and the house - no more than 1-2°F on each leg, you have issues with your Thermopex runs...

Then look at how much difference there is between the house supply and return temps - how close does it come to matching your "design day" estimate for ΔT - 20°F is fairly typical if you don't know just what it should be...

If it's significantly less, that would suggest that your flow rate is to high, and you are pushing the water through the system to fast for it to transfer heat effectively

If it's significantly more, then it suggests you need to increase the flow rate, as you are pulling more heat out than was intended.

If it's about what you expected, then it suggests that you're heating system is working as it was designed, but your house is loosing heat faster than the heating system can supply it - either improve your insulation and weathersealing, or add more heat emitters...

Gooserider

 

[ken999]

Thanks GR.

I'll have to run some numbers and get some readings on my deltas. Would and IR temp gun be sufficient or do I need to install inline sensors?

 

[TCaldwell]

for what you are describing a ir gun should get you in the right direction

 

[Gooserider]

Thanks GR.

I'll have to run some numbers and get some readings on my deltas. Would and IR temp gun be sufficient or do I need to install inline sensors?

An IR gun would get what you need as long as you are using it when everything is cycling, and are consistent in the way you shoot the connections, but I will say that I'm personally a fan of doing some kind of ongoing monitoring - good diagnostic and early warning if there are problems, etc...

Gooserider

 

[jduke]

Gooserider, read this post and had questions? I have a cb5036. Runnng to water heater heater then to forced air furnace. I have the boiler set at 180. Return temp. is @ 130 while furnace is blowing. When furnace blower is not blowing-return temp. is 10-15 degrees loss. Is this ok? Thinking i may need to add a larger pump????

 

[MNBobcat]

Menards sells the Grundfos UPS26-99FC which I consider to be a much better pump than the 0014. It has the same flange mounting as the 0014 so its a direct replacement. However, the 26-99 can handle a high head (up to 29) and it has 3 speed settings. Flow range can be up to 33 gpm. It gives you the advantage of running it full out if you need the GPMs but you can also fine tune your system by trying lower speeds. If the lower speed works for you, you also save on electricity costs. Honestly, with the speed settings and the easy availability from Menards I wouldn't even consider the Taco pumps. Menards sells Tacos too if you really want the fixed speed pump. The 26-99 falls in the range of the taco 0011 and 0014 (depending on speed setting) if you want to be able to compare it.


I designed for ΔT - 20°F at I'm seeing ΔT - 15°F and my house is much more comfortable with the boiler heat than it was with propane. My furnace runs about the same or less than before I installed the boiler. I'm running my pumps on high speed right now. When I have time, I'll try slowing them down and I know I could gt ΔT - 20°F by doing that. I could not be happier with my system. I'm heating a 7,000 sq ft home. Wood consumption on my OWB hasn't been bad. We'll see what happens when I add my garage heater this weekend.

 

[Gooserider]

Gooserider, read this post and had questions? I have a cb5036. Runnng to water heater heater then to forced air furnace. I have the boiler set at 180. Return temp. is @ 130 while furnace is blowing. When furnace blower is not blowing-return temp. is 10-15 degrees loss. Is this ok? Thinking i may need to add a larger pump????

That sounds like a really HUGE amount of loss in your lines - unless there is some other load that is contributing to the drop. To isolate I would suggest measuring at each end of the house lines - i.e. at four points - where the lines enter and leave the boiler, and where they enter and leave the house - that way you will be seeing just what the drop is from the lines.

I would also say that settings don't matter that much in this context - the key questions revolve around what are the ACTUAL temperature readings - if you don't have actual readings you are groping around in the dark - might find the GF if you're lucky, but may end up in the pucker brush just as easily... It is why folks like NoFo and I are so big on wanting instrumentation - If you haven't measured stuff, you don't know what it's doing...

That said, assuming that you actually have a drop of 10-15°F in your lines - and guessing at a 20gpm flow - 20 x 8.33lbs/gal = 166.6 lbs/min x 10°F = 1,666 btu/min x 60 = 99,960 btu / hr at 10°F drop, or 149,940 btu / hr at 15°F - call it 100-150 Kbtu / hr going into making the ground warm :grrr:

Assuming a 180 - 130 = 50°F drop when the house is heating, or approximately a 500 kbtu / hr TOTAL demand - you are dropping 20-25% of your boilers output into the ground - hope you like chopping wood...

This is the reason why we put so much emphasis on the need to really insulate the lines - even small temperature drops add up to big btu loads. From what I've seen it doesn't really seem possible to get below 1-2°F drop, which would still work out as a 10-20Kbtu/hr load at 20gpm, but that is still a lot better than what you seem to be suggesting...

Note that using a different gpm flow rate will change the actual numbers, but it WON'T change the ratio between whats going into the house vs. whats going into the ground... The ONLY way to improve loss rates going into the ground is to improve the insulation on the pipes....

Changing the pump won't change the load drops that much, though it MIGHT help your return temps - which are on the low side - however you would want to work the numbers in that pipe sizing paper I keep pointing people at in order to see if you have enough flow capacity in your lines to take advantage of a higher output pump. You will also want to make sure that your boiler has the output capacity to supply BTU's at a higher rate - otherwise you will be pulling heat out of the boiler faster than it can produce it, which will drop the supply temp, but not do anything for the return.

Gooserider

 

[jduke]

Gooserider, I'm using cb's thermopex. I'm measuring the line temp. entering my water heater's flatplate exchanger(180) and returning line temp from furnace exchanger(130) . All temperture readings are taken after lines are out of the ground. I'm only losing 1-2 degrees between cb5036 and water heater. The only change i've made this year is a 100 gal water heater with dual flatplate exchangers. I didn't monitor incoming temps. at water heater last year so i can't compare the change. I have ample potable hot water. I think i'll check the temp loss across the water heater and see what loss is there. I can by-pass the second flatplate and gain some line temp. I'm still getting at least 12-14 hours burn time while daytime highs are 18-22 and nite-time lows are 5-10. Just trying to save some wood!! thanks

 

[Gooserider]

Gooserider, I'm using cb's thermopex. I'm measuring the line temp. entering my water heater's flatplate exchanger(180) and returning line temp from furnace exchanger(130) . All temperture readings are taken after lines are out of the ground. I'm only losing 1-2 degrees between cb5036 and water heater. The only change i've made this year is a 100 gal water heater with dual flatplate exchangers. I didn't monitor incoming temps. at water heater last year so i can't compare the change. I have ample potable hot water. I think i'll check the temp loss across the water heater and see what loss is there. I can by-pass the second flatplate and gain some line temp. I'm still getting at least 12-14 hours burn time while daytime highs are 18-22 and nite-time lows are 5-10. Just trying to save some wood!! thanks

OK - if you are dropping the BTU's in the house, that is a lot better - at least you are getting something out of them... Thanks for the clarification. (I would still verify that you aren't dropping more than you think in the buried lines - I'm not all that convinced that Themopex is as good as CB claims - perhaps it's something to do with the source of the claims....)

Now having a good ΔT has it's virtues, but it suggests that you aren't moving ENOUGH flow through the system - you are pulling more BTU's out of each gallon of water than you want, which means that you need more gallons. However, depending on the head figures and flow resistance of your lines, you may not be able to get significantly more flow out of your pipes - a common problem w/ remote location boilers, which is why I keep pointing at that Taco paper on pump picking in the tidbits sticky - it also goes through figuring head resistance and how that figures into pump selection...

If you can't bump up the flow, then you will have to work on the other end to see what you can do about reducing demand - and to accomplish that you need to start by figuring out just where the demand IS, which means measuring the drops across each part of the system.... (and this includes pipe runs, how well insulated are the pipes in the basement?)

Gooserider

 

[Nofossil]

I'll agree with GR that you need to get data over time. a 50 degree delta T is really large, but not unheard of as a momentary situation when an indirect DHW calls for heat or when a cold zone opens up. Steady-state values when everything has been running a while would mean more.

It does sound like the flow rate from the boiler is too low. All other things being equal, lower flow rates mean higher delta T. Does the boiler have any difficulty keeping up?

 

[MNBobcat]

He has 1 1/4 thermopex on a short run and should be able to move a lot of water. More than I can. My run is about 275 feet from the house to the boiler. I'm also using 1 1/4 thermopex.

That 1 1/4 thermopex won't do you any good though if you have everything in the house run in series and you're reducing down to 3/4 of an inch or 5/8 of an inch at your furnace heat exchanger. You'll kill the flow rate. I've read that you need 10 GPM for a 100,000 BTUs.

I would recommend you run to Menards and pick up that grundfos 26-99 pump that I told you about. Try it and see what happens. If you don't see a vast improvement, take it back.

 

[ken999]

Allrighty...Here's some numbers. I finally got my hands on an IR thermometer.

I kept getting wierd readings at the boiler so I concentrated more on what was going on downstairs. I have 80' of 1 1/4" CB Thermopex from the OWB to the house. My boiler is set at 185 and it has a 5 degree differential, kicking on when the water temp hits 180.

Inside I was reading 179 coming through the wall with 172 going back out. From there I have a 40' or so run to the oil boiler. These supply and return lines in the basement are yet to be insulated as they keep things 68ish with the bottom of my FF subfloor reading a nice 70 or so. Come warmer weather I'll likely wrap these pipes up when I'm just trying to heat the domestic water.

From the oil boiler, I'm sending out 176 on the 3/4" pex and getting back 152 after 6 8' baseboards on the FF. Things look pretty consistent with 4 degree drops after each 8' BB.

The IR meter seems a little fussy and it takes some monkeying with but I think my readings were decent. Not as good as in line metering, but it's a start.

 

[Gooserider]

Allrighty...Here's some numbers. I finally got my hands on an IR thermometer.

I kept getting wierd readings at the boiler so I concentrated more on what was going on downstairs. I have 80' of 1 1/4" CB Thermopex from the OWB to the house. My boiler is set at 185 and it has a 5 degree differential, kicking on when the water temp hits 180.

Define "weird readings" - might be a clue, might be a problem w/ using the thermometer...

Inside I was reading 179 coming through the wall with 172 going back out. From there I have a 40' or so run to the oil boiler. These supply and return lines in the basement are yet to be insulated as they keep things 68ish with the bottom of my FF subfloor reading a nice 70 or so. Come warmer weather I'll likely wrap these pipes up when I'm just trying to heat the domestic water.

Size of the pipes on that 40' run? Actually we could probably use at least a rough sketch of your entire setup - I'm not sure just what you are doing in the house.
Depending on the actual boiler out temp at the time you took the house side reading, it doesn't sound like a terrible temp drop in the Thermopex... But then you only have a 7°F drop going through the rest of the house, which suggests you might be pumping to fast...

From the oil boiler, I'm sending out 176 on the 3/4" pex and getting back 152 after 6 8' baseboards on the FF. Things look pretty consistent with 4 degree drops after each 8' BB.

This is where you are losing me... :-S 176°F at the boiler sounds fairly reasonable as its about half the drop reported above. The part about a drop from 176 - 152°F on the boiler loop also makes sense, and is a close enough fit to the standard 20°F drop that most folks use. Only thing is that a 3/4" line is seriously restrictive compared to the 1.25" line going to the oil boiler... The problem is how do you get from 152°F boiler return to 172°F leaving the house? Do you circulate a lot of water w/o pulling any heat from it?

The IR meter seems a little fussy and it takes some monkeying with but I think my readings were decent. Not as good as in line metering, but it's a start.

This is why I will use an IR meter if nothing else is handy, but I'm not fond of them... My preference is for some sort of analog or digital meter attached properly anyplace I want to get regular readings... Probably the cheapest / easiest might be those "frothing thermometers" that they sell on E-Bay for fairly short money, including I think sometimes in lots of several - tape one to each point of interest, and wrap the probe in a bunch of insulation - should give you a more reliable and accurate reading w/o futzing around with the IR gun...

Gooserider

 

[ken999]

Weird as in 10 degrees difference from fittings to adjoining pipe sections. Got me...

1 1/4" pex from the wall to an existing Hoval combination wood/oil boiler w/ 37 gallon domestic tank integrated. 40' or so...(house is 34' long, t-pex comes in the house on the opposite end of the basement from the Hoval.) My OWB is plumbed directly into the Hoval.

I've taken some more readings tonight and I get 178 supply temps at the foundation wall when the OWB bottoms out at 180. As far as I can tell I get 2-3 degrees drop from the OWB to the house IF the controller temp is right on the OWB. Or IF the IR reading is correct...lol...anyways I get around 5 degrees drop right there at the foundation wall...1 1/4" in, 1 1/4" out. 178 in from the OWB, 173 back out to the OWB.

Now, checking the 3/4" pex lines off the Hoval gets me 176-178 out, 152 or so back into the Hoval. The FF loop is fed by a 007 Taco. I'm not sure the total length of this loop but I could measure it if it will help. This is the 48' of baseboard on the FF that is in question. 25 or so degrees drop sounds to me like I'm stripping the heat off pretty good in this loop.

I need to insulate the lines in the back of the OWB and I COULD try to insulate the 1 1/4" pex supply in the basement to tweak out the last degree or two, but it sounds like I'm not all that far off. I'd like to increase the FF baseboard to 60' or so to strip some more heat off in cold cold conditions (-20f).

Bumping the OWB to 190 in a cold snap would likely help a bit too.

 

[Gooserider]

Weird as in 10 degrees difference from fittings to adjoining pipe sections. Got me...

OK, this is one of the limitations of an IR thermometer - it will read differently depending on the nature of the surface you are shooting, and it's responding differently to the PEX and the fittings. Some folks suggest putting strips of black electrical tape on the points you are measuring, and shooting the tape - it's supposed to give more consistent readings since the surfaces stay the same... Another thing that can make a big difference is the distance between the object and the gun - the "spot" that it measures is an angle, so the farther you are from the target, the bigger the spot and vice versa - on a relatively small and round object it can make a difference if you are far enough away to pick up the background as well as the thing being measured...

1 1/4" pex from the wall to an existing Hoval combination wood/oil boiler w/ 37 gallon domestic tank integrated. 40' or so...(house is 34' long, t-pex comes in the house on the opposite end of the basement from the Hoval.) My OWB is plumbed directly into the Hoval.

OK, so it sounds like what you are doing is a sort of hydraulic separator / Primary-Secondary variation where you have a primary loop going from the OWB to the Hoval and back, and then pull off the baseboards as a secondary loop - The layout makes more sense to me, though the temp numbers still don't, quite...

I've taken some more readings tonight and I get 178 supply temps at the foundation wall when the OWB bottoms out at 180. As far as I can tell I get 2-3 degrees drop from the OWB to the house IF the controller temp is right on the OWB. Or IF the IR reading is correct...lol...anyways I get around 5 degrees drop right there at the foundation wall...1 1/4" in, 1 1/4" out. 178 in from the OWB, 173 back out to the OWB.

Assuming that is right, figure 5°F drop for the round trip - acceptable but not great...

Now what I'm confused by, is it seems like you are hardly getting any drop across the Hoval - your prior seemed to say you were dropping a couple degrees running across the basement and back with the uninsulated PEX (not inherently bad since it's heat that you are finding useful) This suggests that either the numbers are wrong, or you are pushing so much water through the primary loop that the 152°F return from the secondary loop isn't mixing down the primary temp significantly... If so, it would suggest that you are way over-pumping the primary - ideally your secondary drop should be pulling most of the heat available in the primary - otherwise you are just wasting a lot of energy pushing BTU's around the primary loop...

Now, checking the 3/4" pex lines off the Hoval gets me 176-178 out, 152 or so back into the Hoval. The FF loop is fed by a 007 Taco. I'm not sure the total length of this loop but I could measure it if it will help. This is the 48' of baseboard on the FF that is in question. 25 or so degrees drop sounds to me like I'm stripping the heat off pretty good in this loop.

I would agree, it sounds to me like the the baseboard loop is doing about what it should... But if you are having trouble keeping the house warm on design day, this sounds like the problem area, where you don't have enough emitter to supply the needed BTU's.

I need to insulate the lines in the back of the OWB and I COULD try to insulate the 1 1/4" pex supply in the basement to tweak out the last degree or two, but it sounds like I'm not all that far off. I'd like to increase the FF baseboard to 60' or so to strip some more heat off in cold cold conditions (-20f).

Given the existing drop I would probably say not to add more BB to that loop, as I don't think you have the temperature to support it... Instead I would say to look at improving your insulation / weather sealing in order to cut down on the demand side, or look at adding additional loops of emission in parallel to the existing one... On general principles, I would say to consider lower temp emitters like retrofitting underfloor radiant, or panel radiators rather than BB, but that is a side issue.

Insulating the primary loop lines will no doubt help a small amount by reducing your drops there, but that doesn't seem to be your problem, the main issue seems to be a lack of emitter area... The reason it now seems inadequate is that with the old system, you had the heat losses from the Hoval warming your basement, and helping the BB - but you've now moved those losses outside with the OWB...

Bumping the OWB to 190 in a cold snap would likely help a bit too.[/quote]

Agreed, just because it would push the BB water temps up that much more, but again it doesn't seem to be the main issue...

 

[ken999]

Thanks GR...That's kinda the picture my heating system is starting to paint in my little pea brain.

It certainly is nice (and appreciated) to hear your thoughts on the matter. What you are telling me makes alot of sense.

I was chatting with my brother over the phone last night about my dilema, and he spit out your suggestion of adding another loop. He doesn't know any more about hydronics than I do, but it appears he nailed it while I was busy not seeing the forest through the trees....lol...he will get a chuckle out of that I'm sure.

I was happy to find that I'm hitting the FF baseboard with some pretty good numbers and am not loosing a ton of BTU's before they get to the 'dance' so to speak. I am on a hillside and have a fair amount of water creeping down the ledgerock underground, so I took a former co-workers advice and underdrained the T-pex with #2 stone and pipe, daylighting it out in the yard. Then I placed the T-pex on top of the fabric wrapping the pipe/stone and backfilled with sand 2" or so above the T-pex, then covered the sand with a layer of 2" rigid foam followed by another foot of sand.

It seems that these extra precautions are paying off in terms of decent supply temps with minimal heat loss. The rest I can work on...

I guess the question now is..."what first?"...??...Would a slower pump allow for more heat dump in the primary loop from the OWB? IF I can pull more heat from the primary, would it reduce my consumption at all?

I'd like to dump more heat in the basement via my existing Modine and let it 'soak' up through the house, but I'm afraid I'd loose too much of it given inadequate sill plate insulation and leaky doors (Bilco and one leading up into the attached unheated garage). Not alot of bang for the buck despite the already in place emitter. Adding a some radiant pex would likely focus the heat more towards my target area, the FF. Now mind you, we aren't freezing by any means with the first floor temps hovering in the low to mid 70's...I was just miffed by not being able to push the temps higher with the new system in place.

Given time and money, I really want to spray foam the sill (and alot of other places...) to cut down on the demand, but that will likely wait until I get some other areas of the house ready to be foamed, then I can get it done all in one shot.

 

[ken999]

I guess I should add that somewhere down the line, another year or three, I'll be adding a loop for the attached garage when I get around to ripping-tearing-referbing said garage. Maybe I should shelf the 014 and go with a slower pump until then?? Course, by then my house should be in better shape insulation wise and my overall demand might not be any more then than it is now....??....


...lol...

what to do, what to do??

 

[MNBobcat]

I guess I should add that somewhere down the line, another year or three, I'll be adding a loop for the attached garage when I get around to ripping-tearing-referbing said garage. Maybe I should shelf the 014 and go with a slower pump until then?? Course, by then my house should be in better shape insulation wise and my overall demand might not be any more then than it is now....??....


...lol...

what to do, what to do??

Hi Ken,

You must have missed my earlier reply to you. Get the 3-speed Grundfos 26-99 pump that I told you about earlier. Menards sells them. You can run the pump on slow now and turn it up higher later if you add another loop and need a higher GPM. It makes absolutely no sense to run the taco pump and be stuck with one speed. Most of us here are not hydronic engineers. The odds of us getting everything right with our system design is slim. You want the ability to try different pump speeds and see what works best. If you under-calculated your GPM needs its a lot easier to flip the speed adjustment switch than it is to go buy another pump and install it.

 

[Gooserider]

Thanks GR...That's kinda the picture my heating system is starting to paint in my little pea brain.

It certainly is nice (and appreciated) to hear your thoughts on the matter. What you are telling me makes alot of sense.

I was chatting with my brother over the phone last night about my dilema, and he spit out your suggestion of adding another loop. He doesn't know any more about hydronics than I do, but it appears he nailed it while I was busy not seeing the forest through the trees....lol...he will get a chuckle out of that I'm sure.

I was happy to find that I'm hitting the FF baseboard with some pretty good numbers and am not loosing a ton of BTU's before they get to the 'dance' so to speak. I am on a hillside and have a fair amount of water creeping down the ledgerock underground, so I took a former co-workers advice and underdrained the T-pex with #2 stone and pipe, daylighting it out in the yard. Then I placed the T-pex on top of the fabric wrapping the pipe/stone and backfilled with sand 2" or so above the T-pex, then covered the sand with a layer of 2" rigid foam followed by another foot of sand.

Sounds like you did the T-pex as right as it can be done, and aren't having any serious problem there... You are definitely getting the BTU's to where they should be going, but you need to work on kicking them out of the pipe when they do...

It seems that these extra precautions are paying off in terms of decent supply temps with minimal heat loss. The rest I can work on...

Agreed...

I guess the question now is..."what first?"...??...Would a slower pump allow for more heat dump in the primary loop from the OWB? IF I can pull more heat from the primary, would it reduce my consumption at all?

Well it looks like the current pump is pushing a lot more BTU's around the loop than you need. Not sure how that impacts your wood consumption, but it is certainly wasting electric power to drive the over-sized pump A slower pump would move fewer gpms to the house at about the same temperature, and draw fewer KWh of electric doing it... Because the flow rate would be slower, and the total number of BTU's circulating would be less, you will likely see a greater temperature drop in the lines, but that isn't really a problem. You presumably would be best off if the temperature leaving the Hoval on the way back to the OWB was only a couple of degrees higher than the temp returning to the Hoval from the BB loop - that way you are effectively using all the usable BTU's that the OWB is sending you, with the remainder staying in the OWB, which I would expect to idle more since it isn't having to deliver as much heat. What I'm not sure about is how much impact this would actually have since you aren't actually "using" those extra BTU's that are running around the primary loop...

The multi-speed pump suggested might be a reasonable approach, as it would allow you to play w/ different speeds to see just which one works best - the other option might be to look at one of the variable speed temperature adjusting pumps, though some of the posts in other threads suggest that there may be issues with those at present. The good side of this whole situation is that it tells you that you have plenty of capacity to spare for when you do add those additional loops to warm the basement and garage...

I'd like to dump more heat in the basement via my existing Modine and let it 'soak' up through the house, but I'm afraid I'd loose too much of it given inadequate sill plate insulation and leaky doors (Bilco and one leading up into the attached unheated garage). Not alot of bang for the buck despite the already in place emitter. Adding a some radiant pex would likely focus the heat more towards my target area, the FF. Now mind you, we aren't freezing by any means with the first floor temps hovering in the low to mid 70's...I was just miffed by not being able to push the temps higher with the new system in place.

Given that it sounds like you have a lot of air leaks, I agree that doing some radiant PEX as the extra loop would probably be more effective than the Modine... The radiant floor would also have the advantage that you could drive it using the cooler water returning from the BB loop, and get additional BTU's out of the same water, without needing to increase the flow to the house loads. If your basement ceiling is unfinished, it would seem like a relatively simple and easy thing to do... Normally they say to cover and insulate the PEX to drive the heat up, but it seems like this might be a time not to do that - at least for now, since it seems you want heat going both up and down...

Given time and money, I really want to spray foam the sill (and alot of other places...) to cut down on the demand, but that will likely wait until I get some other areas of the house ready to be foamed, then I can get it done all in one shot.

That makes sense, given that the cost for any of these services includes a lot of travel and setup time...

Gooserider

 

[ken999]

MNBobcat- I didn't miss your earlier reply. A Grunsfos will likely be in my future. The guy who did my install and I had talked about one, we were just waiting to see how the 014 performed.

GR- I'll fiddle some more tonight with the IR gun. I want to try all zones calling for heat, worst case scenario, to see what kind of drop I get in the primary loop. This should give me some kind of indication of what I can get away with in the future. I don't expect my overall demand to grow when I add the garage loop, as I should be better insulated by then. If I don't get too much drop in the primary with all zones calling for heat, I will try a pump with lower capacity.

Yes, my basement is unfinished. The radiant add-on would be fairly simple. Are you suggesting that I just add it on the end of the FF baseboard loop, same 007 pump?

I actually was going to have the T-pex spray foamed, but the guy came to spray and had trouble with his equipment and only got 10' from the house before it quit. I couldn't wait the week or two for him to get things fixed, so I went to plan B and used rigid foam over the top of the T-pex.

After seeing some pic's of guys spray foaming regular pex (like Jim K in PA), I'll likely never go the T-pex route again. Eventually, I'll be adding a detached garage (right after hitting the lottery...) and will need a second primary loop off the OWB.

 

[Gooserider]

MNBobcat- I didn't miss your earlier reply. A Grunsfos will likely be in my future. The guy who did my install and I had talked about one, we were just waiting to see how the 014 performed.

GR- I'll fiddle some more tonight with the IR gun. I want to try all zones calling for heat, worst case scenario, to see what kind of drop I get in the primary loop. This should give me some kind of indication of what I can get away with in the future. I don't expect my overall demand to grow when I add the garage loop, as I should be better insulated by then. If I don't get too much drop in the primary with all zones calling for heat, I will try a pump with lower capacity.

Sounds like a good idea - as it is important to make sure you have adequate heat during a "worst case" scenario.

Yes, my basement is unfinished. The radiant add-on would be fairly simple. Are you suggesting that I just add it on the end of the FF baseboard loop, same 007 pump?

You could, but I would probably do it as a second loop with a mix valve, as even 150°F is on the hot side for a floor loop - and floor loops tend to work better with a fairly steady supply of warmish water, rather than an on-off supply of hot water. I would want the supply side of the floor loop to be a tie in to the Hoval right at the point where the BB loop comes in, and the return side to either a different port on the Hoval, or possibly a tee into the return side of the primary loop PEX so that if the BB loop is running the floor loop can use it's low temperature return, or pull full temperature from the primary loop if it isn't... My thought is that your ideal setup would be to have the floor loop supply most of your heat demand during normal conditions, with the BB loop just kicking in under unusually high loads... This would give maximum advantage to the lower operating temps and better performance / comfort of infloor radiant, while keeping the BB for it's faster response when needed.

I actually was going to have the T-pex spray foamed, but the guy came to spray and had trouble with his equipment and only got 10' from the house before it quit. I couldn't wait the week or two for him to get things fixed, so I went to plan B and used rigid foam over the top of the T-pex.

After seeing some pic's of guys spray foaming regular pex (like Jim K in PA), I'll likely never go the T-pex route again. Eventually, I'll be adding a detached garage (right after hitting the lottery...) and will need a second primary loop off the OWB.

I agree, I think that if one is doing outside lines (I want to put my boiler inside, so it won't be an issue I have to deal with) the foam on regular PEX is the best way to go...

Gooserider

 

[ken999]

I switched off my zone 4 priority (domestic hot water) on the control board and could get 15-18 deg. drop in the primary loop tonight with all four zones calling for heat. This also knocked the boiler down to 178, which I've never seen before. It may have dipped lower before I thought to look out the window at it when I came back upstairs after checking the temps. Usually it will kick on at 180 and not dip below. Apparently I can pull the heat off the primary loop pretty good if need be. I'm going to leave the priority off for a few days to see how things act.

 

[ken999]

We seem to have plenty of hot water still with the priority switch off. I just bumped all the t-stats up to call for heat and went to check my primary drop downstairs....had 19 deg. differential without the domestic zone calling for heat.

At this point I'd say that a variable speed pump wiith the high setting being close to the 0014 would be be a good idea, especially since I was planning to try the boiler in the summer for domestic.