Heating issues and circulator pump size

dcf1999

I'll try to make this as short as possible... My house has a radiant heat system with 3 zones. Zone 1 is the garage, 2 is the entry & small bathroom, and zone 3 is 17' x 11' room. I'm not sure who designed and / or installed the system. The garage and entry zones work awesome! The 17 x 11 room, not so much. Last winter the pump would run 24 hours a day and could barely maintain 60 degrees. We ran a space heater to help keep it warmer. We would like like to keep it at 68 - 70. Entry is concrete slab with tile (as is garage). The other room is over crawl space with wood sub floor and carpet. This year I went into crawl to have a look and noticed the tubing is stabled to the sides of the joists (See attached pics). Couple weeks ago I finished pulling them all down and stapling them (using aluminum plates) to the underside of subfloor. Tested it out last week when the room was at 65 degrees. After about 5 hours, it felt (maybe my imagination) as if the floor was warm but temp actually went down to 64 degrees with system running.

I like to learn about this stuff so I've been doing a lot of research. I calculated the heating load needed for that room at 13,059 BtuH. The water should have a 1.3 GPM flow and I have 300' of PEX which equates to about 20' of head (using manufactures pressure drop chart with 30% glycol mix). Right now I have a Taco 007 pump but, according to specs, only will pump up to 11' of head. Do I need a more powerful pump? Like the Taco 0011? Before I spend $250 on a pump, I want to make sure that will help my issue with heat. I know the carpet doesn't help, and if it's not going to do much to upgrade pump, I'll just have to live with it. The difference between supply and return temp is 15 to 30 degrees... those temps are measured off the inlet and outlet posts of water heater (system uses a water heater instead of a boiler) so there maybe some error there.

Some other general questions.

How do I know what GPM is flowing through the tube? According to my calculations (well Taco software calculations), I need to have 1.3 GPM running through, do I just regulate that using the valves before or after the pump?

I have anti-freeze in the lines... Do I really need that? Can I use straight water? I live in Northern IL, if I loose power, how long till stuff starts freezing up? I'm rarely gone for longer that 3 days in the winter (and that maybe 2 times a year) and do have a backup generator if power goes out and I'm home.

Thank You,

Dave

njtommy

Looking at the numbers you posted you are defiantly undersized for your pump. You may also find the Taco 009 would work.

I can't believe they tried to do radaint floors like that.

Depending on how handy you are you could add a normal radaint manifold to adjust flow or look for a circuit setter to slow the water down.
You could also close down the ball valve outlet side of the pump for the zone. Till you get a better temperature split of around 10 degrees (assuming but could be higher) Did the taco software tell you what your split should be?

4Johnpipe

That's a problem. Suspended tube needs considerably higher water temps than emission plates or track / embedded tubing. Is that bubble wrap? I hope it is at least well insulated. Yes 009 is an option.

Gordy

The best improvement was installing the tubing with plates to the subfloor. You also need to insulate the joist bays well with extra attention to the perimeter rim joist areas.

Did you use extruded plates?

Bubble foil does not count as insulation in my book.

Is the carpet and padding high r value?

Lastly you may not be getting hot enough water from a water heater for a poorly insulated suspended tube method with carpeted floors over a crawl space in northern Illinois. 3 strikes .method, workmanship,and climate.

You made one big change by switching to plated under floor.

Zman

You you have already received a lot of good feedback.
Here's my 2 cents:
I have never seen a 17x11 room that needs that many BTU's, double check the math.
Your circ could stand to be a be a bit bigger, but I don't think that is the problem.
One problem that is very common with your type of setup is the high mass slabs steal all the BTU's from the system, especially when they are cold. This leaves the underfloor heat starving.
What are your actual water temps? How many BTU's does the water heater put out. Does the underfloor zone work OK when it is the only zone calling?
A digital dual temp thermocoupler with clamp on sensors make easy work of trouble shooting the problem.

dcf1999

Ok... That's everyone for your help. I'll try to answer everyone's questions.

Taco software said split should be 10 degrees. (I assume split you mean diff between supply and return?)

I used omega type plates. The extruded plates were way out of my budget. Just had a baby and wife is now stay at home so I can't spend like I used to. The bay's are insulated with R-38 insulation. Not sure R value of carpet but it's a thicker nap so I assume it's higher.

The 17 x 11 room (we call it the sunroom) has a lot of windows so maybe that's why the btu's are higher? There are 2 large windows on west side where its pretty windy in winter. Taco software takes in accout location so maybe it's adjusting for temps, wind speed and windows? I'll redo the math though. The water temp leaving WH I believe is between 120 - 130. I'll double check that tomorrow. The garage is 24 x 24 so that could be robbing it. BTU of WH is 47,000.

Tested zone by itself yesterday. I felt warm spots where the plates are stapled up but temp never rose. However, room temp was at 73 already and only ran it for a few hours so I assume that's why. Temps are supposed to drop to 40's at night this week so I'll test that zone by itself when it gets colder.

I need to buy a clamp on therm for my multimeter. That's going to be my next tool purchase. I've had couple occasions where it could come in handy.

Seems like most people agree about upgrading pump. I'll upgrade it to a 009. I'm also going to buy a flow meter and test each zone to see what the pump output is and adjust accordingly. Will also measure the temp diff between supply and return on each zone.

Garage slab also uses a 007 pump, has lager dia tube and I assume has longer runs. (Don't know actual run length cuz foot markings on tube are hidden). Garage heats up fine though. But maybe the head is too high and flow too slow (with the 007 pump) in garage zone causing problems with sunroom zone?

My WH looks to be pretty rusty (on inside by pilot light) and I think has a lot of sediment. I tried to drain a little out when doing repairs and only about 3 gal came out of bottom drain valve before valve stopped flowing. I don't know if antifreeze mix has been tested and/or replaced anytime during system life. I'm going to test PH in the system this week. What's everyones opinion on glycol? Add or use plain water. I know plain water is better for heat transfer but I also don't want a situation if electric goes out and I'm out of town.

Thanks again everyone.

Dave

hot_rod

I'd guess the carpet and pad are limiting the output considerably, lack of under floor insulation also.

Generally 140F and higher for tube under plywood, carpet and pad.

I agree that the WH may not have enough output or go over 120F on the control. So lack of BTU and adequate temperature, perhaps.

dcf1999

How much insulation should I have between the joist bays? The R-34 is pretty think. Not shouts how much more I can add wi though compressing it.

Also checked output temp and it's at 140

hot_rod

How deep are the joists? No sense in jamming in more that the space can accommodate, you actually decrease the value as you compress.

With transfer plates it's fine to push it against them, no air gap needed.

dcf1999

I think 2x8 or 2x10. Never measured them but the insulation thickness was a perfect fit. I installed a reflective insulation membrane (can't rmemeber the name. Was there originally) on against plates then Installed the R-38.

I got a digital duel thermometer coming tomorrow so I can measure the difference between supply and return and aim for 10 degree difference. Also have a flow meter coming so I cam adjust the flow on each zone.

I have a feeling the WH BTU rating is too low as well. I don't have the money this year, but next year plan on installing boiler.

Supposed to be 28 friday night so it might be a good test to see if it maintains temp

hot_rod

Reflective surfaces don't really add much. First then need some air space to work, if they touch the plate they conduct some heat away. Also they need to be and stay fairly shiny to work, which rarely happens.

I don't think that will cause you much grief at this point, you have bigger fish to fry..

See how it works next cold snap.

To troubleshoot further you would need to determine the heat load, then calculate all the r-value above the tube and plate and see if you have enough emitter and temperature to cover the heat load. Sunrooms can be a tough load.

Carpet, pad and 3/4 subfloor comes out to about R2.8.
Radiant friendly surfaces may be needed to get you over the hump.

You have around 187 square feet of heat emitter, deduct any furnishings that go down to the floor like couches and built-ins.

If the burner and inside of the WH are rusty, that may indicate it is in extended condensing mode, running too cold. Another sign that you don't have enough horsepower.

Check the condition of the flue piping also, it can be compromised by extended cold operations if it is metal venting.

A CO detector might be a good investment, if you plan on running that WH. Corroded burners and HXers are never a good sign.

dcf1999

Thanks for your and everyone good advice. Hooked up a duel temp tool and supply is 130 and return is 110. Supposed to be 25 tomorrow night so we'll see how she performs.

Next year I'm going to invest in a boiler. Menards has a tankless one (it's listed tankless boiler for hydronic heating rated at like 170k BtuH). I think using a boiler, I can bump up the supply temp as well. I'll probably have a prof HVAC guy come over to install that unless I know for sure I can do it. I mean I know I can physically install it, I'm more worried about it being compadible with the systems and what, if any, mods I'd have to make. Although I'm not the the type to turn down a challenge and opertunity to learn.

Nobody has yet answered my question about adding glycol to the water? If it's a good idea or not, or what the industry standard is?

I see hotrods point about the foil insulation sitting against heat plates but at this point it's too late. I'm not tearing down all insulation again. I didn't install it too tight against them anyways.

This year I'm going to start by installing a taco 009 or 0011 in that zone

dcf1999

Oh... And I have a CO near that location. The room with all the equipment is located in garage. I have a CO detected in the entry hallway to the garage. Before the baby I made sure I had one in every floor of house.

SWEI

dcf1999 said:

Next year I'm going to invest in a boiler. Menards has a tankless one (it's listed tankless boiler for hydronic heating rated at like 170k BtuH). I think using a boiler, I can bump up the supply temp as well.

Most of us would probably not consider that a very good investment. You need to start with a heat loss calculation. How big is your house?

njtommy

I would leave the glycol in the system better safe then sorry. The % of your mixture (water and Glycol) is unknown so it's hard to say what temperature your good down to. A refractometer would be helpful.

Gordy

With the garage being in the system keep the glycol, but it's concentration needs to be maintained/checked. The only way to get the rest of the house off glycol mix is to use a heat exchanger for the garage zone.

Is the water heater turned all the way up? 150 ish.

Something to try and get you by is to keep garage zone off, or turned way down during colder snaps when problem zone won't keep temp. Like Carl says its soaking up a lot of btus. You have glycol so freezing should not be an issue if concentration is up to snuff.

Zman

The temp gauge is a great trouble shooting tool. Be sure to note how it performs with slabs calling for heat.

Gordy

Like Kurt says stay away from the menards stuff. If you find you can't resist I would recommend the westing house mod/con they are now carrying Its a spin off of the HTP line.

dcf1999

I'm going to check the concentration and PH of the glycol. Will a standard automotive coolant tester work with glycol or do I need a special one?

I'll stay away from the boiler for now and just get the highest btu water heater I can find but I'll look into tht more next year. System is staying same (except for pump) this year.

The garage zone is the zone tht runs the least out of all of them. I keep it at 55. For **** and grins, I cranked it up to 70 one day and it heated up relatively fast. Garage is insulated very well.

SWEI: I did the heat loss calc. I'm going to re-do it though to make sure math is good. House is large and is all forced air except for 3 rooms: entry, garage, sunroom. Sunroom is 17x 11 and the one with the issues.

It's going to get cold tonight and system will run. I'll do a supply and return temp test in the AM Amd return results.

Btw... This morning, wife and I both could "feel" the floor was warmer after I installed plates. So that makes me feel better.

Is it normal for a zone to run 18-24 hours of the day to maintain temp? Or should it run for a few hours a day only? Maybe Im over reacting.

Jamie Hall

On the glycol. Keep it, or renew it. You need it for when (not if) the power goes off. You can test the concentration with an automotive tester, if it's ethylene glycol. The results won't be quite right if it's propylene, but they won't be that far off.

And an ideally designed zone does run 24/7; with the modern mod/con type systems the outdoor reset simply adjusts the water temperature to maintain the floor temperature. For any system it should run that way ideally at design temperatures... but they often don't.

dcf1999

Ok. Got down to about 30 last night. Woke up this morning and room was at 68. Thermostat is set at 70. The sunroom was the only zone running at the time. My electronic dual thermometer reading was 120 supply and 119 return... Gauges on WH show 130 supply and 100 return. The WH gauges are right at inlet and outlet Of WH. So I don't know which one is off. I'm going to have to test the electronic thermometer to see how accurate it is.

I'm buying a new return temp gauge for WH as it's as old as system and maybe its off.

I think my next steps is: 009 pump and invest in a new, more powerful WH. I'm having trouble finding one that's over 50,000 btu. I may have to special order one. I'm also on LP so that may be a reason as well as I believe LP has less BTU's than NG. Also going to install low e storms on the west exposure windows to help with insulation.

One of the remodel projects in the next few years is to install tile floor... When that happens I'm abandoning loop under subfloor and installing a new loop above the subfloor in Chaneled plywood then a layer of mortar with cement board and tile. It will raise my floor at least an inch but I bet if will work a lot better being above the wood and heating up cement board and tile.

For now though, I suppose it is what if is. Real test will be when it drops into the single digits.

dcf1999

Hopefully I'm not wasting everyone's time. People here are so helpful and willing to give advice instead of saying "hire a professional". I find other forums I visit, that's the first comment. I'm a pretty big DIYer and love to learn and try to do everything myself but also know when I'm over my head and when it's time to hire someone out. I do not like to half **** things so I ask a lot of questions. I want to thank everyone for their help and advice!

Dave.

Zman

You test is definitely indicating low flow. The water heater gauges are puzzling. Does the digital thermometer agree with the physical gauges?
Another possibility is that you are getting ghost flow though the slabs while the other zone is calling. Do the circs have check valves? What are the temps of those zones while the under floor zone is calling?

dcf1999

Last year it took me a month of head scratching to finally figure out I had ghost flow. When sunroom zone was on it was ok till I turned on entry zone... When both zones were on, sunroom zone stopped flowing unless all three zones were on. Turns out entry zone return would back flow through garage zone (when garage zone not on) and re supply entry zone bypassing sunroom zone (if that makes sense). Figured it out when I installed a spair gunfos pump (with check) on the garage zone and that fixed the proble.

Anyways... I installed check valves on all zones this year (isolator valves with check valves built in) and other zone pipes feel cold when zone is running. So there should be no ghost flow. No digital gauges and physical ones don't agree.

When system isn't running supply and return temp on electronic therm is matched +/- 1 degree. When system starts up, and zone starts heating, physical gauge on supply is matched to electronic supply temp. After awhile (and water heater kicks in and temp rises) physical gauge reads higher than electronic gauge by about 20 degrees. Plus, when zone has been on for 4+ hours, electronic tool says supply and return are same temp (119 degrees) however, you can def feel the pipes and they are not the same. Supply almost burns your hand (can only hold on to copper pipe for a couple seconds) while return you can hold on to and its hot, but not burning hot.

Didn't test those zones yet. I can do that tonight.

I'm using k-type thermocouples... Just the plane ones with 2 wires and a little ball at the end. I tape them to the pipes using electrical tape. maybe the thermocouples are junk and I need to invest in field piece or fluke brand pipe clamp type couplers. Golly, if my wife knew how much I spend on tools and how much I complain on her buying purses and stuff... But I like my name brand tools (snap on, field piece, Klein, etc...)

dcf1999

I dunno, the whole temp thing puzzles me now that I think about it. Everything matches until hot water is flowing, then nothing matches up so something is reading wrong and I need to figure out which one is out of wack. Maybe I'll take a sample of water from system and measure that directly with my fieldpiece prope therm and see what that says.

If in fact my electronic temp gauge is correct, and my supply is maxed out at 119, then I would think it's not hot enough as I need probably 130 - 140 degree temps for that zone. Something tells me those gauges you buy maybe are not that accurate? Plus there is no way to calibrate them

RobG

If you are using an IR thermometer you need to put a piece of matte tape on the pipes to get a relatively accurate reading.