Radiant heat questions

jhilly

I have my system up and running. 125 degrees inlet and 125 return. Mixing valve wide open been circulation for 3 days with pump right after water heater and circulation pump on board. Constant hot glycol can't get my room temp to be over 62 at floor. One layer of reflective foil 4 inches from tubes stapled to underside of subfloor. Another layer of foil flush with floor truss. 2" reflective foam board as final cover. After 3 days shouldn't I have 80-90 degree floor?

Ironman

How how about posting some pics?

Alan (California Radiant) Forbes

Supply and return at the same temperature? That means there's no heat transfer happening. I'd say that your pump wasn't working or more likely, your system is air bound and you have no water movement through your system.

Is this a new installation?

jhilly

New install. I swear I've purged loop and then system. Return line was like 60 inlet was 125 running only circulator on board when mix valve moved to 3.

Ironman said:

How how about posting some pics?

I'll post pics tonight.

hcpatel78

I read somewhere staple up install without transfer plate need higher SWT around 140+.

jhilly

hcpatel78 said:

I Read somewhere staple up install without transfer plate need higher SWT around 140+.

My water heater is floored to 150 on thermostat but I'm only getting 125. 4500 watt dual element brand new filled 100% glycol

Ironman

An electric water heater can only produce 15,300 btus. Unless you have a very small/tight house, that’s not gonna do the job.

jhilly

Ironman said:

An electric water heater can only produce 15,300 btus. Unless you have a very small/tight house, that’s not gonna do the job.

600 total square feet , tight as all get out. Right now one loop at 225 feet of hose being used....enough? My WH is listed at 40000 btu

Jamie Hall

Two comments. First, if your inlet and outlet temperatures are the same, there's no heat going into the floor. You need to find out why. No circulation in the floor loop? You should be getting around 1.5 to 2 gpm.

Second, an electric water heater is probably the most expensive possible heat source, even if it did have the capacity -- and at a maximum of 15K BTUh, it might (actually, it probably is close to what that floor area can absorb). But without knowing the actual heat loss of the space, one can't say.

JUGHNE

Dual element 4500 watt implies that there are two 4500watt elements in the tank.
The control design is such that only one is energized at a time.
If the control system is hacked such that both elements are on together then the standard 30 amp #10 wire size will be overloaded. Both elements on will draw a nearly constant 40 amps.

You have 100% glycol in the system, no mix?

jhilly

JUGHNE said:

Dual element 4500 watt implies that there are two 4500watt elements in the tank.
The control design is such that only one is energized at a time.
If the control system is hacked such that both elements are on together then the standard 30 amp #10 wire size will be overloaded. Both elements on will draw a nearly constant 40 amps.

You have 100% glycol in the system, no mix?

Correct dual 4500 elements top and bottom. Yes 100%glycol. So my 40000 btuwill only give me 15000 btu why? 638 square foot tiny home. Only trying to heat 250 square feet right now

Ironman

jhilly said:

Ironman said:

An electric water heater can only produce 15,300 btus. Unless you have a very small/tight house, that’s not gonna do the job.

4500 watts X 3.413 = 15,358 btus. That's physics and it doesn't change. As mentioned, only one element can operate at a time. The top one first heats the top 1/3rd of the tank, then it allows the bottom element to heat the remaining 2/3rds of the tank.

As Jamie mentioned, if the supply and return temps are the same, then you're not getting flow through the floor.

How about posting some pics? I suspect it may not be piped correctly.

Jamie Hall

jhilly said:

JUGHNE said:

Dual element 4500 watt implies that there are two 4500watt elements in the tank.
The control design is such that only one is energized at a time.
If the control system is hacked such that both elements are on together then the standard 30 amp #10 wire size will be overloaded. Both elements on will draw a nearly constant 40 amps.

You have 100% glycol in the system, no mix?

Correct dual 4500 elements top and bottom. Yes 100%glycol. So my 40000 btuwill only give me 15000 btu why? 638 square foot tiny home. Only trying to heat 250 square feet right now

100% glycol? It should be around 30% glycol -- assuming you need glycol at all, which seems unlikely.

And yes, your 4560 watt water heater has a maximum output of 15K BTUh. That's it, that's all. For pure water. That's the way they are wired. I wouldn't care to guess at the output for 100% glycol, but I'm going to guess at considerably less -- and the elements won't last long, since they will overheat due to the poor heat transfer properties of glycol.

jhilly

Used all glycol live in northern Michigan lose power often. Don't want lines to freeze.

Jamie Hall

jhilly said:

Used all glycol live in northern Michigan lose power often. Don't want lines to freeze.

The freeze point of 30% is 7 Fahrenheit; the freeze point of 60% is -55. Which should be adequate... even in northern Michigan...

Ironman

If you're using 100% glycol, the viscosity may be too high for the circulator to move it. Most pump manufacturers say no more than 50%.

JUGHNE

Also, what do you have for a pressure relief valve?
If you are relying on the relief valve that came with the electric water heater, it will open at 125-150 PSI and/or water temp of 210 degrees.
Both parameters are beyond any heating tubing, pumps or mixing valve safe operating limits.

Most hot water boilers have a 30 PSI pressure relief valve installed.
What pressure do you see at the tank?

jhilly

https://photos.app.goo.gl/BbF9JcrW79KjZHGp8

https://photos.app.goo.gl/HfQfZQ6wEuCdmnzw5

Ironman

The Grundfos pump at the water heater is not necessary as well as being in the wrong place.

Get the glycol level below 50% and remove that pump and see if you get flow after purging.

Also: you need a 10/2 cable on a two pole 30 amp breaker feeding the water heater, not a 14/2 cable. You’re gonna have a fire the way it is.

jhilly

Ironman said:

The Grundfos pump at the water heater is not necessary as well as being in the wrong place.

Get the glycol level below 50% and remove that pump and see if you get flow after purging.

Also: you need a 10/2 cable on a two pole 30 amp breaker feeding the water heater, not a 14/2 cable. You’re gonna have a fire the way it is.

Will do. The 12/2 is for the pump. 10/2 wired to 2 ole 30 amp on water heater.

hot_rod

After the above corrections, try opening just one or two loops and see what delta you get.

One loop for 600 q ft?

600 total square feet , tight as all get out. Right now one loop at 225 feet of hose being used....enough? My WH is listed at 40000 btu

jhilly

hot_rod said:

After the above corrections, try opening just one or two loops and see what delta you get.

One loop for 600 q ft?

600 total square feet , tight as all get out. Right now one loop at 225 feet of hose being used....enough? My WH is listed at 40000 btu

3 total loops. Only running one 225 foot loop right now.

hot_rod

I think you have an air lock.

jhilly

50/50 mix now. 130 inlet 105 return? Better to me but not sure.

Ironman

Is the floor producing enough heat to maintain room temperature?

jhilly

Ironman said:

Is the floor producing enough heat to maintain room temperature?

Only been running since 10pm last night takes a day or so right?

GroundUp

You likely have an airlock at the circulator due to it being physically higher than the water level in the tank, I see this quite a bit. Your system is also piped wrong, the circulator you added does not need to be there and will fight the other two as well as the mixing valve operation. If it were mine, I'd remove that pump altogether and suck the supply water from the relief port on the side of the tank (below the surface of the fluid level) using a tee so the T&P can be reinstalled. As for the glycol, there is a common misconception here and I highly doubt that you have 100% concentration in the system. What did you pump in, exactly? For example, the Cryo-Tek -100 you can buy from Menards is only a 55% concentration out of the bucket. So while it's 100% Cryo-Tek -100, it's only 55% glycol. 100% propylene is like syrup and almost impossible to move with a circulator, so if that is in fact the case here, you definitely need to drain 2/3 of it and refill with water for a 30-35% mixture

motoguy128

Jamie Hall said:

Used all glycol live in northern Michigan lose power often. Don't want lines to freeze.

The freeze point of 30% is 7 Fahrenheit; the freeze point of 60% is -55. Which should be adequate... even in northern Michigan...

Also need to consider that burst point is even lower. Freeze point it where it stops pumping.  

30% is fine for everything but snow melt systems.  Those often need 50%. 

How did you purge the system?  

rick in Alaska

"How did you purge the system? "
That's what I want to know. I don't see how it can be properly done the way it is set up. My money is on the other comments; You have air in the loops.
Also, why is it that when I open the link to the pictures that are available, that I can't get back to the site? The back arrow just keeps refreshing the picture.
Rick

Jamie Hall

On the pictures -- that may be a browser quirk on your end, @rick in Alaska . Works fine for me (if a little frightening...)

jhilly

I have valves at the manifold for the loop.  I close everything else but that one loop. Fluid into my fill valve right before board after air eliminator.  Close return valve to WH, just after return purge valve.  Transfer pumping thru loop open loop valve, exits out return valve till no bubbles or bursts.  Close loop valve, then ball valve at manifold.   Fill circulation pumps out return valve.  Reopen valve to manifold. Transfer pump on everything open valve to return line to WH.  
Thanks a bunch guys I'm just a mailman trying to divert my mind. Bring a frontline worker I'm beat. It's been 9 months 10-12 hours 7 days a week due the the pandemic and everybody's new love the evil.....Amazon.  I've finally started to get Sunday off and 'm very appreciative of everyone and the help I'm asking for. This space is a jam room for my kids and dad.  If I ever get home early enough to jam!

jhilly

Got air again.  Floor got to 70 degrees.  I think I need to move the purge valve to just before the air eliminator and not where it is.

jhilly

Got floor temps of 72-74.  I'm going back and installing aluminum fins under sub flooring.  Did it in the bathroom area wider radiant dispersed and got 80+ degrees.  The test will be when we get in the teens and single digits to see if the water heater can keep up.  Thanks for the help guys!!!

jhilly

Fins installed, R30 installed foil barrier over R30.  135 out 100-105 back.  Can't get floor heat over 72 and 60-61 at 6 foot.  More btu?  175 square feet is all I'm heating.

Gman66

Have you confirmed if the water heater is, or isn't, heating all the time? If current is flowing all the time then the heat is going somewhere. More likely the tank is hitting set point and current stops flowing until next call for heat. If it is reaching set point and going off, why is there not 150 degree water to the floor/system? You have some thermostatic mixing valves - are those on fully hot? If they are DHW mixing valves they may not go over 130 degrees which is probably not hot enough for your staple up.

jhilly

I have heard the wh elements turn on and when I have moved my mixing valve to full open 6....I hear fluid moving out of wh.  Circulation pump is running constantly has never shut off since thermostat has never seen 68 where it's set.