Help with infloor heat

Kaos

Fixing this unfortunately won't change how much propane you use. If you get a modcon dialed in, you might get 5%-10% lower depending on how it is running now. Easy one is to get the outdoor sensor installed and configure a reset curve. The rest is getting the return water temp as low as possible to the unit. This means adjusting flow rates and supply temps.

If you want real fuel savings, don't run the snow melt and figure out where you are loosing heat in the house. Most places, a bit of air sealing goes a long way and will save you more than a perfectly dialed in boiler.

bjohnhy

I wouldn't risk trying to fix it now. If something goes south you may end up losing your functioning air furnace.

The only thing I would try this winter season, is to put swap in new mixing valve , maybe one that can dial up higher than 150F (American degrees), and make sure the flow check valve is on the cold side of the mixing valve. Preferably a mixing valve with cV greater than 3.5

Tom99

Hey Kaos I might get the outdoor sensor installed probably in the summer though. I think I only ran the garage floor once like 2 years ago and haven't used it since. Don't think I'm loosing much heat in the house as it's spray foam and I had a blower door test done, front door needed adjusting but that's it. I probably will ask you guys some more questions in regards to flow rates and supply temps once I make this repair. Also thanks everyone for the education!

Tom99

I respect your opinion bjohny! I have a good friend who is a plumber, so to be honest I will probably have him do the pipe work to eliminate me screwing it up lol

bjohnhy

bjohnhy

https://forum.heatinghelp.com/discussion/comment/1828087#Comment_1828087

How do you build a spacer? Do you just use two flange isolation valves with a nipple in between?

Tom99

I was just thinking two couplings and a piece of pipe no?

PC7060

https://forum.heatinghelp.com/discussion/comment/1828098#Comment_1828098

You can use mating pump flanges with pipe to between pump isolation valves if you want to limit piping changes.

I see your system is configured with System 638 PVCS venting; are you in Canada?

Tom99

Hey pc7060 yea I'm in Canada

GGross

Is your snowmelt portion working OK?

hot_rod

I would think a plumber could make that change in a few hours? Not too risky. If he uses press it will go quickly

I would leave the upper pump iso valve, get a 1" sweat flange and make an adapter piece to press couple into the tube below the second iso valve, which you remove.

I see in this pic there is not a valve on the return line into the close tees. Add a press valve there also.

Remove the top of that mix valve, pull the guts and clean and lube the o-rings and cartridge.

Kaos

https://forum.heatinghelp.com/discussion/comment/1828093#Comment_1828093

If the place is tight already, the easy energy savings are done.

What are your local energy costs? I'm in Canada as well and heat pump is 2x to 2.5x cheaper to run. Cold climate heat pumps easily run down to -25C.

Generally not worth replacing good equipment, but if your AC dies, swap it out for a cold climate heat pump. Keep the hydro coil and set that as Aux heat, so the only time it will run if the heat pump can't keep up. If your rates are similar to mine the Aux and heat pump should run together as even when cold, the operating cost of propane is higher.

As for getting the existing setup tweaked, post system temperatures once you have fixed the mix valve issues and installed the outdoor sensor. You can use a meat thermometer to measure the discharge air temperature after the hydro coil.

DCContrarian

This is what I made up for a similar situation where I had to take out a circulator:

Although if the flanges that are there are threaded you're probably better off unscrewing them and putting in a copper to threaded adapter. If you do pro-press you don't have to worry about getting the pipe completely dry. Same with PEX crimp. You could do Sharkbite but I'd only trust that to get through to the summer.

Tom99

Thanks for all the tips guys! To be honest my plumber buddy does not seem to worried about the repair he said 2 hours and few beers, he also did say he's going to use pro press. As for setting up the system once repaired he has no experience with that at all, so I'm definitely going to need help with that. Kaos my propane is costing me 0.61 per liter average fill on the tank is $900. Once the furnace kicks the bucket I will explore some options.

Kaos

.61/l burnt in a 90% boiler works out to about $0.10/kWh. My average electricity rate including delivery is around $0.14, so burning propane is cheaper than resistance but more expensive than a heat pump with a COP above 1.4. If you look at something like bellow, the COP is above 1.4 even at -25C. On yearly usage, I would guess it would about 1/2 the cost to heat.

https://mylinkdrive.com/viewPdf?srcUrl=http://s3.amazonaws.com/enter.mehvac.com/DAMRoot/Original/10007%5CM_SUBMITTAL_PAA-A24BA1_PUZ-HA24NHA1-R1_en_M1.pdf

Tom99

What province are you in Kaos?

Kaos

I'm in Ontario.

Tom99

Finally got the repair done! Just have to get a longer piece of bx. Thanks everyone for the help. As for flow rates whats a starting point for this

bjohnhy

Are you getting better flow rate with that change? Higher than the 0.15gpm you mentioned before?

In terms of flow rate, you can start at 0.5 to 1.0 gpm, but then dial each loop in for a delta 10 to 15 degrees F (after 2 hrs of run time ). I would favor closer to 10F delta, especially after ODR dialed in. I take it you don't have any of the design specs or know how long each loop is.

Tom99

Hey thanks for the reply. I've attached a pic of the current flow rates. No design specs or do I know how long each loop is. The basement is approx 1500sqft

Tom99

This is what I have coming into the manifold for temp

Tom99

And on the return

Tom99

Also yes flow got better with the change. I also notice if I close the mixing valve flow also improves but I just left it fully open as that's what the last mechanical guy had it set to

hot_rod

you can’t really close a mixing valve, as you turn the knob one side opens more as the other closes the same amount

Lack of flow is most often plugged strainers

Most valves have strainers on the hot and cold ports

Personally I would leave the strainers out. They are mainly for domestic water protection

IMG_9420.png

Tom99

Hey hot-rod both strainers have been cleaned so no luggage. I remember another poster mentioning a bigger mixing valve ?

hot_rod

that is probably a 3 Cv valve, so 5 loops at .6-.6 gpm if fine with that circ

Looks to me like the supply us 120 return just under 100?

Tom99

Isn't the supply the temp gauge on the manifold? Cause that one is reading just under 100f

bjohnhy

It looks like the boiler supply temp gauge states 120 and the mixed temp (supply to manifold) states 100

I don't see a return temp. When i was referring to a delta 10F supply vs return to help dial in the flow, I was referring to a mixed temp compared to the temp on the individual return loop coming right out of the concrete. There is not temp gauge there now.

Tom99

Thanks guys. I'm lost with all this, so what i got going on now is ok? I would just hire someone but it seems everyone that comes here doesn't have a clue, it took you guys to figure out the circulator was in the wrong spot.

EdTheHeaterMan

In order to see the actual temperature difference on your radiant loop you need to have 2 identical thermometers that are calibrated to the same temperature and then place them on the supply pipe and the return pipe.  That is the only accurate way to tell what is happening. You can try these Clip on pipe thermometers for not too much money. 

you only know that the supply out of the mixing valve into the floor heat is 100°F and the way those thermometers are connected, may not sample the most accurate temperature reading.

These two thermometers are not telling you what the temperature drop is across the radiant floor zone.   It must be apparent to you because you can't put 100°F water in and get 120°F return water after it heated the floor.  Your return temperature thermometer is measuring the return from all the zones, not just the floor heat zone.

This is the proper thermometer placement, and you can do that easily with the clip on thermometers from Amazon.com

Mark Eatherton

Some observations from Coolarado. BTW, you can recall the cold air that you are sending down here any time now… :-)

As others have noted, first thing you need to do is set the pump and mixing valve up so that the pump is pumping from the common Mix port to the RFH load, then pipe back to the main. Once that's done, if it still doesn't work right then it may be a defective thermal actuation unit in the mixer. But you won't know that until the piping is straightened out.

The system is piped primary secondary, but on flow at design condition, after each connected load at design conditions, the fluid temperature will drop by 20 degrees F (not C for Canadian), meaning that the HXer for the garage will be seeing an entering temperature of 100 degrees F. Essentially the loads are in series with each other at design condition. That will cause issues with the output to the garage, but cars rarely complain… The use of a Low Loss Header would take care of that series load problem, but would require an expensive remodeling of all your near boiler piping. This comment is more for other hydronics people reading this than for your resolution.

Hard to tell with all the crossover piping, but you have to think like water, when it comes to purging. You need a good path to forcibly purge the air out of the radiant floor circuits. Once good and purged, you should be able to see a good flow at the flow meters serving each tube circuit. With the basement being served by Forced Air (FA) and radiant (RFH), if the 2 stage thermostat (assumed) has the FA as stage one, unless there is a blower/pump failure, the RFH will not come on. If that's the case, I'd switch 1st and second stages so that the radiant has primary control over the basement. This way, if the floor fails (pump, mixing valve, air binding etc) the FA will keep the space conditioned. The RFH will raise the Mean Radiant Temperature, which has a lot more comfort to it than does the FA system.

Have your contractor come back and move the pump. Once that's done, you should be able to go further with diagnosis if needed.

Good luck, eh! :-)

ME

RobertJordan

Surprised you need heat in the basement with the copper radiator (uninsulated pipes).

geno907

this was a fun thread to read through, thank you.

Quick observation point, you mentioned the space area was 68° before you started troubleshooting. Just for you information, 68° (20°C) is a standard for design temp for new engineered systems. So, you’re system may not seem like it’s as hot to the touch but it’s well within acceptable limits.

Something else, a perfect system is a beautiful balance between heat produced and heat consumed. Which means a perfect system would NEVER SHUT OFF. Which leads to my question, how many times is you boiler cycling per day?