Radiant Heat GPM problem

Zman

Assuming there are not issues with the boiler piping, the easiest fix would be hot rod's suggestion of removing parts of the mixer.
You could turn them to the hottest setting and enable the outdoor reset feature in the boiler to reduce the water temp to the desired temp based on the outside air temp.

Yours is a frustrating problem because the proper design would have been so much simpler and less expensive.

tyronesheat

So the design issue. What would be the correct design. One pump, 8 loop manifold, where is the big mistake with this design? I can give you guys all the data needed if somebody can draw it up for me to get a better understanding of a better design.

Gordy

Detailed pics of near boiler piping.

Zman

The mixing valves are the design issue. The oversized pumps are also a problem. The simpler design would have one pump and zone valves on the system side.
I can see that getting a picture of the piping between the boiler and the mixing valves is difficult. I drawing of the piping would also help.

hot_rod

You have a boiler that needs a dedicated loop, it could be either primary secondary, or a hydraulic separator. Shown below in the first pic.

You may not need all those different mixing valves, if in fact the design calls for the same temperature, you mentioned all the mixers are set the same? If the required temperatures are within 10- 12 degrees of one another no need to add more complication parts, pumps, etc. Without the restrictive mixers a smaller pump could be used or just one pump and zone valves. Shown in the second pic.

I think the radiant manufacturers over sell the mixing in their software designs sometimes, or the installer thinks he needs to have exact mixed temperature to every manifold. Simple is better if it can get the results you need.

I doubt you want to start over, it's possible to improve what you have once we have a clear picture how that primary secondary piping was assembled.

tyronesheat

Ok, when I get home tonight I'll draw up exactly how it is and post some pics of the boiler piping. Thanks for all the help.

tyronesheat

I think these are the key pictures. The picture with the circulator and the grundfos pump. The hot water leaves the boiler, goes through the spirovent. The taco 007 pumps send the water to the circulator through the mixing valve.

Gordy

Well the boiler appears to be piped right P/S.

Pretty hard to make recommendations since you have already purchased the hardware. Your zoning with six pumps? Plus domestic, and primary pump.

As far as the mixer issue. Take mixers apart, and check for clogged screens, and remove flow checks, and I would leave the screens in if they have debris run system, and see if anything changes. I would remove screens once I was sure all debris was removed. Possibly add a wye strainer.

Rich_49

How many circs in total are installed on this system at present ? Looks to me like there are at least 8 and maybe 9 . Please advise .

Some of the comments made here may seem a bit rough but from what I have seen , may be totally warranted . Do not be offended by any of them as most times with solicited uncompensated assistance folks in the know want to help and that usually sounds different than it is .

Unfortunately , it appears that you have a compound issue involving too many , poorly sized circs , piping , and mixing valves that are all allied in beating the hell out of you .

Listen to what is said here with an open mind . While it will certainly seem like you are being beat up , that , I assure you is nobody's intent .

Zman

You are going to need to draw this thing out. The picture with the 3 Taco's on the ceiling is really puzzling..

tyronesheat

Lol, yeah the pics are incredibly hard to make out. So the 3 Taco pumps are for different zones. Actually there will be 4 pumps.
Taco 1- basement baseboard
Taco 2- first floor rad
Taco 3-second floor rad
Taco 4-500sqft room above garage baseboard

The two for radiant heat are primary pumps.

Gordy

So what size tacos?

The primary circ is the boiler circ all others are secondary.

SWEI

I'm getting four Taco pumps for four zones (as described above) plus one on the boiler, along with four radiant floor heat (RFH) zones, each with a mixing valve and a UPS 26-99.

I see the DHW pipe take-offs, and the indirect, but the associated circulator and flow check are out of the frame. That would make ten pumps in total.

A room by room heat loss calc (sorry to sound repetitive, but this is really where it all begins) will tell if those baseboard and radiator zones can run on the same supply water temp (SWT) and whether the RFH zones are reasonably well-balanced. Assuming those prove to be true, your system should be able to run using two ECM secondary pumps, one for all the floor heat zones and one for the radiators and baseboard. I'm not intimate with the U-Control, but AFAIK it does not have the ability to manage an outboard motorized mixing valve. A separate ODR-controlled mixing valve (like a Taco iSeries-R) would be a good fit for those RFH zones.

tyronesheat

All the Tacos are 007 IFC.
Also I want to note that this morning for example my primary loop is reading this. I am running the preset RSU option on the boiler, max 160 min 90.


T

Gordy said:

So what size tacos?

The primary circ is the boiler circ all others are secondary.

tyronesheat

Well I found the big reason I wasn't getting the right gpm. All my screens look like this. Boiler was down for 10 months doing renovation so I assume this all accumulated in the boiler? Maybe some sawdust from when I ran the lines. I taped up the ends but the first line out of the 16 loops was not taped. Dumb rookie! Sludge but either way you guys get the point. I only had time to clean 2 mix valves tonight but I put them back in and set the valve to all the warm and the first speed on the circulators. The manifold reading .15gpm was almost clogged completly with this stuff. I was getting .9-1gpm (even a lilttle bit more) when I sarted the system back up. I am getting the boiler serviced on Friday. I flushed out some of the water and it was really rusty so I assume the by the end of the week I will be running this system pretty good. All flow meters are reading .6. The really dirty screens are from the hot side, the not so dirty screens are from the return side.

Now to optimize this design. Swei I have been reading up on what you said. Trying to learn how that system works. Can I get a little help callculating the head loss. I did it but I would like to see if somebody can get a number so I can compare. Reason is I want to look over these pumps as well as some smaller one as suggested to try and save some energy cost. Thanks for all the ideas and for those who are just reading I think a good note to take home is dirty screens can completly screw up your gpm.....

Gordy

Once cleaned you'll be running 5 degree deltas with those 26-99.

Think about putting in a wye strainer though if you keep having clogging.

Mark Eatherton

No where in this thread do I see the words "oxygen barrier" tubing... Looks like ferrous based rust to me. Flushing won't cure that. Did you use barrier or non barrier tubing???

ME

SWEI

tyronesheat said:

Well I found the big reason I wasn't getting the right gpm. All my screens look like this. Boiler was down for 10 months doing renovation so I assume this all accumulated in the boiler? Maybe some sawdust from when I ran the lines.

Mark called it above, that's oxygen and definitely not sawdust.

Can I get a little help calculating the head loss. I did it but I would like to see if somebody can get a number so I can compare.

I hate to sound like a broken record, but the room-by-room heat loss comes first. From that comes the flow rate for each loop. From those comes the head loss in the radiant loops. The head loss of a 260 foot loop of 1/2" SDR9 PEX carrying 100°F water will range from 1.7 feet to 9 feet as the flow goes from 0.4 to 1.0 GPM.

I think a good note to take home is dirty screens can completely screw up your gpm.....

Modern hydronic systems avoid screens whenever possible. Check out the Caleffi DirtCal and DirtMag, but let's get the design dialed in first...

Gordy

Most radiant loops can be done sub 1 gpm with a 10 delta if properly designed. More like .5to .7 range.

tyronesheat

Thanks for the help guys. Current design working well. Dealing with the in the sun so the boiler reset is a little funny. I don't think my temp gets up past 120 often but I notice I need 130 to get the floor warm. Working on new plumbing but expensive.

tyronesheat

At .7 gpm I get about 15 delta.

Gordy

chances are in a well insulated envelope your floors will never be warm unless approaching design, or below temps outside. Neutral yes. Remember the goal is you want to reach, and hold room set point, not create warm floors. Usually this will lead to overshoot in a well insulated envelope.

Ironman

Mark Eatherton said:

No where in this thread do I see the words "oxygen barrier" tubing... Looks like ferrous based rust to me. Flushing won't cure that. Did you use barrier or non barrier tubing???

ME

I may be wrong (I was once before) but that sure looks like AquaPex which is non barrier.

Gordy

It would be of benefit to get clarification on that to avoid future issues.

tyronesheat

Ironman said:

Mark Eatherton said:

No where in this thread do I see the words "oxygen barrier" tubing... Looks like ferrous based rust to me. Flushing won't cure that. Did you use barrier or non barrier tubing???

ME

I may be wrong (I was once before) but that sure looks like AquaPex which is non barrier.

No its not AquaPex. I used 400ft of 1/2 hePEX Oxygen Barrier PEX Tubing. All wirsbo propex rings, copper adapters.

tyronesheat

Gordy said:

chances are in a well insulated envelope your floors will never be warm unless approaching design, or below temps outside. Neutral yes. Remember the goal is you want to reach, and hold room set point, not create warm floors. Usually this will lead to overshoot in a well insulated envelope.

Ok, my house is only insulated and when it reaches the temperature I have set it shuts off and holds the temp. I wish I used 2x6 for the walls but didn't so I'll have to live with what I have. r15 in the walls and r38 in the ceiling. Also used spray foam in all the cracks, windows, and doors. I guess real test would be when I tile and put the wood floors down? Any suggestions on what to use to insulate the floor? Foil, Kraft, unfaced. I am getting a ton of different answers? Sheetrock is next week. 5/8in garage, 1/2in on the walls and 5/8in on the second floor ceiling. This should help not to mention I have a heat pump on the second floor and a 38000 BTU gas stove on the first floor almost directly in the path of the steps go upstairs. Anyway about that floor insulation? lol

tyronesheat

Another question, can I use Hardiebacker then tile .42 hardie

Ironman

tyronesheat said:

Ironman said:

Mark Eatherton said:

No where in this thread do I see the words "oxygen barrier" tubing... Looks like ferrous based rust to me. Flushing won't cure that. Did you use barrier or non barrier tubing???

ME

I may be wrong (I was once before) but that sure looks like AquaPex which is non barrier.

No its not AquaPex. I used 400ft of 1/2 hePEX Oxygen Barrier PEX Tubing. All wirsbo propex rings, copper adapters.

400' per loop? If that's so, then you will need more than a 007 circ.

tyronesheat

Ironman said:

tyronesheat said:

Ironman said:

Mark Eatherton said:

No where in this thread do I see the words "oxygen barrier" tubing... Looks like ferrous based rust to me. Flushing won't cure that. Did you use barrier or non barrier tubing???

ME

I may be wrong (I was once before) but that sure looks like AquaPex which is non barrier.

No its not AquaPex. I used 400ft of 1/2 hePEX Oxygen Barrier PEX Tubing. All wirsbo propex rings, copper adapters.

400' per loop? If that's so, then you will need more than a 007 circ.

No Im sorry that's a typo. I was saying about 4000ft of pex not 400. I have good measurements now and my longest loop is 270 and my shortest is 240. On each manifold I am 10% within range for the pex that is run on it.

Mark Eatherton

Use kraft insulation, stapling the wings to the bottoms of the joist. Also make certain the outside edges of the rim joist are well insulated. Even with oxygen barrier tube, which "retards" the flow of oxygen, but does not "stop" it, water conditioning is a must. Don't waste time or money on the bubble foil crap, unless you intend to use it for making coozies for holding beer cans... It is useless.

Also, no need for an air gap below the plates. Tough to maintain a perfect gap, which only add's about an .5 R value, if that.

ME