Manifold Setup help needed

[Dave28]

I could use some help on setting up my manifold. I have tried calling and emailing Everhot Inc and only get an answering machine. I have emailed them as well as Pex Universe and no reply. They sent me the installation manual but nothing on how to purge or balance the manifold.

I poured my slab 2 weeks ago and have been pulling my hair out trying to get my system to flow right. I have a 6 port Everhot stainless steel manifold. I have 5 loops in the slab, the 6th port is for a future unit heater for the other part of my shop. With all 5 loops open I can only get about 0.1 GPM. I did find a video on Youtube by Uponor showing how to set theirs up so I used the same process and still no luck.



Here is what I have:

80 gallon hot water heater as my heat source
Grundfos Circulator Pump UPS15-58FRC w/internal flow check
Everhot 6-branch Stainless Steel manifold
5 loops in slab ranging in length from 225' - 250'
6th loop is for a future unit heater
Expansion tank from Lowes (set at 20PSI)

I have the pump mounted on top of the hot side of the water heater. The feed then goes up and across the rafters and back down to the manifold. On the return side I have my expansion tank, it then goes into a T and back down to the cold side of the water heater. On the other side of the T is my house water supply line for the system in which I have installed a black flow preventer. I have even cut 2 drain valves at the high point of the system to purge any air out. I have purge everything so many times I lost count. While I may get a little bit of air out it didn't seem to be enough to cause problems. The pump is putting out anywhere from 25 - 40 PSI. Someone told me that is really high but you would think if it is high I should be able to flow more then 0.1 GPM.

I hope what I described makes sense.

Any help or suggestions would greatly appreciated.

Thanks,
Dave

 

[tdkkart]

A couple pictures of your system might help, much easier to spot a problem if you can actually see it.

Where are you measuring your .1 GPM?? I've got a 4 loop manifold with one flow meter that doesn't seem to work right, shows very little flow, yet the temp in and out of that loop is the same as the other 3 when measured with a temp gun.

 

[Dave28]

tdkkart,

I am reading the .1 GPM at each of the balancing valves. That is the flow at the manifold. I will try to get some pictures of the system. The floor seems to be getting warm, I just don't understand the small flow rate. With a GPM of .1 it would take 20 minutes to flow through one loop.

 

[tdkkart]

Your manifolds look the same as mine, do you have the temp gauges on the input and output?? If so, what are you seeing for a temperature drop from in to out??

I'm running a 3-speed 15-58 pump, 4 loops approx 200' each. With the pump on medium speed, if I shut off all but one loop the flow meter shows approx. .5-.6gpm flow in the remaining loop. Normal running I set them all at approx. .2GPM which gives me a temp drop of 25-30* after the system has been running awhile.

Can you get more than .1gpm if you shut off all but one loop??
Where are you measuring your pressure at?? Seems kinda high, but not sure I've ever checked mine.

 

[Dave28]

I have a pressure/temp gauge right at the pump and a pressure gauge right on the feed line at the manifold. The manifold came with temp gauges already on the manifold. If I open them all I can barely see .1 GPM.

 

[KenB]

Looks like the pump you have is rated for about 19 ft. of head -- half the ~37 ft. of head pressure in your system, assuming 1/2 in. PEX and pure water, according to this: http://www.pexuniverse.com/content/how-size-circulator-pump.


Ken

 

[tdkkart]

Looks like the pump you have is rated for about 19 ft. of head -- half the ~37 ft. of head pressure in your system, assuming 1/2 in. PEX and pure water, according to this: http://www.pexuniverse.com/content/how-size-circulator-pump.

This is what I'm thinking also, I don't like the pressure you're seeing, and just how many feet is "goes up and across the rafters and back down"?? If you're lifting the water 10ft straight up, that's a good portion of what the pump can handle just in that section of pipe alone.(the 15-58 pump is rated for 19ft of head pressure)
My entire system is within 6ft of the floor, with the majority of it below the pump. Yes, the horizontals add to the head calculations, but not nearly as much as lifting the water straight up the wall.

 

[stingry]

I have the pump mounted on top of the hot side of the water heater. The feed then goes up and across the rafters and back down to the manifold. On the return side I have my expansion tank, it then goes into a T and back down to the cold side of the water heater. On the other side of the T is my house water supply line for the system in which I have installed a black flow preventer.
Thanks,
Dave

It sounds like you are using an "open" floor heat system, where you will be using the hot water heater for domestic water also, is this correct? I'm guessing the 25-40 PSI that you are seeing at the gage is house water pressure if you are tied into your domestic water system.


Cheers
Steve

 

[Dave28]

Looks like the pump you have is rated for about 19 ft. of head -- half the ~37 ft. of head pressure in your system, assuming 1/2 in. PEX and pure water, according to this: http://www.pexuniverse.com/content/how-size-circulator-pump.


Ken

Ken, can you explain what you mean a little more?

 

[Dave28]

This is what I'm thinking also, I don't like the pressure you're seeing, and just how many feet is "goes up and across the rafters and back down"?? If you're lifting the water 10ft straight up, that's a good portion of what the pump can handle just in that section of pipe alone.(the 15-58 pump is rated for 19ft of head pressure)
My entire system is within 6ft of the floor, with the majority of it below the pump. Yes, the horizontals add to the head calculations, but not nearly as much as lifting the water straight up the wall.

From the top of the water heater it probably goes up 4' the across the rafters and back down about 4' to the manifold.

 

[Dave28]

It sounds like you are using an "open" floor heat system, where you will be using the hot water heater for domestic water also, is this correct? I'm guessing the 25-40 PSI that you are seeing at the gage is house water pressure if you are tied into your domestic water system.


Cheers
Steve

I am tied into my well just for the purpose of topping off the system when needed. I am not using the hot water for domestic hot water just my floor.

 

[stingry]

I am tied into my well just for the purpose of topping off the system when needed. I am not using the hot water for domestic hot water just my floor.

Is there a valve between the well and the floor heat system and is it turned off when make up water is not needed?

Cheers
Steve

 

[Dave28]

Yeah I had it shut off.

 

[Dave28]

I was talking to a guy at work about my system and he ask where my pump was in relation to the manifold. I told him I had the water heater and pump in the utility room. He said if it is a long run it could cause problems. I just measure the feed and return and they are 32' on the feed and return. Do you think this could cause problems?

More info on the system:
LoopCad said my loops are 264', 250', 226', 223', 222'. I think they may be a little shorter as it appeared I had a little more tubing left over then I thought but these measurements should be close.
.

 

[KenB]

Ken, can you explain what you mean a little more?

I think you need a much bigger pump to overcome the head pressure (resistance) in your system -- at least twice as big as the pump you have. Read the pexuniverse article I linked to estimate how big the pump should be. Also, you mention that it's a closed system, so you should have some antifreeze in it. The higher viscosity adds to the pump size you'll need, compared to pure water. Finally, as you move the liquid faster through the system, you may find the water heater's recovery time is too slow and can't reheat the water quickly enough when it's very cold outside. In this case you may have to consider a boiler.


Ken

 

[Dave28]

Ken, I'm beginning to think you're right on the pump. Pex Universe is the one that suggested the pump I have based on the info I gave them. I had planned to run my design through LoopCad again to check my info but my computer crashed this morning. I am also experiencing problems with a used electric water heater I bought. Thinking of an electric tankless heater. Anyone have advice on that?

 

[KenB]

I've been very happy with my Takagi T-K3 going into its third winter in my 30x40 wooden pole barn. I probably could have gotten away with the smaller T-Kjr, but wanted the extra BTUs running without insulation for the first year (it worked great).

My satisfaction with the Takagi runs somewhat contrary to the reviews in this thread: http://www.garagejournal.com/forum/showthread.php?t=103055&highlight=tankless, so caveat emptor.

Also, just for comparison, I have a closed 50/50 glycol water system with 1200 ft. of PEX, which uses a 1/6 HP Grundfoss 52722512 pump, rated for up to 29 ft. of head.

Ken

 

[overdriv]

Try taking the check valve out of the pump, you don't need it. .1 GPH flow on 5 loops is .5 GPH total flow. That might be what your pump is capable of with your system.

Don't worry so much about the flow, just try to get the drop across the manifolds around 15-20* by adjusting the flows on the loops. It helps to have a IR temp gun when balancing the loops. Also wait till the floor gets up to the desired temp before doing the fine tuning.

Your system will gain pressure as it heats up. Just bleed it off somewhere to zero when it is up to temp. Then the expansion tank will absorb the expansion.

Do you have a air bleeder in the system?

 

[Sureshot]

What is the pressure with the pump off?

Wait 24 hrs for temps to stabilize after an adjustment before making another adjustment.

I think the lift effect is countered by the vacuum effect of the drop much like siphoning once you get the flow going.

Is the pump mounted with the flow vertical? I have had the best luck with that and and air valve in a ****** in a T above the pump so the air can go straight up aand the fluid goes out the side of the T. The ****** gives you some "storage" room for air. I would try to do each circuit individually until you get the air out and good circulation established.

With all the sensors etc maybe you are information overload and it is complicating things.

Get all the air out then run all the valves wide open and give the temp as long as it needs to stabilize(keep a log and use a heat gun) then start fiddling if necessary. Just my opinion though.

 

[Dave28]

Try taking the check valve out of the pump, you don't need it. .1 GPH flow on 5 loops is .5 GPH total flow. That might be what your pump is capable of with your system.

Don't worry so much about the flow, just try to get the drop across the manifolds around 15-20* by adjusting the flows on the loops. It helps to have a IR temp gun when balancing the loops. Also wait till the floor gets up to the desired temp before doing the fine tuning.

Your system will gain pressure as it heats up. Just bleed it off somewhere to zero when it is up to temp. Then the expansion tank will absorb the expansion.

Do you have a air bleeder in the system?

Right now I am having problems with the used hot water heater I bought. I can only get the water temp up to about 90 degrees at the water heater. The water heater keeps kicking in and out and not getting up to full temp. It is also reading about 90 at the manifold and 70 on the return. I am kinda surprised that I have a average floor temp across the garage of about 70 - 72 with the pump on giving me .1GPM. Air temp in the garage is around 60. The only air bleeder I have on the system is the one on the return side of the Everhot manifold. I do have an expansion tank on the return side near the water heater.

Never buy a used Whirlpool EnergySmart water heater. When mine started acting up I did some checking on the net and found out there are a lot of people that have had problems with the water heater mad by US Water Heater.

I am seriously considering an On demand electric water heater, just not sure how to tell what size I would need.

 

[Dave28]

What is the pressure with the pump off?

Wait 24 hrs for temps to stabilize after an adjustment before making another adjustment.

I think the lift effect is countered by the vacuum effect of the drop much like siphoning once you get the flow going.

Is the pump mounted with the flow vertical? I have had the best luck with that and and air valve in a ****** in a T above the pump so the air can go straight up aand the fluid goes out the side of the T. The ****** gives you some "storage" room for air. I would try to do each circuit individually until you get the air out and good circulation established.

With all the sensors etc maybe you are information overload and it is complicating things.

Get all the air out then run all the valves wide open and give the temp as long as it needs to stabilize(keep a log and use a heat gun) then start fiddling if necessary. Just my opinion though.

The pump is mounted vertical. I cut in 2 valves in at the highest point on the feed and return and did get more air out. I think both lines are pretty well purged of air.

I did check the temps with a heat gun and I am averaging 70 - 72 on the floor and about 60 air temp but I do have some areas around the garage door that need attention so I am sure the air temp will come up some.

My computer crashed the other day so I lost all my info on my system but from what I remember LoodCad said I should have around .5GPM on each loop. I just picked up a new computer and plan to download LoopCad again and re-run my system and see what nembers it comes up with. I think as KenB stated my pump is way undersized. It is only 1/25th HP with a max of 19ft of head.

I am looking for help on how to determine what size Ondemand electric water heater I'd need to handle my system.

 

[overdriv]

If you have a 70* floor and 60* air temp, you have some serious heat loss issues to deal with. What is the outside temp?

 

[Dave28]

Temp was in the upper 20s. I still haven't got the unit heater for the other part of my shop and that is cooling the garage down. I still have to insulate the block wall on the back side of the house that is exposed.

 

[overdriv]

Are we talking about a NG water heater or Electric? My two 9X7 garage door are a major source of heat loss in my old part, but it still stays the same temp as the new part (new part has the radiant heat). My floor temp stays around 62-64 degrees so far. Not sure what it will do in teens or single digit temps.

My NG water heater is set to 120*. When the pump turns on it will almost always exhaust the hot water supply, but the water heater will maintain 90* output, or input to the floor, however you want to look at it. It will seldom run long at 90* before the pump shuts off. My difference in input temp and return temp is always between 15-20*.

I have 5 loops 4 of which are 300' long. The fifth loop is 90' long. That's what you get when you aren't there to supervise the install. Anyway, I have to throttle the short loop a lot to get it to match the other loops and they will run .1 to .15 as best I can tell by the little cheesy flow meters. The short loop, I can't see any flow indication at all.

I go by the input and return temps and don't worry about the flow meters. I would suggest you try that approach.

Try to reduce the heat loss or it will cost you a fortune to heat it.