iDRY Vacuum Kilns

Sponsors:

Is there a limitation on what 1/25 hp TACO pump and push?

Started by DR_Buck, November 30, 2013, 05:41:49 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

DR_Buck

I've finally got around to hooking up my garage heat from my Central boiler.   The garage is fed by a separate loop and pump at the outdoor furnace.   This goes to a large plate heat exchanger.  I have 2 loops in the garage.  One loop is 3/4" PEX to a ceiling mounted radiator type heat exchanger with a electric fan blower.   The second loop is under the floor.   This loop is really 3 loops of 1/2" PEX under the floor with 3-port manifolds on the input and output.  The manifolds are 3/4" to (3 each) 1/2" outputs.   The three 1/2"  loops are about 250 ft each.

This is not a pressurized system.  I have an open vented fill/expansion tank. 

My problem is I can't get circulation under the floor.   The floor lines ARE NOT BLOCKED.   Using a single TACO 1/25 hp pump between the expansion tank and the 'cold' side of the plate heat exchanger, first I tried paralleling the ceiling loop and floor.  The ceiling worked fine but I got no circulation through the floor.   Then today I series the loops.  Feeding the ceiling first followed by the floor.  Now not even the ceiling heat exchanger is getting flow.

I have not tried just pumping the under floor loops yet.    I have a spare pump.  Should I put separate pumps on the ceiling and floor loops?  Should I put the pump(s) on the hot (output) side of the plate heat exchanger and pump directly into the loops  What else should I try?
Been there, done that.   Never got caught [/b]
Retired and not doing much anymore and still not getting caught

Jim H

I don't know if this will help, but when I did my infloor heat I had the pump on the hot water intake side of the mixing valve. At high water temps the valve uses mostly return water with just a little heated water. I moved the pump to the mixed side of the valve and it worked fine. Also make sure air is purged from the system.  Hope this helps, Jim
2008 LT40HDG28, autoclutch, debarker, stihl 026, 046, ms460 bow, 066, JD 2350 4wd w/245 loader, sawing since '94 fulltime since '98

Holmes

  Each side of the heat exchanger needs a pump. I would use the existing pump  for the ceiling mounted heater. The radiant heat should have a "bigger" pump.  Taco 008 is designed for radiant heat. Pump placement is important, if you are using a mixing valve it must be after the mix temp. port on the feed side of the system.  If your spare pump is an 007 try it ,it may work . A second pump should solve your problem.
Think like a farmer.

Holmes

It is also nice to see your feed and return water temperature on the radiant. If you can add a thermometer to the system now is the time to do it.
Think like a farmer.

albirk

DR Buck it can be hooked up but you will need a manifold for your infloor loops with pump, mixer valve, and bypass. Run your hot and return past your coil to your in floor manifold with a bypass line so your water can return to the stove then put tee's in to feed your coil so you have (185 degree water at the coil and at the in floor manifold)so if the fan kicks on you have hot water at the coil and the cool water returns to the stove and not to the in floor then with the in floor get all the air out of your loops (I use a sump pump and a 5 gallon bucket and fill one loop at a time) once all the air is out you can plug in your pump and start pushing water in the floor 125 to130 degree water it will take so time to heat the floor so have extra wood on hand and you will also need a t- stat on the pump so when it is to temp it will shut of
hope this helps
alan

DR_Buck

Quote from: albirk on December 03, 2013, 05:00:24 AM
DR Buck it can be hooked up but you will need a manifold for your infloor loops with pump, mixer valve, and bypass. Run your hot and return past your coil to your in floor manifold with a bypass line so your water can return to the stove then put tee's in to feed your coil so you have (185 degree water at the coil and at the in floor manifold)so if the fan kicks on you have hot water at the coil and the cool water returns to the stove and not to the in floor then with the in floor get all the air out of your loops (I use a sump pump and a 5 gallon bucket and fill one loop at a time) once all the air is out you can plug in your pump and start pushing water in the floor 125 to130 degree water it will take so time to heat the floor so have extra wood on hand and you will also need a t- stat on the pump so when it is to temp it will shut of
hope this helps
alan

First, as I stated in the original post I have manifolds on the underfloor loops.    I'm not sure why I need a mixing valve.  I've got nothing to mix.   I have a single loop from the furnace to the garage.   Hot goes in, cold goes out.  On the garage side of the plate heat exchanger I have a closed loop with antifreeze in it.

This week I plan on adding the second TACO 007 pump.   One pump will feed the loop under the floor and a second pump will feed a parallel loop to the overhead air exchanger.   Both pumps will pull from a  'T' output from the plate heat exchanger  and 'push'  hot water into the loop.  The other end of each loop will feed a 'T' connector  dumping the cold return back into the reservoir tank. 

This is strictly a "no frills" system that will only be used on those special occasions when it's really cold and I need to work in the garage.   I don't plan on using any thermostats to control temps.   For the under floor loop I'll just shut off  the pump when I don't need heat.    For the air I'll shut off the blower when I'm warm enough and turn it back on when it is cold.   When I'm done, I'll shut off both pumps.

The attached pdf shows the basic layout I plan changing my hookup to this weekend.
Been there, done that.   Never got caught [/b]
Retired and not doing much anymore and still not getting caught

Holmes

Think like a farmer.

albirk

DR
Your (under floor)is this a wood floor or are the line in cement (under floor???)

DR_Buck

Floor is concrete.   PEX is 2-3 inches below surface.
Been there, done that.   Never got caught [/b]
Retired and not doing much anymore and still not getting caught

Thehardway

DR-Buck,

There are a couple things it could be.  I am a little confused about your heat exchanger setup.  You say they are open loop.  Which side is open loop?  Do you have glycol in both loops or just the outdoor boiler side?

That said a couple things could be taking place.  One short 3/4" PEX loop presents much less flow resistance than 3-250' 1/2" pex loops with manifolds.  The water will always follow the path of least resistance.

When using one pump for the whole system (single zone) all pipes must be of the same length and size or flow will not be equal.  The only way around this is the use of control valves.

Another possibility is airlock.  This can be a real problem if there is not a purge point and you do not pre-fill/flush the loops to purge the air before connecting the manifold.

I would put one pump on the ceiling loop and one pump on the floor loop and make sure there is a valve separating the two into two separate zones, alternative would be to use the ceiling loop as the floor manifold supply since you will want slightly cooler water circulating in the floor than in the ceiling.

Was the pipe pressurized when the concrete was poured? If not, you may have a collapsed or kinked pipe in the floor limiting flow. Sometimes concrete can push the ends of loops out as it is poured causing a kink at each end turn.  This will create a high resistance in that pipe circuit and there is no way to fix it.  NOT GOOD! 

Hope this helps.
Norwood LM2000 24HP w/28' bed, Hudson Oscar 18" 32' bed, Woodmaster 718 planer,  Kubota L185D, Stihl 029, Husqvarna 550XP

r.man

Couple of thoughts, firstly are your manifolds made for in floor heating or are they house water manifolds. If they are made for in floor there are valves for each loop in the one manifold and the ones I have seen are out off with little plastic caps that are turned down to adjust flow. For full flow bottom them out. The mixing valve is to limit the temp in the floor pex to avoid damaging the concrete. I believe recommended temp is about 110 degrees F. I have never heard of someone damaging their floor but I have also never known anyone to run much over 110 in concrete. The floor runs need to have the air bled from them and that is where a proper floor manifold comes in handy. It has a bleed fitting on one end of each manifold so you can force house water through each loop while bleeding the excess into a pail to watch for bubbles. In your case turn off two loops, bleed third, switch loops with valves, repeat until done. Without the proper manifold you may need to unhook and do each loop in a more manual way. Short answer is I think you are airlocked and need to fully flood each loop. I doubt you need two pumps but it would make control simple.
Life is too short or my list is too long, not sure which. Dec 2014

maple flats

I was an OWB installer/dealer for about 15 yrs. In that time we did several under floor and other challenging forms of heating. The biggest issue you likely have is trapped air. A Taco 007 does not have enough push or pull to initially fill the system. If both types of heat in your garage are on the same pump, the "water" will always take the path of least resistance. If you have a separate pump for the floor heat, you should be able to use a 007 but will need a way to force all air out. With the 007 even an air bubble that is small can and usually does stop the flow as easily as if there was a marble in the pipe. While we used to connect them  with a pressurized water supply to force all air out, a small bubble can form in use and cause the issue to keep repeating. We found it wiser to go to Taco's 009 when the 007 didn't perform. The 009 has the capacity to push a bubble far better than the 007. If you are on the suction side (pulling rather than pushing) neither pump will be dependable on an open system, they simply will not pull air thru the system.
Under floor heat is nice but you must deal with ups and downs in the tubing. Most likely you are on Pex and no matter how carefully it is installed there is no way to avoid high spots. These high spots in the loop block flow as they fill with air. I would not suggest both push and pull pumps. I suggest you have a way to use well or city water pressure to push the air thru, and to use a Taco 009 pump. However, by specs, a 007 will do the job if you have a balanced system (no air) in the entire system.
Good luck,
Any questions just ask. I'm retired from that since '99 but sometimes I can still recall the various tricks we had to do to get a system to flow properly. At the time, I was usually the "troubleshooter"
logging small time for years but just learning how,  2012 36 HP Mahindra tractor, 3point log arch, 8000# class excavator, lifts 2500# and sets logs on mill precisely where needed, Woodland Mills HM130Max , maple syrup a hobby that consumes my time. looking to learn blacksmithing.

maple flats

I just reread your initial post. I notice you have 3 loops of  1/2" x 250' in the floor heat. I don't have a spec chart anymore, but I think 250' of 1/2" might be approaching the max for a 007 even if the system is balanced, especially since the 3 are sharing the pump flow. Hook up the 009, shut off 2 of the loops at a time and pump thru just 1. After that flows well, close that valve and do the next one and so on. Good luck, the 009 might well do the job even if you don't first force the water through with well or city water, but if not, use that. Try first without water, because the system becomes compromised when you put plain water in and a freeze up is a definite possibility.
By the way, Taco is a good choice, if the motor ever fails you can change it without swapping the whole pump. We used hundreds of them on our systems. The 007 was most common but many needed the 009 so we stocked both.
When running 2 pumps on the same system, you will need a check valve in each line so when one pump comes on it draws from the heat source (the plate heat exchanger) and not through the other set of lines. A simple swing check is all you need on each.
To translate this, a 009 with zero restriction (ft of head) will only produce 13-14 PSI pressure, the 007 is only about 1/3 that max.
logging small time for years but just learning how,  2012 36 HP Mahindra tractor, 3point log arch, 8000# class excavator, lifts 2500# and sets logs on mill precisely where needed, Woodland Mills HM130Max , maple syrup a hobby that consumes my time. looking to learn blacksmithing.

DR_Buck

Thanks for all the suggestions.  I think I found the problem and a solution.   Current configuration is: My supply is 3/4" PEX from the reservoir tank to the plate exchanger.   Output of the heat exchanger (3/4") is Tee'd to feed both pump inputs.    One pump feeds the under-floor loops and the other feeds the overhead air exchanger.   The return from each loop is Tee'd  back to 3/4" PEX then back to the tank.   The tank is vented since the system is not pressurized.  I can make either loop work one at a time, but not both even after removing all air.   

I believe the return is a big part of the problem.   The other part is the under-floor pump.   This weekend I am replacing the under-floor pump with a 008 with internal check valve.  The 008 has almost twice the head pressure as the 007.   I am also changing the return to prevent the return flow from the over head loop from pushing pressure (flow) against the under-floor loop.   I'm doing this by removing the 3/4" Tee to PEX tank connection.   The tank has two ports.  One is 3/4".  That will stay my supply.  The other port is 1-1/2" adapted down to 3/4" to connect to the PEX.   I'm removing the adapters and putting a 1-1/2" Tee directly on the tank with a 3/4" adapter on each side of the Tee.   Each loop will then have essentially it's own return to the tank, removing any back pressure caused by the other loop.  Hopefully this will get it all working.
Been there, done that.   Never got caught [/b]
Retired and not doing much anymore and still not getting caught

MNBobcat


DR_Buck

Quote from: MNBobcat on January 28, 2014, 08:00:42 PM
Did you ever get this fixed?

Works like a champ.  I did exactly as I posted above.   Although it took over 24 hours for the concrete slab to warm up.    At 11º outside my floor got to 70º in some places, but not less than 65º most places.  With the overhead air exchanger working the un-insulated garage can be quite comfy.   

My firewood usage went through the roof though.   :D :D :D :D
Been there, done that.   Never got caught [/b]
Retired and not doing much anymore and still not getting caught

MNBobcat

I go through over 20 cords a year.  :)

I used grundfos brand pumps on my system because they are a 3 speed pump and you can flip a lever to select the desired speed.  It gives me the ability to tune the system somewhat.

Glad to hear you got it working!

LittleJohn

DR_buck, not to be picky but what kind of temps are you runnign a thru the air exchanger and floor loops?  I only ask cause I thought air exchangers require something like 160F water minimum; where in-slab water temps should never exceed 150F. 

My setup in similar to yours, except no air exchanger; just in-slab in garage/shop, reaction times with in-slabs are very long.  Typical calls for heat in the fall when fireing system up can be on the order of hours

QuoteI go through over 20 cords a year
How much SF are you heating MNBobcat - cause I have about 7000sf and currently at 13cords, about half junk wood (3yr old bass wood and poplar)

MNBobcat

Quote from: LittleJohn on February 07, 2014, 10:53:08 AM

QuoteI go through over 20 cords a year
How much SF are you heating MNBobcat - cause I have about 7000sf and currently at 13cords, about half junk wood (3yr old bass wood and poplar)

7,000 sq ft home and hot water.  Also heat my garage to about 45F.  What kind of wood boiler are you using?

DR_Buck

I haven't measured water temps on the garage side of the plate heat exchanger.  The furnace side is 170º to 180º.   This goes int two different loops.  One feeds my 3800sqft drafty farm house where I use a water to air exchanger in the plenum of my heat pump system to provide hot air heat.   The outside unit of the heat pump is powered off during heating season and I use only the OWB.   The second loop from the furnace goes to the plate heat exchanger in the garage.   Everything on the far side of that exchanger is glycol and heats the garage with the separate pumping system described in this thread.     Garage is not heated all the time.  Only when I need to be out there working.   

Since I cut firewood as I need it and have time I have no idea how much I burn.   I just know This year I burned a lot.  I fill the OWB fire box to the top onece a day.  I burn slabs and junk logs from downed trees I drag out of my woods.   When I heat the garage it is 2 or 3 times a day.   If I was to guess I would put it clost to 30 cords this winter.   In the past is was more like 20 to 25 cords.
Been there, done that.   Never got caught [/b]
Retired and not doing much anymore and still not getting caught

WmFritz

Buck... you must be talking about face cords. I suspect LJ and Bobcat are talking full cords. 

I keep my slab loops under 120°f to keep my concrete from busting up.

Glad to hear you got it figured out.
~Bill

2012 Homebuilt Bandmill
1959 Detroit built Ferguson TO35

OneWithWood

Buck is more than likely talking full cords.  I have already gone through 20 cords (60 rick, or face cords) this winter in my CB.
One With Wood
LT40HDG25, Woodmizer DH4000 Kiln

DR_Buck

Quote from: WmFritz on February 07, 2014, 09:05:03 PM
Buck... you must be talking about face cords. I suspect LJ and Bobcat are talking full cords. 

I keep my slab loops under 120°f to keep my concrete from busting up.

Glad to hear you got it figured out.

Full cords just like OWW said above.
Been there, done that.   Never got caught [/b]
Retired and not doing much anymore and still not getting caught

LittleJohn

Just did the math again, counted empty pallets, ...and the answer is 16 FULL cords - so about 1 and a half semi loads of wood.  Burning a bunch of junk wood heating 7000sf

WmFritz



QuoteFull cords just like OWW said above.

OK... I stand corrected. We ARE comparing apples to apples. I never would've guessed somebody from Virginia could burn 25 cords a season. In my mind, I thought your winters were milder.

I'm at about 44° latitude, near Saginaw Bay and it looks like we'll use 7 cord to heat 2200 sq. ft. of a VERY poorly insulated brick ranch, with an indoor gasser.
~Bill

2012 Homebuilt Bandmill
1959 Detroit built Ferguson TO35

Thank You Sponsors!