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Dave H

Dave H

Joined on July 12, 2003

Last Post on July 25, 2014

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Another variable

@ July 25, 2014 10:14 AM in Radiant Heat Matrix Other Than Concrete.

That variable would depend upon how you plan to grow in the greenhouse.

If you are growing directly on the ground, than yes concrete is difficult, in pots, not so bad. I would use a concrete base for the pex but make sure it is pitched and drained.

If growing on benches, then you can build it into the benches on the bottom side the radiant heating system.

Also what is your goal for the radiant system? Typically for greenhouse radiant, its used to maintain a root temperature to promote growth. The air temp will be cooler.

Dave H

Delta T in the RFH

@ June 30, 2014 7:46 AM in Help with radiant floor in shop

For projects like this, I usually design around 30 degrees. Allows for longer loops and an easier install overall.

Based upon that, I come in at (97,000/30x500) = 6.5 gpm total

Four loops = 1.6 gpm per loop

Then looking at some pex charts based upon this flow I find 8.8 foot of head loss.

Circ size just for the radiant floor is 6.5 gpm at 8.8 FOH.

With this info, you end up right on the 007 curve. But I don't know the rest of the system, mix valves, ....... so the 008 also works great. As well as the 0015, on speed medium.

The larger the Delta T in radiant, especially in a shop allows for more "off the shelf" circs and components.

Dave H

Existing heat source

@ May 1, 2014 10:52 AM in New workshop- Help with options

What do have for a heat source in the house?

If you already have a boiler, it may have enough horsepower to heat both the house and the workshop.

You might want to look into preinsulated/jacketed pex systems like Ecoflex to run underground. Eliminate the venting at the workshop, running gas lines, new meters......

and since you were going radiant, the water temp can be lower in the pipe and lower any losses you could experience

Dave H.

I-Valve, setpoint or ODR

@ April 6, 2014 10:58 AM in Taco I Series Mixing Valve not working?


the i-valves can be purchased either with setpoint temperature or outdoor reset. Just clarify which one you have.

Also, did you happen to remove the power head when installing in valve body?
And if you did, do you know if the valve stem was rotated without the motor head?
The reason I ask, is that the head can be mounted on the valve stem only one way, but it can be mounted on the valve posts differently.

You may be rotated 180 degrees.

Also, you probably do not need the boiler return sensor (already piped primary secondary) and that may be limiting the operation of the valve. power down the unit and disconnect the sensor.

Or just call Tech Services at Taco to review your system while you are standing in front of it.

Dave H

Its all about the math!

@ March 23, 2014 9:00 AM in Viega design?

Loop length's by manufacturers install guide guide are just that, a guide. Rule of thumb. Guesstimates.
Doing the math will reveal on each project what the loop lengths will need to be. I am just finishing up my house and with working the math right, I have over 300 foot loops in my house. With 3/8" pex!
It made sense, heat loads were low, flow rates, head loss and off the shelf circs.
I ended up with a 6 loop manifold upstairs. If i followed "max loop length recommendations", this manifold would have been a 10 looper. Adds material cost, labor costs and space (10 loop manifolds don't fit to well in a linen closet)

Trust the math, if you do it, you can never, ever be wrong!

Dave H

Flow readings

@ February 17, 2014 10:43 AM in Taco bumble bee flow meter accuracy

The readings on ECM circs are an estimate. The algorithum's used are based upon the RPM of the motor, not the actual flow.

Not much in the way of

@ January 27, 2014 4:17 PM in AHR attendees, What did you see?

......product. I was soooo busy talking with people at the "Emerald City" that I barely had a chance to wander the show floor. It was busy, exciting, fun.....lots of different emotions at one of the largest places where us freaks have a chance to hang out.

Saw lots of old friends that I hadn't seen in a while, met people for the first time that I had only met here on the "interwebs" or on the phone.

And then tons of guests for the first time. When I got home, the most the family got out of me were one word sentences, I was shot!

Can't wait till next time!

Dave H.


@ January 27, 2014 2:51 PM in Taco I series Mixing valves?

I see no issue with using the two in the system. Modulate the water temp with the i-valve and let the BumbleBee do its thing.

As for controlling, the i-valve does not have to be activated on a call for heat. Supply 24volt power and hook up the sensors and it will modulate. It can accept an endswitch call form a zone relay.

As for the circulator, it depends upon how many zones (if any) you have planned and how the zoning procedure is setup (zone valves or pumps)

Dave H

pumps and i-Valves

@ January 27, 2014 2:47 PM in Taco I series Mixing valves?


Take a look here for the i-valve instructions.
In particular take a look on page 2 the graphic labeled "3-way iseries valves". This gives you the best description for what you are looking to do.

Use the BumbleBee for the system loop circulator. The boiler loop circulator will probably be specified by the boiler chosen. If using a mod-con boiler, I would suggest the BumbleBee for the boiler loop in the Delta T mode. If this size circ fits, you can use it in the constant speed mode.

Dave H.

Splitting to three zones,

@ January 14, 2014 9:46 AM in Upgrade to old system

Just splitting up the zones and the radiation part will help with the comfort levels in the home. You've got different types of radiation and they respond differently as you can tell.

The front satisfies quickly therefor starving the back of the house for heat. Separating the zones with zone valves will let each area run until comfortable. However, doing the math with ensure that the size of the zone valves are accurate and the BumbleBee will provide the correct gpm at maximum demand. If it does not fit the demand of the system, you can still look at a 00VDT to get the same results.
Adding outdoor reset will also help with the economy of operation but will not adjust the heat delivery to the room. Meaning, if all you do is add reset and change nothing else, you will experience the same situation as you have now.

Dave H.

Zone Sentries,

@ January 14, 2014 9:21 AM in Wiring Lochinvar Knight + single Grundfos Alpha

The Zone Sentries have a dedicated end switch. This contact closes when the valve is open.
When wired to a ZVC controller, the endswitch to the boiler won't close until there is a thermostat call AND the Zone Sentry endswitch closes.

Dave H.


@ January 9, 2014 8:38 AM in Taco Zone Controller and Universal Timer Card? What is needed?

Taco has recently updated all of the zone controllers. In the past you were able to add in the PC-610. However, the new -4 controllers eliminated all of the add-on cards and instead added all the capability of the cards to the board themselves.

So to achieve what you need, you just need to make sure if you add the ZVC controller, wire in the zone valves and circulator.

Here are the options you have for cycling the ZV and circ

Pump Exercise Operation:When the dip switch is set to ON, the solid
state timer cycles all the zone valves and circulating pumps that are
attached to the Expandable Zone Valve Control at the selected time
interval. The time interval can be set for the valves and pumps to run
for either 30 seconds every 2 weeks or for 4 minutes every 24 hours.

Here is a link to the ZVC


Dave H.


@ January 7, 2014 2:18 PM in Life Expectancy of VDT

As Alan said, it depends and there are too many variables as to why a component may fail.

With that being said, the 00-VDT has been around for about 10 years already. It is based upon existing 00 circulator design. The only thing different between the two is the on-board controller and the sensors.
If needed, is can be repaired using standard replacement parts from 00's.

Dave H.

Keep it close

@ January 7, 2014 10:07 AM in under cabinet heating

Or even slightly under the cabinets. Don't keep the tube too far away from the cabinets because people stand nice and close and like Gordy said, a little under the cabinet where the plumbing is never hurts.

I have always taken the amount of cabinetry out of the square foot calculation of usable heat emitter. It will also lower the amount of tubing/plates/....needed for the project.

Now when it comes to bathrooms, try to get as much tube in there as possible, under tub decks, showers pans, shower walls. It is typically the only place of the house where you are wet and nekkid at the same time.

Dave H.

Deep setback

@ January 7, 2014 10:02 AM in taco fuel mizer

Deep thermostat setback and an outdoor reset controlling the supply water temperature to the heat emitters can make homeowners think something's not working.
The response time to get the house warm again can take longer especially when you hit a cold snap like this one (45 degrees during the day, 5 that night).

Glad all is OK

Dave H.

FuelMizer Relay

@ January 6, 2014 8:18 AM in taco fuel mizer


Why do you ask, are you?

Dave H

Manifold Balancing

@ December 30, 2013 10:24 AM in Stoppage in a radiant floor line

Is this loop a long loop compared to the others and maybe is the heat loss to this particular area higher than the rest.

Slab application?

Could also be the circulator size?

Manifolds should be balanced based upon the gpm needed which is calculated by the heat loss of the space. Then size the circ accordingly.

Dave H.

This pressure drop

@ December 17, 2013 3:40 PM in Insufficient heat from system

is just for the zone, if the circulator needs to pump other devices, then the associated head loss must be added.

I couldn't get a clear picture of the piping to see the pump and piping

Dave H.

Heat Loss, Heat Loss, Heat Loss......

@ December 17, 2013 11:36 AM in Thought I knew what I was doing.

I am assuming that the thermostat is located in the original radiant room.

So when that thermostat gets satisfied, it shuts down the system.

The heat loss for the porch area is much higher and therfore needs a higher flow rate. So balancing the manifold based upon all having the same flow is causing the porch to be colder.
You can add a zone by adding actuators to the manifold and a thermostat in the porch

Dave H

flow and pressure drop

@ December 17, 2013 11:14 AM in Insufficient heat from system

Did some quick math based upon what is installed.

I found that you need about 2.2 gpm (based upon 39 feet of baseboard at 550 btu's/foot)

The pressure drop of 3/4" pex and 25 elbows and running at 140 degrees comes to about 12.4 foot of head.
So, a 007 is too small of a circulator
The 0015 on speed 1 is perfect, of course if we are estimating some of this info, speed 2 may be better if we are under estimated.

I don't think changing the size of the pex will change much or eliminating elbows.

Dave H.

24 volt power

@ December 16, 2013 10:13 AM in Taco wiring question


24 volt power from a transformer can be higher than expected. You are OK.

Glad everything is working well

House monitoring

@ December 11, 2013 6:00 PM in Keeping circulators always on in unattended home to prevent freeze damage

Why not go with an internet based thermostat?
You can see the temp in the house when you are away and depending upon the stat, they can grab the local weather data to see how cold it is outside.

Other than that, antifreeze should be added if freezing conditions exist inside too often.

Dave H
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