pump controller for multizone floor heat

[stingry]

Hello everyone
I am starting to plan the piping and controls for my 4 zone in-floor heating system. What have you done to control the pumps on your zones? It seems to me that one can go one of two ways:

1. low voltage thermostats with relays or
2. Line voltage thermostats wired directly into the pumps

The local Menards sells a Taco controller (#SR504-2) which controls the zone pumps with relays. Does anyone know if this type of controller just turns on a pump when the thermostat calls for heat even if other pumps are running or does it sequence the pumps so that only one runs at a time.

As always your replys are appreciated.

Cheers
Steve

 

[sneezer41]

the relays turn on the pumps when a thermostats calls.

i mean no offense, but from the nature of your questions I suggest you do some more studying of radiant systems

 

[Fueler]

Speaking of this, where is a good place to study up?

 

[koditten]

I thinkthis is a very good place to learn about radient heating. When I was planning my system I refered to the GJ quite often. I was able find lots of info and web sites that other members gave me. If you do a search for radient heat in this forumn you will find all sorts of info.

My next questions: Is this for your home or for your shop. What are you using for a heat source? If you are using a boiler, most boiler already have the relay for the pump. My relay on my boiler turns on both my primary and secondary pump. My secondary pump pushes the water thru 3 loops.

The SR504-2 turns on 2 additional zone valves or pumps. You use this when you want one room (zone) to be a different temp from another room(zone). I don't know if I can explain it clearly, but in the case of a garage you have a wide open space that really does not require different temps. So you might have several loops, but they would only be one zone. If this is the case you would use the SR504-1.

Let us know more of your specifics, there will be plenty that want to share there expirences with this type of heating.

 

[stingry]

the relays turn on the pumps when a thermostats calls.

i mean no offense, but from the nature of your questions I suggest you do some more studying of radiant systems

Some offense taken! Let's start over, apparently I did not communicate my question clearly.

This is going to be the floor heat in my new shop, approx 3800 sq ft. It has 4 zones, each zone will have a pump to circulate water in that zone. Each zone will have its own thermostat. It will be an open system similar to this except I will be using an Takagi or that type of water heater, no boiler:

View media item 6771
As I see it, there are two ways to control the zone pumps:

1. Use line voltage (110V) thermostats so that when heat is called for in a zone, the thermostat sends line voltage directly to the pump.

OR

2. Use a commercially available controller that accepts a low voltage (24V) signal from the thermostat and then sends line voltage to the pump via a relay.

What I am asking is what have some of you used out there?

As for the Taco controller, my question there is whether all zones can be on at the same time or are they operated one at a time?

Thank You

Steve

 

[koditten]

Is the tagaki unit rated with enough btu's to heat a 50 by 75 building. Thats five times as big as I have. I will post later when I get home. By the way, very nice diagram.

 

[koditten]

Stingray:

I'm back again. I was able to read your last post again. I didn't see that you are planning on heating domestic water as well. If I recall properly, it is really frowned up to have the domestic hot water tied in with the heating using check valves. Most places require the use of a heat exchanger so as there is no chance of cross contamination of the 2 system. One of the things I remember when getting my system up this winter that the water was really nasty. I know I would not want that water anywhere near my potable water system.

I don't have any experience with the line voltage thermostats except for the use with forced air torpedo heaters. I seem to rember that they were not very sensitive to the heat in the room. They turned the heater off when the room was overly warm and turned the heater on when the room was uncomfortably cool. I like the professional look of using the Taco relays with thermostats telling the relays to send line voltage to the pumps.

You havn't mentioned the style of the building and insulation. Is this going to have the 2" foam board under and around the perimeter of the slab? You will never be able to heat this big of a space without extra attention paid to the insulation.

If you have time punch in "radientec" in your search engine. This will take you to Radientec's website. They have a huge "commonly asked question" section. Plan on being there a while.

Keep the questions coming. I'm kind of suprised no one else has chimed in with their 2 cents.

Later
Kirk

 

[stingry]

I should have added that the building is very well insulated, 2" EPS under and around the slab, R25 walls and R38-40 ceiling. I used a radiant heating design program from Watts and anything over 100,000 BTU should be more than adequate. The reason for the open system is that the only domestic water I will need is for a sink to wash hands, car washing, etc. I don't see that as a problem, any domestic hot water will first run thru the floor tubes so it won't have a chance to become stagnant. This will save me having a second water heater plus I don't really see the need for antifreeze in the circulating water, at least in my particular situation. It's less efficient than pure water at transfering heat, is costly and is just right down nasty to work with.

I would like to take credit for the diagram but it is off the website of the Radiant Floor Company, located in Vermont.

As far as line voltage thermostats, they vary in quality just like low voltage ones. you get what you pay for. I will probably go with the Taco controller, just wondered if anyone used line voltage thermostats.

Kirk, thank you for your comments.

Cheers
Steve

 

[redsky49]

I would think that for a system as complex as you are proposing a professional installation would be preferred. Is there a particular reason you are attempting this, as opposed to bidding the job out to a contractor experienced in this area? A turnkey installation would certainly simplify the responsibilities should the system not perform up to expectations.

The diagram you have posted does not satisfy the requirements for even a schematic design. I suspect that it was scabbed off a two page sales brochure. It is both incorrect and incomplete. By no means is it an installation drawing and does not serve you well for actual system requirements. Internet 'cut and paste' does not substitute for a proper design.

If you are simply interested in doing your own installation work, see if you can get a properly engineered design from a vendor. Many suppliers will assist you with a basic design package if purchasing all the materials for your project from the same vendor.

As to control voltages, you should expect to provide either a 4-20ma system, or second choice would be 24V. Sometimes you will have a combination of voltages. Before determining system voltages however, you should write a "Sequence of Operation".

A Sequence of Operation will explain precisely how the system will operate. It forces you to think through the entire project, and understand the systems you are installing. For instance, do you actually require four independent zones? Are there four different design conditions or operating hours for these zones? A piping loop does not need to be an independent zone, in fact multiple loops can be controlled as a single zone. In your system, what regulates the heat source? In your line diagram, where is the aquastat for the boiler? How does the system operate if only one zone is calling for heat?

There are a variety of items that have to properly designed, selected, installed and commissioned in order for a hydronic system to function correctly - far more than I have space or patience to list. Please give some thought to an experienced professional engineer or contractor.

Good luck with your project.

As always, offered only as opinion

 

[tdkkart]

Back to controlling pumps:

I'm using 2 of these to control 2 zones and 2 pumps:
http://cgi.ebay.com/Honeywell-R845A...757?pt=LH_DefaultDomain_0&hash=item43a3dd995d

Very simple to wire up, power in, power out, and 2 wires from the thermostat. Cheap, simple and dead reliable.

 

[stingry]

I would think that for a system as complex as you are proposing a professional installation would be preferred.
Not that complex in my opinion, this is a relatively simple system.
Is there a particular reason you are attempting this, as opposed to bidding the job out to a contractor experienced in this area? A turnkey installation would certainly simplify the responsibilities should the system not perform up to expectations.
Why pay someone to do what I am perfectly able to do myself. Plus, I love a challenge!

The diagram you have posted does not satisfy the requirements for even a schematic design. I suspect that it was scabbed off a two page sales brochure. It is both incorrect and incomplete. By no means is it an installation drawing and does not serve you well for actual system requirements. Internet 'cut and paste' does not substitute for a proper design.

If you are simply interested in doing your own installation work, see if you can get a properly engineered design from a vendor. Many suppliers will assist you with a basic design package if purchasing all the materials for your project from the same vendor.

As to control voltages, you should expect to provide either a 4-20ma system, or second choice would be 24V. Sometimes you will have a combination of voltages. Before determining system voltages however, you should write a "Sequence of Operation".

A Sequence of Operation will explain precisely how the system will operate. It forces you to think through the entire project, and understand the systems you are installing. For instance, do you actually require four independent zones? Are there four different design conditions or operating hours for these zones? A piping loop does not need to be an independent zone, in fact multiple loops can be controlled as a single zone.
Actually I have twelve loops, four zones.
In your system, what regulates the heat source? In your line diagram, where is the aquastat for the boiler?
Read my post, No boiler just a flow actuated on demand water heater
How does the system operate if only one zone is calling for heat?
pump comes on, heater senses flow and supplies heated water.

There are a variety of items that have to properly designed, selected, installed and commissioned in order for a hydronic system to function correctly - far more than I have space or patience to list. Please give some thought to an experienced professional engineer or contractor. Just a wild-assed guess here, but do you happen to professionally design and install these systems? I am a Mechanical Engineer so I do understand the basic principles of how these systems work. but do not have a lot of real world experience with these systems except for having two self serve carwashes that do have snow melt systems. I do appreciate your comments but I think you tend to overcomplicate these systems. I realize there are very complex systems out there that require high levels of engineering but this is not one of them.

Cheers
Steve

 

[stingry]

Back to controlling pumps:

I'm using 2 of these to control 2 zones and 2 pumps:
http://cgi.ebay.com/Honeywell-R845A...757?pt=LH_DefaultDomain_0&hash=item43a3dd995d

Very simple to wire up, power in, power out, and 2 wires from the thermostat. Cheap, simple and dead reliable.

Thank You
This is the type of information that I am looking for.

Cheers
Steve

 

[sneezer41]

First, this is not a great place to learn about radiant heat, heatinghelp.com IS a great place to learn.

I don't think you need a pro, but slow down and research, you will be happier in the end.

Second, I too frown on an open system, but if it is what you want, I won't bother with details

honestly, check out the pricing on a real boiler rather than a tankless, yes they work, but the install is going to be more prone to head scratching problems and the efficiency is not a good as you would expect.

do you really have 3 zones in the shop, or is it just 3 loops? If you fire all 3 at the same time then they are not really zones

 

[koditten]

You were able to ask in one question that I couildn't make clear with 3 posts. I too was wondering if we had a conflict of terms, zones vs. loops. I think we are getting somewhere now.

I too started with an on-demand water heater. I got rid of that thing in a hurry. I had too many problems with flow. When your system requires more heat, the water heater just slows down the flow so that the water spend more time in contact with the water heater heat exchanger. So if you look at the big picture you gain nothing. You either get slower moving water at a higher temp or faster moving water at lower temp. These are things that will make you say WTF when you are trying to balance your loops.

Another thing that I hated was how noisy the on demand water heater was. I need my piece and quiet.

It didn't take me much research to decide that a boiler is the one of the best ways to go.

 

[tdkkart]

Thank You
This is the type of information that I am looking for.

You're welcome.
BTW, those thermostat relays require nothing more than a very simple switch type thermostat, the relay box provides the voltage.

In case you haven't seen it, here is a very helpful document:
http://zurn.com/images/pdf/ZPM02101.pdf


Pay no attention to RedSky, he jumps into every one of these conversations and does nothing but tell people that what they're doing is wrong or can't be done. He's one of those that believe that the average person cannot open a bread sack without professional help.
In reality, I suspect he lives a nursing home heated by electric baseboards.

 

[stingry]

Thanks Guys, Now we're getting somewhere. I have did extensive research on radiant floor systems and am confortable with theory but I want some real life experiences so I don't try to reinvent the wheel.

One last time: 12 Loops 4 zones Probably overkill but I have four distinct areas of my shop and want to have the ability to regulate them separately. Definately want to keep the office warmer than the rest and I suspect that in the end will keep the other three areas the same temp but at least I have the option.

Koditten, interesting revelations about on demand water heaters. The only one that I have looked at is Tagaki, are you saying that their advertised flow rate for a certain temp rise is not true?

Good stuff guys, keep it coming.

Cheers
Steve

 

[scuba0459]

I have 4 loops of 250'. Heat comes from a domestic hot water heater. I used a 24v contactor to control the one pump and it is switched on and off by a thermostat. I put the thermostat in my office area and it is set at 15c at 5' from the floor. The office is nice and warm and the shop is cooler by a few degrees. I am real happy with how simple it is and how well it works. One day I will post some pictures but there really is not much to see. I use the same heater for 2 sinks and a shower.

Albert

 

[stingry]

I have 4 loops of 250'. Heat comes from a domestic hot water heater. I used a 24v contactor to control the one pump and it is switched on and off by a thermostat. I put the thermostat in my office area and it is set at 15c at 5' from the floor. The office is nice and warm and the shop is cooler by a few degrees. I am real happy with how simple it is and how well it works. One day I will post some pictures but there really is not much to see. I use the same heater for 2 sinks and a shower.
Albert

How's that working? This is what I want to do. I would like to see a picture if you do have time, particularly how the domestic water interfaces with the floor heat.

Thanks

Steve

 

[trythis]

http://www.bdmfginc.com/hss_controls.pdf

I have one of these. It does exactly what you want to do. Thermostats kick on the zone pumps the tank temperature, boiler or heat pump is controlled by the aquastat. One main thermostat converts it to cooling or heating, or it can be heat only.

They make it for this, but I dont have one.
http://www.bdmfginc.com/hss_specs.pdf

 

[scuba0459]

Steve

I won't be able to get you a picture for a week or so. Basically the cold water supply runs into the floor and then from the floor to the heater. Their is a check valve to stop the hot water from flowing back into the cold water. The system works well heating the floor but I have not yet connected the sinks, etc.

To put it another way... When you turn on a hot water faucet the incoming water flows thru the floor, into the hot water heater and the hot water flows out of the faucet.

The system is identical to what Radient tech has on their website but the system was designed by my plumber and his buddy, the plumbing inspector.

 

[scuba0459]

Steve

At the top of this string is the image you posted. My system is either identical or close to identical to the drawing. The differences are that I have one pump, no pressure gauges and no valves to or from the loops. I would love to have added thermometers from every loop so I could see how cold the water is from the loops that have lots of outside walls but they are not really needed.


Albert

 

[Throttlejockey]

You were able to ask in one question that I couildn't make clear with 3 posts. I too was wondering if we had a conflict of terms, zones vs. loops. I think we are getting somewhere now.

I too started with an on-demand water heater. I got rid of that thing in a hurry. I had too many problems with flow. When your system requires more heat, the water heater just slows down the flow so that the water spend more time in contact with the water heater heat exchanger. So if you look at the big picture you gain nothing. You either get slower moving water at a higher temp or faster moving water at lower temp. These are things that will make you say WTF when you are trying to balance your loops.

Another thing that I hated was how noisy the on demand water heater was. I need my piece and quiet.

It didn't take me much research to decide that a boiler is the one of the best ways to go.

What heater were you using and how big was the area you were heating? The Takagi JR I just got is super quiet. Since I bumped mine up to 122* it's working great now.

 

[Throttlejockey]

Steve

At the top of this string is the image you posted. My system is either identical or close to identical to the drawing. The differences are that I have one pump, no pressure gauges and no valves to or from the loops. I would love to have added thermometers from every loop so I could see how cold the water is from the loops that have lots of outside walls but they are not really needed.


Albert

You really should have thermometers and needle valves on the return loops so you can balance out the temp settings properly.

 

[scuba0459]

I don't know. If I take my IR thermometer and walk along the floor the temperature does not change more that a degree or two all the way across the floor. The building is about 1/3 office and 2/3 workshop with the thermostat in the office. The shop is cooler than the office but that is good as you are more active in the shop than the office.

I have about 7" of concrete so it holds a lot of heat. I had the door open to bring some stuff in. The temperature was -17c outside and it took a couple of minutes for the garage to get back to comfortable but the thermostat in the office did not react. I think this was all good as the floor really can not react that fast. It is also interesting to see how cool the shop can be and still be comfortable compared to having a cold floor and warm air.

So I think that my system will be perfect for me. If I want the shop to be warmer all I will need to do is deal with a gap in the top of the overhead door (an issue for another day and post).

If it turns out the shop needs to be warmer then I will add a fan coil unit to the shop but so far so good.

I think this is turning into a great thread on in floor heat.

 

[koditten]

I think the ODWH was made by Excell. It was really cheap. Both in price and build. The thing was advertised to supply 8.5 gallons of water per minute, more like 3 or 4 gallons per minute. It did not work for me at all. I even tried to use a high head pump and still no luck keeping the thing steadily fireing. I can honestly say that I did not get 20 BTu's of heat into my floor before it would shut down.

The only reason I wanted to go with the ODWH was to conserve floor space. I put the new(used) boiler in the corner and don't really miss the 4 square feet it takes up. I should have know better right from the start. I have a boiler supplied floor hydronic system in my vacation house and I has worked excellent for 6 years.

At that time I wasn't exposed to so many options for used equipment via the internet. I found the same unit I have in my vacation house at a 10th of the price I paid 6 or so years ago.

I heat 1200 square feet plus catherdral cielings in my detached garage. I have not tried to set the thermostat at anything warmer than 55*. That makes the garage the proper temperature for me. I have no doubt that it would take it up to 70* if I so desired.

New boilers might be expensive, but they are the best route for an in floor system, if you have gas or propane. Of course this is my opinion.

I did take a quick look at my gas bill yesterday. I started my boiler half way into my billing cycle. I used 16 dollars more gas than I did last year, and it was a hell of a lot colder than last year at this time. I can't wait to see Januarys bill.

When I started looking at boilers I was thinking I would want an 92% efficient unit. After quickly doing the math, I figured I would be dead before the gas savings vs the extra cost of an energy efficient unit evened out. 87% vs 92% just isn't worth the extra 1500 to 2000 bucks. Plus I didn't want the headaches of all the extra electronics. I have always worried about the voltage sags I might induce when I run the welders or plasma cutter.

Thanks for letting me ramble on. I just spent the last 2 days changing out U-joints and the exhaust on my truck. I would never even thought about doing this job this time of year on a cold concrete floor. The floor was the best place to be working.

In case you are wondering, the boiler is made by LAARS/Teledyne and is a 75K unit(68K output).

 

[tdkkart]

I think the ODWH was made by Excell. It was really cheap. Both in price and build. The thing was advertised to supply 8.5 gallons of water per minute, more like 3 or 4 gallons per minute. It did not work for me at all. I even tried to use a high head pump and still no luck keeping the thing steadily fireing. I can honestly say that I did not get 20 BTu's of heat into my floor before it would shut down.

We all need and welcome all the information we can get from every member of this board, however to totally dismiss all On Demand Water Heaters based on your single experience would be just flat wrong. There are thousands of these heaters being used for this application with no issues whatsoever.
I do know that there were some issues with units shutting down due to lack of flow. I believe the technology has since changed on many brands. I know there are several people on this board using Tagaki heaters with good success.

On demand heaters are a very valid option. Do not write them off based on one person's problems.

 

[koditten]

Yep, I agree. The only thing I know is boilers work. I had a bad expirience with the ODWH that I went with. I wasn't going down that road again. Only thing I know is I will never miss what I never used. If it sounded like I was totally dismissing ODWH's, I apologize. That's unfair for me to do that.

Later

 

[overdriv]

Looking at your schematic, wouldn't it be better to bring the cold water supply into the line coming back FROM the zones into the water heater than to temper the hot water going out to the zones??

Some offense taken! Let's start over, apparently I did not communicate my question clearly.

This is going to be the floor heat in my new shop, approx 3800 sq ft. It has 4 zones, each zone will have a pump to circulate water in that zone. Each zone will have its own thermostat. It will be an open system similar to this except I will be using an Takagi or that type of water heater, no boiler:

View media item 6771
As I see it, there are two ways to control the zone pumps:

1. Use line voltage (110V) thermostats so that when heat is called for in a zone, the thermostat sends line voltage directly to the pump.

OR

2. Use a commercially available controller that accepts a low voltage (24V) signal from the thermostat and then sends line voltage to the pump via a relay.

What I am asking is what have some of you used out there?

As for the Taco controller, my question there is whether all zones can be on at the same time or are they operated one at a time?

Thank You

Steve

 

[REDSHELBY]

I would use flo check pumps and a Taco 3 zone controler. All zones can be ran at the same time with this controler. Do not forget the presure relief.

 

[stingry]

Looking at your schematic, wouldn't it be better to bring the cold water supply into the line coming back FROM the zones into the water heater than to temper the hot water going out to the zones??

Here's a link to the website where I copied the diagram from. They talk about why they run the cold water thru the floor loops first. They say it will prevent stagnation of water in the loops.

http://www.radiantcompany.com/system/open.shtml


Steve

 

[overdriv]

Thanks for posting the link. I understand now.