Replacing Calculators with Zone Valves

[JohnDolz]

I am wondering if anyone has simply pulled out their zone circulators and replaced them with Zone valves (or has any thoughts on it)?

I am currently heating my house with very low flow temp off of 1000 gal thermal storage (tied to an Outdoor Reset). I have replaced my 5 zone 007's with 5 Grundfos Alphas and have been able to drop my energy usage to almost nothing and still heat my home to a comfy 72 (to give you an idea I have had flow temps between 95 & 115 this year with pumps running almost constantly). I have just pulled out my main Taco Circulator and replaced it with an Alpha as well, I find that running it at speed 2 (7 GPM) more than meets my need - cutting that pump energy usage down to 25% of what it was. I will be leveraging the plumbing expertise of Tom C. to put in a zone valve for the bypass loop so that 100% of supply goes to the zones when I am heating with wood (my system is tied to my propane boiler which fires if storage drops below a setpoint), we will see how low I can actually get my flow rate.

Once this is in place, I am toying with the idea of pulling out my zone circulators all together. My concern is around what might happen as the zones were not designed to run this way, they were designed in the great American tradition of MORE power (powerful pumps shoving high temp water through the pipes for instant gratification).

I have 3 zones that are standard fintube/basedboard heaters (these draw 1 GPM per the Alpha), 1 zone that runs an underpowered "kickheater" draws 0 GPM per the Alpha and a Modine Hydronic heater in the basement that pulls 3 GPM. My concern is that these 3 are so different from each other, that if I open them all up via Zone Valves and just the 1 Alpha pushing it through my result is going to be a mess.

Any experience with this or any thoughts on what I might get as a result? Thinking I would do it in 3 phases, 1st the baseboard zones and then the others (1 at a time) and see what happens.

 

[JohnDolz]

I am wondering if anyone has simply pulled out their zone circulators and replaced them with Zone valves (or has any thoughts on it)?

I am currently heating my house with very low flow temp off of 1000 gal thermal storage (tied to an Outdoor Reset). I have replaced my 5 zone 007's with 5 Grundfos Alphas and have been able to drop my energy usage to almost nothing and still heat my home to a comfy 72 (to give you an idea I have had flow temps between 95 & 115 this year with pumps running almost constantly). I have just pulled out my main Taco Circulator and replaced it with an Alpha as well, I find that running it at speed 2 (7 GPM) more than meets my need - cutting that pump energy usage down to 25% of what it was. I will be leveraging the plumbing expertise of Tom C. to put in a zone valve for the bypass loop so that 100% of supply goes to the zones when I am heating with wood (my system is tied to my propane boiler which fires if storage drops below a setpoint), we will see how low I can actually get my flow rate.

Once this is in place, I am toying with the idea of pulling out my zone circulators all together. My concern is around what might happen as the zones were not designed to run this way, they were designed in the great American tradition of MORE power (powerful pumps shoving high temp water through the pipes for instant gratification).

I have 3 zones that are standard fintube/basedboard heaters (these draw 1 GPM per the Alpha), 1 zone that runs an underpowered "kickheater" draws 0 GPM per the Alpha and a Modine Hydronic heater in the basement that pulls 3 GPM. My concern is that these 3 are so different from each other, that if I open them all up via Zone Valves and just the 1 Alpha pushing it through my result is going to be a mess.

Any experience with this or any thoughts on what I might get as a result? Thinking I would do it in 3 phases, 1st the baseboard zones and then the others (1 at a time) and see what happens.

Apparently Auto Correct did not like "Circulators" in the title, anyone know how to edit that?

 

[velvetfoot]

will be leveraging the plumbing expertise of Tom C. to put in a zone valve for the bypass loop so that 100% of supply goes to the zones when I am heating with wood (my system is tied to my propane boiler which fires if storage drops below a setpoint), we will see how low I can actually get my flow rate.

If you're doing everything you can to keep the flow down, then you won't be transferring as much heat as you could when the boiler is running, no? Maybe you could arrange things for maximum temperature when the boiler is running, or some other strategy to transfer more load to the emitters when the boiler is firing.

Where does the excess heat go if the zones can't take it and it's on 100% bypass, bypass zone valve is either on or off?

I think you may know, I put in a bypass around my buffer tank so that the boiler gets a return temperature of 155, with a controller adjusting a 3 way mixing valve in response to the load, so that the flow is minimal to the tank. I have the controller hooked up so that the bypass goes to zero percent when the boiler is off, so the flow to zones is through the tank.

I started with 2 circulators, but I found that the boiler pump pumped through the flo checks and circulators when I didn't want to. I wound up adding zone valves, in place of the flo check valves, so the heat stays where is should.

One thing is you have more redundancy now if a circulator craps out. You'd be dependent on one (larger and more $?) circulator and would have to change it out.

 

[JohnDolz]

If you're doing everything you can to keep the flow down, then you won't be transferring as much heat as you could when the boiler is running, no? Maybe you could arrange things for maximum temperature when the boiler is running, or some other strategy to transfer more load to the emitters when the boiler is firing.

Where does the excess heat go if the zones can't take it and it's on 100% bypass, bypass zone valve is either on or off?

The boiler puts all of the heat into the thermal storage tanks, I have it piped with 4 pipes (not ideal but can't/won't rip everything out). The Bypass is in what someone referred to as the "injector loop", really designed for my propane boiler - allows for higher return temps into a low mass condensing boiler. I have this set up for low flow temps so I was toying with the idea of killing the bypass all together in hopes to eliminate or reduce the short cycling of the propane boiler but Triangle Tubes tells me the byspass is also needed to ensure enough flow into the propane boiler. I can't remember the last time the propane boiler fired other than as a backup for DHW.


I think you may know, I put in a bypass around my buffer tank so that the boiler gets a return temperature of 155, with a controller adjusting a 3 way mixing valve in response to the load, so that the flow is minimal to the tank. I have the controller hooked up so that the bypass goes to zero percent when the boiler is off, so the flow to zones is through the tank.

My work life no longer takes me up your way but I do want to come by and see your setup one day!

I started with 2 circulators, but I found that the boiler pump pumped through the flo checks and circulators when I didn't want to. I wound up adding zone valves, in place of the flo check valves, so the heat stays where is should.

One thing is you have more redundancy now if a circulator craps out. You'd be dependent on one (larger and more $?) circulator and would have to change it out.

Based on what I am seeing I can power the whole house with 1 Grundfos Alpha - I have it set right now at Speed 2, 22 Watts, 22 GPM and it is more than keeping up with demand. My Wood Boiler manufacturer in Sweden scratches his head whenever he looks at one of my system diagrams. It always comes back with "x's" through countless pumps and then I have to remind him of why they are there, he laughs and we move on. By the way if I pull out 5 Alpha's, I figure I will have 2 or 3 lifetimes worth of spares.

Any thoughts on how to edit the post title?

 

[Mike Fromme]

I am wondering if anyone has simply pulled out their zone circulators and replaced them with Zone valves (or has any thoughts on it)?


I have 3 zones that are standard fintube/basedboard heaters (these draw 1 GPM per the Alpha), 1 zone that runs an underpowered "kickheater" draws 0 GPM per the Alpha and a Modine Hydronic heater in the basement that pulls 3 GPM. My concern is that these 3 are so different from each other, that if I open them all up via Zone Valves and just the 1 Alpha pushing it through my result is going to be a mess.

Any experience with this or any thoughts on what I might get as a result? Thinking I would do it in 3 phases, 1st the baseboard zones and then the others (1 at a time) and see what happens.

Seems like more $$$ and potential trouble then it's worth...especially sense you already have the alphas. With them you get the flow you need for each zone with minimal pumping costs and you have redundancy.

What are you using to control the circulators? Probably would have to use the 110v pump control output to energize a relay for the zone valves or switch over to a taco ZVc.

 

[Bob Rohr]

technically speaking you would want to determine the flow required (gpm) and the head or pressure drop of each loop. It is possible that a single delta P type of circulator, maybe one, or two Alphas paired, could run the entire system. A balance valve or two maybe to fine tune those micro loads.

Generally speaking zoned, pump type systems are over-pumped, some excessively. If calculations were not performed and pumps sized and balanced properly it is just a guesstimate.


Keep in mind zone valves require some power, and a transformer or two would need to be always energized to power the valves and possibly any electronic, power stealing t-stats.

The only thing accomplished would be less electrical consumption, and less expensive components to replace when one fails. Possibly your ECM pumps on lowest speed run about 17- 20 watts? Depending on the brand and type of zone valves, 3W or less, plus the parasitic loads of the relays etc.

Also, don't trust the GPM readouts on those ECM pumps. I've found them to be off as much as 80% when checked against a lab quality flow meter. On those small ECM circs, that GPM is a calculation not an actual flow measurement as it is on Grundfos Magnas and larger ECMs.

 

[JohnDolz]

Seems like more $$$ and potential trouble then it's worth...especially sense you already have the alphas. With them you get the flow you need for each zone with minimal pumping costs and you have redundancy.

What are you using to control the circulators? Probably would have to use the 110v pump control output to energize a relay for the zone valves or switch over to a taco ZVc.

I stopped thinking about the $'s vs. return a long time ago - just having some fun at this point. Both boilers are designed in Europe and designed to run with without circulators at the zones, just trying to see how close I can get to that "European setup" & seeing how it works (without completely breaking the bank. The circulators are controlled by Room Thermostats via a Taco box.

 

[JohnDolz]

technically speaking you would want to determine the flow required (gpm) and the head or pressure drop of each loop. It is possible that a single delta P type of circulator, maybe one, or two Alphas paired, could run the entire system. A balance valve or two maybe to fine tune those micro loads.

Generally speaking zoned, pump type systems are over-pumped, some excessively. If calculations were not performed and pumps sized and balanced properly it is just a guesstimate.


Keep in mind zone valves require some power, and a transformer or two would need to be always energized to power the valves and possibly any electronic, power stealing t-stats.

The only thing accomplished would be less electrical consumption, and less expensive components to replace when one fails. Possibly your ECM pumps on lowest speed run about 17- 20 watts? Depending on the brand and type of zone valves, 3W or less, plus the parasitic loads of the relays etc.

Also, don't trust the GPM readouts on those ECM pumps. I've found them to be off as much as 80% when checked against a lab quality flow meter. On those small ECM circs, that GPM is a calculation not an actual flow measurement as it is on Grundfos Magnas and larger ECMs.

Thanks Bob. First let me state that I am FAR from being an expert and I appreciate responses like yours as they force me to go do some research and learn a thing or two (luckily I have a knowledgeable friend that looks over my shoulder so I don't get into too much trouble). As I mentioned in another response, the "saving $ aspect" is done at this point. I look at it 2 ways: 1. Fun 2. My wife is younger than me and assuming statistics are correct I don't want to leave her next guy any cash - just a heating system that no plumber understands, a maul & a woodshed.

Regarding Energy usage, I have 3 Alpha's set to their lowest speed using about 6 Watts, another is set on Auto and runs at about 12 Watts, the Modine Heater is on auto and runs at about 18 Watts. I have an additional Alpha in front of a mixing valve, currently I have it a speed 2 using 22 Watts (my hope is that I can run this one on Auto once I put a Zone Valve into the Bypass) .

Basically I am running minimal Wattage plus water at 100+/- degrees to get a house that is 72 degrees so can't imagine I can squeeze out much more efficiency but I am always open to suggestions to improve.

I realize that the GPM on the Alpha's is not accurate but I am hoping it is somewhat consistent so that if I have 3 Zone Circulators running at 1 GPM and the Alpha in front of my mixing valve running at 3 GPM or greater that I am at least pulling enough water through my mixing valve to meet demand (eliminating return water being sucked into the supply manifold).

I read a little about delta P pumps, assuming you are suggesting it to keep the right amount of BTU's going to the emitters. My boiler actually controls a mixing valve to keep flow temperature at the target (target determined by Outdoor reset or in combination with my room sensor should the delta between target indoor temp and actual warrant it, i.e. when I recover from setback at night). Thinking this would eliminate the need for a delta p?

Regarding how my system was spec'd, I knew nothing when it was done but I would bet anything that my plumber just installed it based on is 30 years of experience. My thinking is that if the boiler is firing hot enough water and the pumps are big enough to shove plenty of water through the system, the home owner will be happy and can use the thermostats to "control" the system. My system probably wasn't engineered that extreme but I would think it was laid out based on 30 years of experience and "knowing" what equipment was needed to do the job.

If I could find someone with your knowledge in my area I would probably pay them to come take a look and tell me how close I am to what should actually be in place. You coming to central CT anytime soon, I roast my own coffee.............

 

[maple1]

Not sure how relevant it is to your system - but I have 4 baseboard zones & 1 DHW zone, all zone valved, all pumped by one Alpha on variable speed 1. Zone supplies & returns are on manifolds. Works great. That's the way the system was designed & installed 20 odd years ago, except for the adding of the DHW zone, and swapping in the Alpha for what was originally on older single speed B&G something then later a 15-58 3 speed.

I have all zones partially valved off by their isolation ball valves, to obtain lower flows & lower return temps. So my thinking is with one Alpha, you could throttle the lower flow zones & keep the higher flow zones un-throttled. Adjust/tune your flow in your higher flow zones via pump speed, then slow the other flows down by throttling with ball valves.

(And I wholeheartedly agree with the above comment that most hydronic systems are way overpumped, at least most 'older type' ones. Variable speed pumps should be mandatory for multi-zone systems).

Just some simplistic thinking, no idea whether a change would be 'worth it' or not though...

 

[JohnDolz]

Not sure how relevant it is to your system - but I have 4 baseboard zones & 1 DHW zone, all zone valved, all pumped by one Alpha on variable speed 1. Zone supplies & returns are on manifolds. Works great. That's the way the system was designed & installed 20 odd years ago, except for the adding of the DHW zone, and swapping in the Alpha for what was originally on older single speed B&G something then later a 15-58 3 speed.

I have all zones partially valved off by their isolation ball valves, to obtain lower flows & lower return temps. So my thinking is with one Alpha, you could throttle the lower flow zones & keep the higher flow zones un-throttled. Adjust/tune your flow in your higher flow zones via pump speed, then slow the other flows down by throttling with ball valves.

(And I wholeheartedly agree with the above comment that most hydronic systems are way overpumped, at least most 'older type' ones. Variable speed pumps should be mandatory for multi-zone systems).

Just some simplistic thinking, no idea whether a change would be 'worth it' or not though...

Very relevant, thank you. I had not thought about using my ball valves but that certainly makes sense. I understand Bob's point about everything is a guesstimate unless you actually measure exactly what is going on. The question for me is how much do I want to put into this if I go ahead. Is a guesstimate using ball valves good enough or do I really want it dialed in via balance valves (not sure of what how these work are but imagine that using the ball valve creates the same effect).

Is it worth it, I stopped asking that question a long time ago...........

I know you were involved in a conversation last year around low flow temps. Not sure if you ever looked into using a mixing valve but I can tell you that I continue to get great "MPG" by using low flow temps. I am finding that by lowering my flow volume that I have actually been able to drop my flow temp a bit. Not sure why, I would have expected the opposite. Maybe my pumps are running a bit more delivering more overall BTU's. As you know there are so many variables that for me it is impossible to get to an exact answer. Not sure if our hydronic engineers can get to a definitive conclusion.

 

[maple1]

Yes, I think there were a few conversations last year.

And they were actually pretty good ones, from memory.

From my POV & experience with my setup, I don't think a mixing valve would do me much good, as I would end up making a new fire at the same storage temp anyway. My low flows seem to keep the house at temp & return temps low enough - the main operational difference being that instead of constant flows with constant lower temp, my flows become less top & start as water temps drop (zones stay open longer as water temps drop). Right now the guage in front of me is saying storage is 133/127, I'm still cozy & will make a new fire sometime this afternoon, at which point lower storage temps will likely be in the 110 range.

In other words - not worth it to me.

 

[JohnDolz]

Yes, I think there were a few conversations last year.

And they were actually pretty good ones, from memory.

From my POV & experience with my setup, I don't think a mixing valve would do me much good, as I would end up making a new fire at the same storage temp anyway. My low flows seem to keep the house at temp & return temps low enough - the main operational difference being that instead of constant flows with constant lower temp, my flows become less top & start as water temps drop (zones stay open longer as water temps drop). Right now the guage in front of me is saying storage is 133/127, I'm still cozy & will make a new fire sometime this afternoon, at which point lower storage temps will likely be in the 110 range.

In other words - not worth it to me.

Sounds like you have things working very well. What the mixing valve should get you is longer times between fires, fewer fires in total resulting in less wood consumption. Is it worth it, as I've mentioned I am the wrong guy to ask - I stopped asking that question. Appreciate the dialogue and input!

 

[Bob Rohr]

Thanks Bob. First let me state that I am FAR from being an expert and I appreciate responses like yours as they force me to go do some research and learn a thing or two (luckily I have a knowledgeable friend that looks over my shoulder so I don't get into too much trouble). As I mentioned in another response, the "saving $ aspect" is done at this point. I look at it 2 ways: 1. Fun 2. My wife is younger than me and assuming statistics are correct I don't want to leave her next guy any cash - just a heating system that no plumber understands, a maul & a woodshed.

Regarding Energy usage, I have 3 Alpha's set to their lowest speed using about 6 Watts, another is set on Auto and runs at about 12 Watts, the Modine Heater is on auto and runs at about 18 Watts. I have an additional Alpha in front of a mixing valve, currently I have it a speed 2 using 22 Watts (my hope is that I can run this one on Auto once I put a Zone Valve into the Bypass) .

Basically I am running minimal Wattage plus water at 100+/- degrees to get a house that is 72 degrees so can't imagine I can squeeze out much more efficiency but I am always open to suggestions to improve.

I realize that the GPM on the Alpha's is not accurate but I am hoping it is somewhat consistent so that if I have 3 Zone Circulators running at 1 GPM and the Alpha in front of my mixing valve running at 3 GPM or greater that I am at least pulling enough water through my mixing valve to meet demand (eliminating return water being sucked into the supply manifold).

I read a little about delta P pumps, assuming you are suggesting it to keep the right amount of BTU's going to the emitters. My boiler actually controls a mixing valve to keep flow temperature at the target (target determined by Outdoor reset or in combination with my room sensor should the delta between target indoor temp and actual warrant it, i.e. when I recover from setback at night). Thinking this would eliminate the need for a delta p?

Regarding how my system was spec'd, I knew nothing when it was done but I would bet anything that my plumber just installed it based on is 30 years of experience. My thinking is that if the boiler is firing hot enough water and the pumps are big enough to shove plenty of water through the system, the home owner will be happy and can use the thermostats to "control" the system. My system probably wasn't engineered that extreme but I would think it was laid out based on 30 years of experience and "knowing" what equipment was needed to do the job.

If I could find someone with your knowledge in my area I would probably pay them to come take a look and tell me how close I am to what should actually be in place. You coming to central CT anytime soon, I roast my own coffee.............

Only two way to arrive at the correct answer and optimized system.. crunch the numbers, or trial and error.

Sneak up on the answer by defining the total load on design day conditions.

Or what is the max.output you boiler can provide? 60 KW X 3.41= 204,000 BTU/hr X 78% efficiency, 159,000 but/hr is a reasonable guess to that boilers actual output at optimum burn conditions.

A single Alpha is able to move 15- 16 GPM, 150,000 - 160,000 BTU/ hr depending on the piping and pressure drop of those circuits.

A higher head version Alpha, similar to a 26-99 will be available soon, so there is a single pump answer, once you better define the question

There are some top notch hydronics guys in Ct what town are you near? It may be worth a few hours of their time to give you some design help.

 

[JohnDolz]

Only two way to arrive at the correct answer and optimized system.. crunch the numbers, or trial and error.

Sneak up on the answer by defining the total load on design day conditions.

Or what is the max.output you boiler can provide? 60 KW X 3.41= 204,000 BTU/hr X 78% efficiency, 159,000 but/hr is a reasonable guess to that boilers actual output at optimum burn conditions.

A single Alpha is able to move 15- 16 GPM, 150,000 - 160,000 BTU/ hr depending on the piping and pressure drop of those circuits.

A higher head version Alpha, similar to a 26-99 will be available soon, so there is a single pump answer, once you better define the question

There are some top notch hydronics guys in Ct what town are you near? It may be worth a few hours of their time to give you some design help.

Thanks Bob, the reason for my post is to try to avoid the trial and error approach. I am going to have to keep reading and learn what "crunch the #'s" really means and how I might be able to do that. I am in Burlington, CT about 20 miles west of Hartford. If you could recommend someone I probably would invest in a few hours to have someone help me learn.

Regarding the single Alpha. My boiler is actually "powered" by a Laddomat which moves the water from the boiler to the storage tanks so I am not worried about that. The "single pump approach" I am thinking is an Alpha in front of my shunt/mixing valve to feed the zones. The Laddomat would remain ( I actually have another pump as well tied to my propane boiler. When the propane boiler fires a zone valve closes off my thermal storage loop including the Alpha in front of the shunt valve).

Just for laughs I am attaching a sketch of my system. It is not to scale and doesn't represent all the twists and turns. I drew this up to have the manufacturer help me do some trouble shooting with I installed the thermal storage powered DHW loop. My next piece of tinkering is installing a "normally closed" zone vale in the bypass pipe. I know I am losing flow through the bypass so my thinking is that if I can close it while I am heating from storage, that I will be able to drop flow even further. Effecta is a big believer that the lower I can get the flow, the more efficient usage I can get from my stored BTU's.

For the record when I say "my" next tinkering, that means I come up with a silly idea and a fellow Hearth.com reader comes over and does the actual work - don't want to take any false credit!

 

[JohnDolz]

Only two way to arrive at the correct answer and optimized system.. crunch the numbers, or trial and error.

Sneak up on the answer by defining the total load on design day conditions.

Or what is the max.output you boiler can provide? 60 KW X 3.41= 204,000 BTU/hr X 78% efficiency, 159,000 but/hr is a reasonable guess to that boilers actual output at optimum burn conditions.

A single Alpha is able to move 15- 16 GPM, 150,000 - 160,000 BTU/ hr depending on the piping and pressure drop of those circuits.

A higher head version Alpha, similar to a 26-99 will be available soon, so there is a single pump answer, once you better define the question

There are some top notch hydronics guys in Ct what town are you near? It may be worth a few hours of their time to give you some design help.

As luck would have it I attended the Grundfos webinar today that covered much of what you have been talking about. I got quite an education (or at least learned how much I do not know).