4-way versus injection

[Deleted User]

a twelve speed automatic transmission with a clutch and turbo charger.

I was asked in class the other night why the Euro's don't do more VSI, and the only reason I could come up with is because of the increased cost of operation ($0.16/KWH).

Once you've seen one in operation compared to a hunting 4 way, you'll never go back.

ME

leo g_32

is 4-way mixing a dinosaur?

i can't help but move to the injection camp. i use to be a 4-way proponent, but ever since my partener started doing the majority of the panel work (he uses injection), i have come to feel that injection mixing is a far more accurate and sensible way of controlling the heat output to the radiant floors.

leo g

hot_rod

Very versatile

with the smallest of pumps you can move a lot of BTUs. saves having to purchase different size 4 ways. The small Super Brute will cover most injection needs.

Lots of pump, and control brand choices. Most of the controls give you other features like DHW, reset or setpoint, and some will give you dual mix ability from a single control.

Small diameter piping is all that is needed to inject.

It's fun watching and listening to them ramp up and down.

I've yet to see a 4 way where all the tappings are square to one another, also

hot rod

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Mad Dog

Yeah! and isn't it fun trying to.....

make corrections with your copper piping let alone black pipe???? Mad Dog

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kf_2

4-way vs. injection

not to rain on the injection parade, but I've yet to see a properly sized 4-way valve hunt. Nor have they not been square. However, what I have seen is drasstically improper installations of injection piping and controls.

The thing is they both work when installed and sized properly and I think it is a no-brainer to pipe a 4-way valve. Not to mention that when a 4-way valve is installed on a low flow or large mass boiler two pumps are eliminated.

And I'd sure like to see you get your homeowner heat at 2:00 AM (over the phone) with a bad injection pump.


JMHO
kf

hot_rod

re 4 ways

if 4 ways don't hunt then why even bother with the motor operator?

If your system pump fail, and you don't have a boiler side pump, how do you get circulation through the floor loops. In other words a failed injection pump will result in the same symptom as a failed system pump on a 4 way, no heat :0

I agree properly applied they both accomplish the same task, blending temperatures. Having worked with both I prefer the VS pump method.

hot rod

heatboy

Sorta' depends............

on what you are using to burn fuel. They both have their place. But with what I do, I choose mixing valves. If you are using standard CI boilers that need to maintain temperatures in excess of 140°, VSI makes some sense. If you choose boilers or heat plants that don’t have limits on the return water temps (within reason), mixing valves, especially motorized three way are the most efficient way to mix. Three ways don’t raise return water temperatures at all, increasing boiler efficiencies and using substantially less electric over time compared to VSI.

hb

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Steve Eayrs

I agree with injection pump.

Have seen far too many 4-ways froze and not be able to adjust them at all. And if you can they start to leak. I realize that this does not happen with a motorized 4-way, that exersizes the 4-way, to keep it free, but by then you have spent a lot more than for normal injection pump controls...... And its very easy to get the injection pump going at 4:am. Wire the pump direct and close down the balance valve some on the injection return and its going for the night, but I will admit that in at least 300 tekmar controls, I believe I have only had to do this once. In the few other emergencies I have just popped in a new control, (5 mins. max.) and sent the old control in for a full waranty. Try that with a 4-way vlv.!!

Steve

Arthur

Injection

Hi,
You guys sort of almost use a different language to what I'm used to so can I ask a couple questions
1) What do you mean by injection, is this just mixing?
2) What is VSI?
Thanks

Steve Eayrs

VSI is

> Hi, You guys sort of almost use a different

> language to what I'm used to so can I ask a

> couple questions 1) What do you mean by

> injection, is this just mixing? 2) What is

> VSI? Thanks

Steve Eayrs

VSI is

variable speed injection, similar to what tekmar sells, and is I believe if I'm on the same page with others, "injection" is talking about the same thing.

Steve

Steve Eayrs

I would disagree....

with your statement that 3-way mixing does not raise the return temp. at all. Any time you have displacement from the high temp loop to the low temp you automatically are adjusting the boiler return accordingly, in about the same way you do with any mixing control.
The one difference is you can end up with almost 100% low temps. back to the boiler, but that would not be happening with a good motorize 3-way, if you didn't want it to.
Most of what we do is oil fired and we want to control the returns better, which I can admit has some to do why I favor VSI.

Steve

kf_2

hot rod & steve eayrs

Hot Rod, when I mentioned a failure at 2:00 in the morning I was reffering to a failed actuator compared to a failed VSI pump. In this case all the homeowner has to do is physicaly move the mixing valve lever. Still flow on the system side. Also, what I consider "hunting" commonly occurs when the valve is grossly oversized and just continues to drive back and forth, never finding a home. This does not happen typically.

As far as the comment made by Steve concerning direct wiring the VSI pump, two things. One, it may be a bad pump and not control. Two, can you explain this rewiring to the average homeowner in the middle of the night from your bed. Unless your the type that enjoys being awoken from a sound sleep to run out into the cold night, I was trying to keep you from leaving the house.


kf

hot_rod

I understood, kf

just giving you a hard time But I still say all the tekmar brands 4 ways I installed had the ports drilled and tapped crooked.

hot rod

Mark A. Custis

This was too hot to read and not post.

Remember I AM an air head just learning to move BTUs (heat energy how ever gained) where it is wanted, with water.

The silver and orange system just up and running after two years in design and exicution, contains no mixing valves three or four way that even come close to hooking up at square, plumb, or 90* angle. Then drop the mod motors on after killing one'self to make plumb and square, the job looks very bad. Too late to change, and in a few hundred years, no one will care about straight and level. I will care about sraight and level.

Controls fail, pumps fail, businesses fail, pick your choice, but I am with the veriable speed injection guys. The silver and orange guy thinks I am.

Not much, air head thought, and I am looking at Mr. Rohr's low mass radiant. What do I know?

Your best, my best,

mark



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Alan(CaliforniaRadiant)Forbes

For what it's worth...

The only thing we've used in the last 12 years are 4-way and 3-way mixing vlaves. I've stayed out of all the "injection vs. mixing valve" discussions since I was reasonably happy with what we were doing....until we installed our first injection system last week.

Tekmar injection on staple-up with plates; Wow; talk about a slick system. Most of the controlling I see in hydronic heating is hocus pocus; that is, many times you don't really get a good positive feedback that the system is working properly after the relay clicks in and the boiler turns on; if you're lucky, it works and everyone is happy. But with injection, you can see hear the pump ramp up, you can see the percentage RPM indicator go up on the tekmar controlller and you can feel the temperature go up on the piping after the system pump.

I was very impressed.

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Steve Eayrs

Can you honestly tell me that....

You can explain at 2:am, to the average home owner, how to manually adjust the actuator, which usually means removing the motor?
Steve

This is a responce to "kf"'s comment about being able to get the heat going again, over the phone, and that he could do this with a customer with a 4-way, and not an injection pump. Another big question is how on earth do you even get to the point, (over the phone), of determining the mixing control is the problem? Most customers have a hard time telling you if any of the pumps are running.

heatboy

I stand corrected.

Good point, Steve. I should have said that the motorized three way will allow return water temperature lower than any other method of mixing, which is desired when using low temperature heating equipment. Thanks for calling me on that.

hb

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kf_2

Steve

I'll be honest I have never done this at 2:00 AM. In all fairness to you it was about mid-afternoon on a Sunday.

Customer called, complaint was high temp baseboard was fine, radiant floor was cold. In this case there were several radiant pumps so I assumed that they were probably not all dead, especially after being informed that all the lights on the Taco relay box were on. The motorized 4-way, by the way was closed. It was a Viessmann Boiler and Control, so I was able to have him perform a simple relay test to see if the valve would open. It wouldn't. I then asked the homeowner to disengage the lever from the motor (didn't have to remove motor to do this) and move it towards the open position. I then asked if he felt the pipes getting hot. He did. Based on the outdoor temp at the time, I had him adjust the lever until it read the needed water temp on the temp gauge. Motor was replaced the next day and all was fine.

Now, would I have had the strength and awareness to do this at 2:00 AM. You may be right, I may not have.

The whole phone call by the way, lasted about 15-20 Minutes from my couch.


kf

Rocky

Alan, VSI with plates

I started typing this reply and all of a sudden my post was gone. If this is a duplicate I apologize. This past FAll I ripped out my scorched air furnace and installed a boiler. Two of the three levels of my home were over a crawlspace. They got RTI plates and tube. The upper level got Runtal baseboard and radiators. All controlled by a tekmar 371 with RTU's and utilizing the 371's VSI contacts.
Only reason I went this way was because I've used this same setup on several customers homes. Saw how sweet it worked. Dropped my fuel bill from approximately $225/month on my forced air furnace, to approximately $150/month. AND this now includes all my domestic hot water production via a Weil Gold Plus 60. So, drop about $45/month off electric bill for blower fan and electric water heater, and drop $75/month on fuel bill, and increase both comfort and amount of hot water? Go figure. What's not to like?! HA!

Steve Eayrs

I imagine that we would both agree

that the real issue is using good quality stuff, and maybe not a 4-way vs. injection issue. The better controls Veissmann or Tekmar, etc. are a lot easier to troubleshoot over the phone, that wries crammed in a box. I too use a fair amount of the taco zone controls, and like them.
thanks for the ingaging conversation, Steve