Combi Boiler System Installation Help

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John Gayewski

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I think your taco 0015 will be oversized. That said I wouldn't be afraid to over size. Try it and let us know what your delta t is. If you end up with 5 or 10 degrees of delta you know it's over sized. The only problem would be short cycling.
 

Fitter30

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1" secondary loop & to the six zones
3 /4" to the two zones
by not connecting make to a perminate line if a leak develops glycol will not get deluted and a backflow device is not needed
 

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Reicherb

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Do you think a 007 is too small? Based on everything I've read slow flow is preferred.

Thanks for the drawing and suggestions!
 

Dana

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Do you think a 007 is too small? Based on everything I've read slow flow is preferred.

Thanks for the drawing and suggestions!

A Taco VR1816 won't break the bank, and offers many more tweaking options. It's about $100 more than the dumbest low efficiency 007s, ~$70 more than an 007e. (Gayewski won't like it, but he's neither paying your power bill nor fully designing your system.) In fixed-speed mode the VR1816 behaves roughly like the 003 when set to minimum speed, but roughly like the 0015 when set to maximum speed, with a whole lot of other stuff in between. But in most systems using on modes other than fixed speed will be more optimal.

In a well designed system the pump would be running a VERY high duty cycle, and a dumb 007 or 0015 would be chewing through a lot of power to no good end. If you have 5 cent electricity that might be no BFD, but in my area residential retail electricity has edged north of 25 cents/kwh, and annual circulator power use has become QUITE relevant for radiant heating systems. Like mileage, your electricity price may vary.

As a general observation, design by web forum is not the best approach to fully optimizing the system. At best it can (hopefully) steer you away from expensive disaster designs requiring major re-work and component swaps to get it do deliver what you want. And even the best designs can be thwarted by incompetent installation. Hydronic heating is not a mere "plug-and-play" exercise in plumbing, hooking up the right ga-zintas into the right ga-zoutas. (Sorry if that antique TV reference is too obscure. :) )
 

Fitter30

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A Taco VR1816 won't break the bank, and offers many more tweaking options. It's about $100 more than the dumbest low efficiency 007s, ~$70 more than an 007e. (Gayewski won't like it, but he's neither paying your power bill nor fully designing your system.) In fixed-speed mode the VR1816 behaves roughly like the 003 when set to minimum speed, but roughly like the 0015 when set to maximum speed, with a whole lot of other stuff in between. But in most systems using on modes other than fixed speed will be more optimal.

In a well designed system the pump would be running a VERY high duty cycle, and a dumb 007 or 0015 would be chewing through a lot of power to no good end. If you have 5 cent electricity that might be no BFD, but in my area residential retail electricity has edged north of 25 cents/kwh, and annual circulator power use has become QUITE relevant for radiant heating systems. Like mileage, your electricity price may vary.

As a general observation, design by web forum is not the best approach to fully optimizing the system. At best it can (hopefully) steer you away from expensive disaster designs requiring major re-work and component swaps to get it do deliver what you want. And even the best designs can be thwarted by incompetent installation. Hydronic heating is not a mere "plug-and-play" exercise in plumbing, hooking up the right ga-zintas into the right ga-zoutas. (Sorry if that antique TV reference is too obscure. :) )
Went to the UK once for a job went over with four engineers before picking a pump, we in the states pick a pump trim the impeller ( 3 ph with a vfd) there line voltage because cost of electric.
 

John Gayewski

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Agree, remote designs aren't great. We had a 3 million dollar house (in Iowa 3 million is crazy) whose designer was a professional hydronic designer. The guy who built the system from our company followed the design, being as it was from a professional. He ended up changing many things after performance wasn't as expected, and yes the pumps were one of the things that didn't line up.

If you over size a pump and then balance it down your amperage draw goes down. There by using less electricity. The pump can run at full speed all it wants but it's moving less water. This keeps the components cool and by passes the complexity of a vfd.

People who sell vfds love to sell all of the "benifits" and convince you that you need to change into these pumps. They bank on people not quite knowing how pumps work.
 

Fitter30

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Agree, remote designs aren't great. We had a 3 million dollar house (in Iowa 3 million is crazy) whose designer was a professional hydronic designer. The guy who built the system from our company followed the design, being as it was from a professional. He ended up changing many things after performance wasn't as expected, and yes the pumps were one of the things that didn't line up.

If you over size a pump and then balance it down your amperage draw goes down. There by using less electricity. The pump can run at full speed all it wants but it's moving less water. This keeps the components cool and by passes the complexity of a vfd.

What is industry standards between residential and commercial is different with both are changing every day.
Vfd's today are not as complex as of years past. Most are plug and play. They are more that a motor starter a centrifugal pump only takes 1.5 revolutions to be at full pressure with a vfd soft start, motor protection , can adjust flow ( can over speed a motor if short of flow within name plate amps) and get feedback from motor failure to amperage.

People who sell vfds love to sell all of the "benifits" and convince you that you need to change into these pumps. They bank on people not quite knowing how pumps work.
 

Reicherb

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Thank you very much!

I'm too cheap to pay for an actual design. I went through the same process on my house (baseboard radiant) and got excellent advise here. A few years later, everything is working very well.
 

Reicherb

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Here is the layout that I have planned. Please look it over and let me know where I'm off. The bottom right corner will be a pressure relief and drain. I may or may not have a water supply. If I don't I'll fill with glycol via the drain. The short cross lines are shut off valves. The electronic controls will likely be located around the corner on another wall.

I've never done a primary and secondary loop install so I'm not super comfortable that I've done that correctly. The primary loop is really short. Is that ok? I don't have a ton of space.

Please tell me where I've gone wrong.

Thanks.
 

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John Gayewski

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Looks good. You should be able to add some valves to fill the system and purge air. You want to be able to fill from one direction opening valves and bleeding air as you move through the system.
 

Fitter30

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Your missing a pump on primary loop. 1600' p of 1/2" pex = 56 k btus 35 per foot. Just want to use one pump to feed all the loops ? Have u though about glycol for freeze protection, boiler control to prioritising dhw and turning boiler on and off. Using manifolds for piping?
 

John Gayewski

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Your missing a pump on primary loop. 1600' p of 1/2" pex = 56 k btus 35 per foot. Just want to use one pump to feed all the loops ? Have u though about glycol for freeze protection, boiler control to prioritising dhw and turning boiler on and off. Using manifolds for piping?
I think the pump is internal
 

Reicherb

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I'm not causing issues if I use 1" piping for both the primary and secondary loops. Right? If the secondary is drawing more volume than the primary can supply, I can simply reduce the flow rate of the secondary circulator. Correct? The system is 100% radiant heat. 1 zone with 6-200ft loops, 2 zones with 1-200ft loop each.
 

John Gayewski

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I'm not causing issues if I use 1" piping for both the primary and secondary loops. Right? If the secondary is drawing more volume than the primary can supply, I can simply reduce the flow rate of the secondary circulator. Correct? The system is 100% radiant heat. 1 zone with 6-200ft loops, 2 zones with 1-200ft loop each.
The pipe size is directly related to how many btus needed. So if you need the same maximum number of btus for the loops they should be the same size.
 
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