I Got General Questions About New Boiler Install

smithsfan

I'm replacing a TriangleTube solo 110 for a Navien NHB 110. I'm doing the install myself and have a few questions to make sure I'm not missing anything. I do commercial HVAC/R for a living, but primarily commercial refrigeration, so I don't deal with boilers very often.

It's a pretty simple setup. 2 high temp zones and 1 low temp infloor zone. I'll be doing Circ pumps instead of zone valves and a mixing valve for the infloor.
I'll be trying to pipe everything as close to industry standards as possible, I did buy the Navien manifold kit for my primary loop as well.

So here it goes:
1. Boiler flush. Before installing new boiler is there a cleaner you would recommend to run through the system? I heard once new boiler is installed Fernox is a good treatment to add. I'm on a well system. I have a whole house water filter but heard Naviens are sensitive to water quality.

2. Do you cap off the supply/return headers or tie them together. I've seen it done both ways but wondered if it mattered?

3. Is there a min/max distance between your branch circuit tees? Obviously they have to be spaced far enough apart to make room for the circ. pumps.

4. What would be a good drop in replacement for my infloor manifold (pic included) balancing the thing is a nightmare and I think some of the needle valves are sticking.

5. Is there any min distance inbetween 90's 45's etc?

6. I'm replacing a toe-kick heater. Right now it's piped in series with that zone loop. When I repipe do I use 2 monoflow tees or just one on the return?

7. Was not going to have a water makeup line added, if I do this is it necessary to add a LWCO or does the boiler have one built in? Also any opinions on using distilled water in the system?

8. Does it matter if a Tee on the secondary header faces down instead of up?

Thanks in advance, I'm sure i'll have more questions once I start the install!

neilc

go on Utube and search Navien,

hot_rod

4- 6" between tees is fine.

If you are using an air sep, and you should, no need for the 18" before and after it, Caleffi Discal for example.

Flush the old system before you add the new boiler. If the water comes out dirty or black, run a cleaner for a few days, no harm in starting with a clean system.

What is the hardness and TDS of your well? Always good to final fill with DI water. Or blend some well water if it is below 8 GPG.

Tees can face up or down, use a Webstone purge ball valve on every return for quick easy purge.

Of course a Caleffi manifold with universal pex fittings would be best

The boiler may have low pressure lock out, probably not a LWC, which is another good addition.

Download the manual if you don't have one for other recommendations.

mattmia2

Is part of this system actually monoflow? If it is you have to be careful about having enough flow in the monoflow loop to induce flow in the diverter tees through the emitters.

I would pipe the toe kick heater separately from the other emitters even if it is on the same circulator I would have separate balancing valves for it and the rest of that zone so I can balance the 2. It could just be parallel piping where it connects to the emitters and returns from the emitters with a common supply and return to that part of the house.

bucksnort

Can you change your plan on the Navien?

rsilvers

I am changing one of those manifolds now. I have the new one roughed it and working but still need to secure it. I wouldn’t have built it into a wall like this. It could have been on the surface inside a closet. 

Ironman

I’d highly recommend that you consider a fire tube boiler, but not the Navien.

 The massive Kiturami plant which makes the Navien burned down a couple of months ago, so who knows what the future hold for parts or replacements.

smithsfan

Perfect, much appreciated.

smithsfan

bucksnort said:

Can you change your plan on the Navien?

I already bought it, are you speaking of the plant shut down?

mattmia2

They also have had a history of heat exchanger combustion side leaks

smithsfan

Perfect, much appreciated.

mattmia2 said:

They also have had a history of heat exchanger combustion side leaks

There's a lot of them out there. Must be half way decent. Is it because of improper installs?

smithsfan

mattmia2 said:

Is part of this system actually monoflow? If it is you have to be careful about having enough flow in the monoflow loop to induce flow in the diverter tees through the emitters.

I would pipe the toe kick heater separately from the other emitters even if it is on the same circulator I would have separate balancing valves for it and the rest of that zone so I can balance the 2. It could just be parallel piping where it connects to the emitters and returns from the emitters with a common supply and return to that part of the house.

What do you mean by monoflow? I'm wondering if I can just pipe it in parrallel then and call it a day or do I need one of those special Tees?

mattmia2

smithsfan said:

What do you mean by monoflow? I'm wondering if I can just pipe it in parrallel then and call it a day or do I need one of those special Tees?

smithsfan said:

6. I'm replacing a toe-kick heater. Right now it's piped in series with that zone loop. When I repipe do I use 2 monoflow tees or just one on the return?

You asked about monoflow diverter tees. Monoflow is a system where there is a single loop that a circulator pumps through and emitters are connected to that loop through diverter tees instead of using separate supply and return mains. it was a way to use less pipe. In newer systems if they use a single pipe the emitters are usually connected in series. It was common through the 60's or so. Unless you are adding on to such a system you don't need monoflow tees, but i wouldn't put a kickspace eater in series with other emitters, I would put it in parallel. I also wouldn't put your existing emitters in series unless they were designed that way, the water temp falls the further you get from the boiler in a series loop so the further emitters need to be sized for a lower water temp to keep the system balanced. In parallel systems you can balance with balancing valves, but in series all the emitters in series get the same flow.

smithsfan

mattmia2 said:

smithsfan said:

What do you mean by monoflow? I'm wondering if I can just pipe it in parrallel then and call it a day or do I need one of those special Tees?

smithsfan said:

6. I'm replacing a toe-kick heater. Right now it's piped in series with that zone loop. When I repipe do I use 2 monoflow tees or just one on the return?

You asked about monoflow diverter tees. Monoflow is a system where there is a single loop that a circulator pumps through and emitters are connected to that loop through diverter tees instead of using separate supply and return mains. it was a way to use less pipe. In newer systems if they use a single pipe the emitters are usually connected in series. It was common through the 60's or so. Unless you are adding on to such a system you don't need monoflow tees, but i wouldn't put a kickspace eater in series with other emitters, I would put it in parallel. I also wouldn't put your existing emitters in series unless they were designed that way, the water temp falls the further you get from the boiler in a series loop so the further emitters need to be sized for a lower water temp to keep the system balanced. In parallel systems you can balance with balancing valves, but in series all the emitters in series get the same flow.

oh! I gotcha, that makes sense.

SuperTech

smithsfan said:

Perfect, much appreciated.

They also have had a history of heat exchanger combustion side leaks

There's a lot of them out there. Must be half way decent. Is it because of improper installs?

There's a lot of them out there because they are the lowest cost option available.  Also the lowest quality. Endless problems with leaking heat exchangers, exhaust collar failure, control board failures. Most people are lucky if they can get the boiler to outlast the warranty period. These problems have nothing to do with improper installation or maintenance. Look up Pipe Doctor plumbing and heating on YouTube for more information.