My new furnace plus tankless install with pix!

[hydronicsman]

I have not dealt with that model, yet. But it sounds like a good concept, from what the rep was saying in the seminar I took last summer. Check your bonding

[RoBoTeq]

I like the whole setup. I can't think of how to do better with your sized home.

[commerce48]

I like the whole setup. I can't think of how to do better with your sized home.

Thanks, I was hoping you might appreciate it. You know, I never really took your admonitions against 60K modulators as not being appropriate for small homes to heart, but when everything else was considered, this small two stage turned out to be a better fit for my lifestyle and home.

I'm liking it so far. Of course, setback recovery isn't as brisk as the oversized 60K single stage that it replaced, but the comfort advantages offset that handily.

By the way, for all the recent back and forth, I really learned a lot from your posts. My first post on this forum I believe was in response to a post of yours on filters (a very long and contentious thread) a year ago or so.

[commerce48]

Check your bonding

Kind of too late now! Even if I knew how.

As it happens, they were originally going to use 10 foot sections bonded together. However, the bonding done on the ground outside at 30 degrees failed, so they finished the install the next day after locating 20 foot 3" sections. So one less connection inside my chimney, but a bit of a worry about the connections that remain!

[hydronicsman]

Kind of too late now! Even if I knew how.

As it happens, they were originally going to use 10 foot sections bonded together. However, the bonding done on the ground outside at 30 degrees failed, so they finished the install the next day after locating 20 foot 3" sections. So one less connection inside my chimney, but a bit of a worry about the connections that remain!

Again, the bonding pertains to the gas pipe, not the PVC vent. Bonding=ground. Grounding=protection from lightning strikes and possible perforation of gas pipe.

[commerce48]

Again, the bonding pertains to the gas pipe, not the PVC vent. Bonding=ground. Grounding=protection from lightning strikes and possible perforation of gas pipe.

Sorry, totally missed that!

Now I see what you are talking about, I had to go look at it in my basement. You are referring to the flex gas pipe they used for the last four feet. Do not the metal to metal connectors assure a good ground on the gas piping all the way to the Navien internals? Is a separate jumper required to be sure?

[hydronicsman]

PVC joint connections are "solvent welded". Don't hear that one too often though.

[commerce48]

I guess I should stop editing my posts. Again, more there for you to read in the prior post and a question.

[hydronicsman]

Got it. I don't go backwards too much. Good then on the ground. Should be close to where the pipe enters the house, these days NEC wants #6 stranded either bare or green jacket. Big time enforced in CT.

[commerce48]

Got it. I don't go backwards too much. Good then on the ground. Should be close to where the pipe enters the house, these days NEC wants #6 stranded either bare or green jacket. Big time enforced in CT.

Thank you for bringing that to my attention. I confused the ground jumping across my water meter in the basement with the gas line. Even that ground was removed when my plumber replaced the galvanized pipe with PEX. I'll have to ask him if that interfered with any other important grounds that may have been attached elsewhere along the water line.

So the gas pipe is coming in below grade as I guess would be normal. Does not the underground placement of the main gas line constitute an excellent ground? If not, the close proximity of the gas and water mains into my basement mean that I could ground the gas onto the water main. In fact, there is a humongous quarter inch copper ground clamped to the water main now that I could swing over to the gas main.

What do you think? Should I ground the gas main to the water main, but use #6 stranded instead of the solid copper? Either way, I'll have my plumber do it right. He still has a few other things to finish up.

[hydronicsman]

Apparently the inspectors are looking for positive grounding, and buried pipe won't cut it. Plus, they don't know if newer composite material was used, interrupting path.

If there is a dedicated uninterrupted ground to panel someplace nearby the gas work, at least as heavy gauge as the new gas ground, it is permissible to dual lug and splice the gas ground to it. It must be on the same bond clamp in case of another possible interruption. Check with your town fathers about pre-existing wire. I know that #6 is what is required today.

The idea is to invite stray currents down an easier path than Mr. CSST.

[commerce48]

Vanes in the return ell would/will help to reduce the ESP.

It would have been better if they had taken static readings on the old furnace, before installing the new one. And then taken static readings of the supply and return after installing the new furnace. So that they could tell which duct is the most restrictive.

I'm not sure if this is meaningful information, but on low stage, my returns are absolutely silent. I only hear supply noise, which I believe is only noise of air moving through the supplies.

If in fact the return is a bit restrictive, would the supply side noise be lessened if the return was modified to be less restrictive? That might make it worthwhile for me to explore a new return drop.

[beenthere]

How much would you estimate that a better return design could have lowered static?

.1"

The area blocked off was not in the flow path.

If there was an open space, it was part of the flow path.

Disregarding turbulence, is a 10 x 20 return drop (the narrowest part of the transition) sufficient for 800 CFM?

Its ok, if you don't have a 4" media air filter installed.