Replacing boiler - looking for thoughts/suggestions

[davefan66]

Anyone have thoughts on Navian Combi boiler?

 

Current Dunkirk boiler is from 1980. Zone valves and plumbing at the boiler all need replacing due to leaking.  Would cost just under 2k to redo.  Have had issues with other parts for the last 5 years to a tune of about 3-4k.  The new Navian boiler would also replace my aging Takagi tankless hot water heater.  
 

Quoted 11k to replace both units with the Navian combi.  Quoted 9k for a replacement Dunkirk boiler, but would then need to spend another 4k for a tankless water heater.  Was quoted about 3 years ago about 13.5k for a similar system, different brand.

 

I prefer the tried and true boiler over the instant heat system. They are kinda bullet or off if installed correctly.  Cost and efficiency are what’s drawing me to the combi unit.  I would prefer an old time hot water tank, but both units reside in a crawl space that don’t allow for any other hot water option other than tankless.  And I don’t have any other area in the house to out one.  Biggest issue for me is if the combi unit goes down, I lose both heat and hot water.

 

Anyone have thoughts on Navian?  Combi boilers in general?  Is the pricing good/bad?

 

Appreciate any thoughts.

Edited January 31 by davefan66

[Ridgewaycynic2013]

Bride the Second's house had a dinosaur of a hot water tank, which was replaced by a Navian tankless.  The major shortcoming was that the heater was at the back of the house, the bathroom towards the front.  Even with insulated pipes, the hot water delivered wasn't as hot as we were told to expect.  After the installation, we only learned of small tankless heaters placed on these long runs to boost heat.  We would have gladly done that as well, had the contractor mentioned it when costing and installing the initial upgrades.

[Behindenemylines]

Parents installed a full tankless on demand system and have had no issues with it-ever.  
 

water is always hot within seconds and it never runs out.   Key is a good water sources and maintenance for buildup on the coils etc I believe. 

[RkFast]

I have a Navien. I like it. A few thoughts.

 

1. Have someone experienced do the install. I would suggest you go to their website and find a certified installer in your area, at the top of the list. I think its NSS certified or something like that. These things have to be installed just right and the plumbing run for water AND intake and exhaust air done just right, or you will have issues. It then needs to be tuned to what youre using it for in terms of heat (forced air, radiant, hot water, etc.). I dont think they can used for steam heat, if you have that. 

 

2. They are quiet and efficient. But they still require yearly maintainance that can run several hundred dollars. You have the flush the heat exchanger, clean the unit and change the media in the water neutralizer (more on that in a sec).

 

3. They emit very little in terms of out the chimney exhaust, especially if configured for max efficiency. My exhaust is on the side of the house and I can stand right next to the unit while its running and put my nose close to the pipe and smell virtually nothing. The tradeoff is that instead of combustion by-products going out the chimney, they are partially condensed into water vapor in the heat exchanger (the "condensing" technology). And that makes that condensate VERY acidic. So much so that it will irritate your skin a little and most important rust and corrode any metal in site FAST. The solve for this is that the condensate runs through a PH neutralizer which is just a small chamber with limestone in it and then off to the water drains in your house. That limestone needs to be changed every few years. Its not expensive...like $50 and its a DIY thing if youre handy. 

 

4. From what I heard Navien is not the best player in the market in terms of quality. THey used to be BAD but over the last 15 years they got their act teogther. Plumbers do like them becuase they are fairly easy to work on and their tech support is very very good. 

[Gman10]

Is this your forever home? If it is, it's not a bad option, but there are a ton of tankless systems out there that you can choose from. Their tech-support is phenomenal, I would see if one of the local HVAC companies offers a contract. I would imagine parts would probably be rather expensive to replace and I would also assume not every company would carry all of the parts. 
 

Rinnai makes a good product from what I understand. 

Edited February 7 by Gman10

[ExiledInIllinois]

We put in a Lochinvar @ work on the 64 year old (50 at time it went in) system. Seems to be running like a champion the last 14 years.

 

https://lochinvar.com

[davefan66]

On 2/6/2024 at 9:25 AM, RkFast said:

I have a Navien. I like it. A few thoughts.

 

1. Have someone experienced do the install. I would suggest you go to their website and find a certified installer in your area, at the top of the list. I think its NSS certified or something like that. These things have to be installed just right and the plumbing run for water AND intake and exhaust air done just right, or you will have issues. It then needs to be tuned to what youre using it for in terms of heat (forced air, radiant, hot water, etc.). I dont think they can used for steam heat, if you have that. 

 

2. They are quiet and efficient. But they still require yearly maintainance that can run several hundred dollars. You have the flush the heat exchanger, clean the unit and change the media in the water neutralizer (more on that in a sec).

 

3. They emit very little in terms of out the chimney exhaust, especially if configured for max efficiency. My exhaust is on the side of the house and I can stand right next to the unit while its running and put my nose close to the pipe and smell virtually nothing. The tradeoff is that instead of combustion by-products going out the chimney, they are partially condensed into water vapor in the heat exchanger (the "condensing" technology). And that makes that condensate VERY acidic. So much so that it will irritate your skin a little and most important rust and corrode any metal in site FAST. The solve for this is that the condensate runs through a PH neutralizer which is just a small chamber with limestone in it and then off to the water drains in your house. That limestone needs to be changed every few years. Its not expensive...like $50 and its a DIY thing if youre handy. 

 

4. From what I heard Navien is not the best player in the market in terms of quality. THey used to be BAD but over the last 15 years they got their act teogther. Plumbers do like them becuase they are fairly easy to work on and their tech support is very very good. 

 

Where do you drain the condensate? Does that go out the side of rhe house with the air intake? I’m assuming it’s a separate drain.  
 

They are installing today and didn’t realize this was a thing, and will verify its being done properly.

 

Thanks!

[davefan66]

On 2/6/2024 at 7:28 PM, Gman10 said:

Is this your forever home? If it is, it's not a bad option, but there are a ton of tankless systems out there that you can choose from. Their tech-support is phenomenal, I would see if one of the local HVAC companies offers a contract. I would imagine parts would probably be rather expensive to replace and I would also assume not every company would carry all of the parts. 
 

Rinnai makes a good product from what I understand. 

Possibly the “forever” home.  Problem is, boiler needs replacing and I don’t have the access to the crawl space it used to have .  Previous owner built up the floor by the access door.  Can’t get a true hot water tank in there any longer, has to be tankless.  Figured a combi unit hopefully fulfills both needs.  Projected life is 15 years, which is half what a boiler should do.  Boiler should last many, many years if serviced properly.

 

I hear Navien is good customer service, if you are the installer. Installer I am using has serviced my boiler for years. Decent pricing. Installers are knowledgeable and respectful. Quick service.  Was very difficult finding reliable company to service boilers. 

[RkFast]

1 hour ago, davefan66 said:

 

Where do you drain the condensate? Does that go out the side of rhe house with the air intake? I’m assuming it’s a separate drain.  
 

They are installing today and didn’t realize this was a thing, and will verify its being done properly.

 

Thanks!

 

They would probably run the line to a slop sink if you have one or configure a new drain direct into your house sewer main with a trap or tie it into your central air condensate system with a pump somehow. Ask them. And make sure they arent using any metal fittings on it! And ask them about the neutralizer. 

Edited February 8 by RkFast

[davefan66]

49 minutes ago, RkFast said:

 

They would probably run the line to a slop sink if you have one or configure a new drain direct into your house sewer main with a trap or tie it into your central air condensate system with a pump somehow. Ask them. And make sure they arent using any metal fittings on it! And ask them about the neutralizer. 

Gotta ask. No drain in the crawl space. Very dry, none needed.  Also, have septic.  

[RkFast]

23 hours ago, davefan66 said:

Gotta ask. No drain in the crawl space. Very dry, none needed.  Also, have septic.  

 

How did it go?

[davefan66]

1 hour ago, RkFast said:

 

How did it go?

Went well.  Good crew. Did a great job.  Even pulled my old boiler out of the crawl space.  
 

They ended up running the condensate via a small pump to my slop sink.  Tried to drill a hole in the crawl space pad and discharge that way, but I wasn’t a fan of that.  Only issue versus gravity is the pump is a point of failure.

 

Need to tweak the boiler water heat setting I think.  Baseboards are not as warm as usual and the furthest room heated, but not to the usual level.

[RkFast]

57 minutes ago, davefan66 said:

Went well.  Good crew. Did a great job.  Even pulled my old boiler out of the crawl space.  
 

They ended up running the condensate via a small pump to my slop sink.  Tried to drill a hole in the crawl space pad and discharge that way, but I wasn’t a fan of that.  Only issue versus gravity is the pump is a point of failure.

 

Need to tweak the boiler water heat setting I think.  Baseboards are not as warm as usual and the furthest room heated, but not to the usual level.

 

Awesome. They could have gravity drained to dirt but the pump should be fine. Mine's 10 years old and hasnt failed. Remember above where I said you need to replace the media in the neutralizer? Well, now you have to clean the pump, too. Again, not a huge deal. Its a DIY job and Ive done it like three times in the ten years Ive had it. Just regular maintainance....no big deal.

 

If you have baseboard, you may indeed need to go hotter on the heat water temp. At least 160, most likely. Mention to your plumber. 

Edited February 9 by RkFast

[davefan66]

4 hours ago, RkFast said:

 

Awesome. They could have gravity drained to dirt but the pump should be fine. Mine's 10 years old and hasnt failed. Remember above where I said you need to replace the media in the neutralizer? Well, now you have to clean the pump, too. Again, not a huge deal. Its a DIY job and Ive done it like three times in the ten years Ive had it. Just regular maintainance....no big deal.

 

If you have baseboard, you may indeed need to go hotter on the heat water temp. At least 160, most likely. Mention to your plumber. 

Need to get a neutralizer.  On Amazon and Home Depot for 80-150 for an inline type.  Unfortunately had no dirt for it to gravity drain to, pump should be fine I hope.  As for cleaning the pump, I’ll leave that to the heating contractor for when they service the unit.  Getting the service contract, nothing in this unit is anything I can work on.  Old boiler, I changed out the zone valve motors several times over the years.

 

Forgot what they said baseboard was at, but feel it does need to increase.

 

Appreciate the knowledge!