Navien Combi boiler/hwh

[Cpeters]

I was going to replace my WeilMclain cga4 with a combi. It's located in my basement which isn't the driest
spot. The Navien installation guide says not to put it in a high humidity area. I do have a dehumidifier but
it does get moisture during rainy periods. Thanks.

 

[Dana]

Have you done the napkin math analysis on the radiation output at condensing temps for this one?

Do the basement walls leak bulk water leaving puddles during rainy periods, or does it just get sticky/moldy/smelly?

 

[Sponsor]

 

[Cpeters]

Have you done the napkin math analysis on the radiation output at condensing temps for this one?

Do the basement walls leak bulk water leaving puddles during rainy periods, or does it just get sticky/moldy/smelly?

I usually just do ball park analysis or nothing gets done. The basement does get water and I put in 2 sump pumps in case one fails.
I do have a dehumidifier witch I set to 70. And it smells and water sits in the sump. Navien says not to install in excessively high
humidity areas. Can any other brand handle high humidity? Is it all about the sensitive electronics? Another brands that can
handle it? Thanks.

 

[Dana]

I've never seen/read the humid-environment spec for a boiler or combi-boiler. Can you point me to where the Navien installation manual they talk about that?

 

[Cpeters]

I've never seen/read the humid-environment spec for a boiler or combi-boiler. Can you point me to where the Navien installation manual they talk about that?

Humidity and Contact with Water


When installing the boiler, avoid places with excessive humidity.

The boiler has electric gas ignition components. Water spray or

droppings can get inside the boiler and damage the ignition

system. The boiler must be installed in a way to ensure that the gas

ignition system components are protected from water (dripping,

spraying, rain, etc.) during operation and service.

 

[Dana]

That reads more like concern about liquid water hazards, not high humidity levels in the air. If it's not going to be exposed to the weather next to a leaky broken basement window or something I wouldn't sweat it. I suspect that language was inserted to keep people in warmer climates from installing it outdoors at the edge of /under a porch or deck or something.

 

[Cpeters]

That reads more like concern about liquid water hazards, not high humidity levels in the air. If it's not going to be exposed to the weather next to a leaky broken basement window or something I wouldn't sweat it. I suspect that language was inserted to keep people in warmer climates from installing it outdoors at the edge of /under a porch or deck or something.

And I'm thinking of paying more and splitting out the boiler and HWH. If there is a problem with one I can just replace it. Like the TVs that had
VCR built in, years ago.

 

[Dana]

What's a VCR?

It's easier to right size the boiler and water heater if they're separate units. If there's room, an indirect water heater operating as the priority zone off a small boiler is cheaper, lower maintenance, and has better hot water delivery than a tankless water heater. HTP's UFT-080W is pre-plumbed to support an indirect, and has a huge modulation range, making it one of the go-to choices for 90% of the houses out there. But a 50-80K Navien can work too, even though it's more work to plumb in an indirect, and requires a hydraulic separator. (The fire tube boilers usually don't need hydraulic separation.)

 

[Cpeters]

What's a VCR?

It's easier to right size the boiler and water heater if they're separate units. If there's room, an indirect water heater operating as the priority zone off a small boiler is cheaper, lower maintenance, and has better hot water delivery than a tankless water heater. HTP's UFT-080W is pre-plumbed to support an indirect, and has a huge modulation range, making it one of the go-to choices for 90% of the houses out there. But a 50-80K Navien can work too, even though it's more work to plumb in an indirect, and requires a hydraulic separator. (The fire tube boilers usually don't need hydraulic separation.)

Too much info to digest. Two units hanging on basement wall, one a instant hwh, the other a condensing boiler. Wish I could have kept the cga4 but
no more chimney. Thanks for all your help.