Navien tankless heater outlet intermittent

Users who are viewing this thread

Tyler26

New Member
Messages
1
Reaction score
0
Points
1
Location
Leduc, Alberta
I have had a Navien tankless hot water tank for a couple years now. It was installed by my home builder. For the first year it worked great but over the last year I have issues with the outlet going to the furnace. It will heat up to its temperature on the thermostat but the water doesn't seem to make it past the circulating pump and into the furnace coils to heat the house . I have had the circulating pump changed already since the tech said they fail sometimes . It worked for a few days then did the same thing again. The only way I've been able to get it to work is by turning the furnace off turning my tap on to get the temperature down, then let it sit. Also it doesn't send out an error code either.
 

Dana

In the trades
Messages
7,889
Reaction score
509
Points
113
Location
01609
What you're calling a "furnace" sounds like it's really an air handler with a heating coil in it. Call it an "air handler" if it doesn't have a burner inside- get's confusing otherwise.

It sounds like there isn't sufficient flow on the heating loop. You replaced the pump, and it still doesn't have enough flow(?), which means it has lime deposits or something in the heat exchanger. Without the exact model number it's hard to get too specific about what to do here, but if you de-lime the Navien (and maybe even the coil in the air handler) it might go another couple of years before it limes up again. If not lime/scale, it could be a clogged filter, or some other restriction.

Liming is usually only a problem when you have fresh potable water running in the heating system. If it's an isolated loop liming is probably not the problem but it could be clogged filter or a mostly shut valve or some other flow restriction.
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks