Navien NCB -240/110H(NG) No SH Hot Water

[Tatkins]

Navien Not Heating Baseboards but Heating Faucets

I have a Navien comb boiler NCB-240/110HNG for baseboard hydro heating and taps/DHW.

I use Ecobee thermostats and turned off calls for hot water when we had a heat spell. I've since turned on our heating and my thermostats (two zones) have been calling for hot water for my baseboards, but they have not been receiving hot water and my house has not been heated, but I'm still receiving hot water in my faucets and showers.

Images of the system:

https://imgur.com/a/4tK9TiJ

Facts:
- igniter and hot water is being produced
- faucets and shower are receiving hot water
- zone pumps are working
- boiler is producing no error codes
- I purged air and recirculated water to heating zones

Issues:
- baseboard heaters are not receiving hot water to heat the home (when feeling pipes above circulating pumps I don't feel any heat).

Attempts at fixing:
- I bleed/purged the system/SH to get the air out but no change. I’ve also troubleshooted with ecobee and with my taco controller but no problems there.
- flushed relief valves
- cycled power

Request:
- Any recommendations, suggestions, or advice would be greatly appreciated!!

 

[John Gayewski]

It sounds like a setting issue. The heating and water supply heating are different systems within the unit. So you need to make sure the boiler function is enabled. If it's in fact enabled then you'd need to start checking electrical connections to make sure the thermostat signal is being sent to the boiler. Check that all necessary valves are open. Without am error code or seems like it would be settings on the boiler itself that haven't been reset.

 

[Sponsor]

 

[Fitter30]

Here's a service manual look at pages 32,42,43
Call for heating icon ,water and outdoor temperatures if you have outdoor reset, flow rate

https://www.google.com/url?q=https://s6e1619fceb451b6f.jimcontent.com/download/version/1512634722/module/11899834199/name/Navien%2520Gas%2520Boiler%2520NCB-Service-Manual.pdf&sa=U&ved=2ahUKEwjpwdbvrrv_AhUsl4kEHcFmAr0QFnoECAEQAg&usg=AOvVaw0f_zFnGAS4VPN-n6zmeCkX

 

[Tatkins]

Hi! Thank you @Fitter30 & @John Gayewski !

I read and did all you suggested. I've confirmed that the boiler is receiving the thermostat calls and is heating in response to the thermostat calls. However, it is not sending the hot water to any of the zones but it feels like it might possibly be sending cold water instead.

Another interesting discovery:

Please refer to the image with the shoddy drawings.

https://imgur.com/a/OCFMTbC

I believe 'A'/'B' is where the SH hot water should flow from the boiler to the pumps and subsequently to my radiator zones. Then, 'C' is where the DHW flows. When feeling the 'C'/DHW pipe, when calling for DHW, it feels hot. When the thermostats call for SH, the nut shown by 'A' feels hot, but 'B' remains cool and does not heat up.

When everything was running smoothly I could feel the radiating heat from the SH pipes leaving the circulating pumps, but now the only location I felt the heat is on the nut, represented by 'A', but nowhere else on the SH pipes/plumbing.

 

[John Gayewski]

The internal pump in the boiler seems to not be functioning

 

[Fitter30]

Heating in and out is left side look at the manual i sent. Google install manual
DHW right side.
Heating side isn't piped correctly. Should be piped primary secondary loops. Now the boiler doesn't know if it needs one or two zones calling for enough flow. Don't see any check valves. Do the pumps have built in checks. Boiler doesn't have a heating pump just zone pumps. Page 29

NAVIEN NCB-150E INSTALLATION & OPERATION MANUAL Pdf Download

View and Download Navien NCB-150E installation & operation manual online. NCB-E Condensing Combi-Boilers. NCB-150E boiler pdf manual download. Also for: Ncb-180e, Ncb-210e, Ncb-240e.

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