Navien NCB-240E COMBI question

GmaChristina

We have 3 zones for the heater. Should each zone have it's own pump? The 3rd floor will not heat up. Water temp is fine but not radiating out on the top floor. All lines have been bled, all fins cleaned. Water pressure reads fine at the unit. They only installed one pump for all three zones. Repair guys have been out twice. Thermostat is set to 78 on 3rd floor. Temp will only get ip to 70. Radiators are barely warm.

Alan (California Radiant) Forbes

Zoning can be done with pumps, zone valves or manifold actuators. You may have one of the last two.

Can you post some pictures of the piping around your boiler and maybe we can figure it out?

GmaChristina

GmaChristina

GmaChristina

GmaChristina

neilc

do you know your water pressure?
18psi for 3rd floor ?

and do you know which valve feeds 3rd floor?
closeup picture of valve body and its indicator

kcopp

Why 78F ? Thermostats are just a switch...not a gas pedal. Turning it up higher wont get you heat faster.
You may need to add pressure to the boiler and you also prob need more baseboard. What is the outdoor temp? The boiler may be set up to modulate its output based on the outside temps.

Alan (California Radiant) Forbes

That green box to the left of the boiler is the interface between the thermostats and zone valves. Yellow light means that the thermostat is calling for heat; red light means that the zone valve is open. All 3 rows should light up when all your thermostats are calling for heat. Do they?

@neilc said to check your pressure.

As far as not heating, do you really need to heat to 78F? Seventy sounds fine, but if you need it warmer, someone will need to change the water temperature settings on the Navien. See instruction on p.62 and on.

https://www.navieninc.com/downloads/ncb-e-manuals-installation-manual-en

Also, the pump is pumping towards the expansion tank which is a problem. Your system should have been piped as shown on page 31. The pump should be pumping away from the expansion tank.

All that green residue on the copper fittings means the plumber didn't wipe the flux off the pipe when he finished soldering. It will eventually eat through the pipe. Have someone clean it off.

All the heating pipes should be insulated.

There should be an air gap on the condensate drain. If it ever clogs, it will back up into the boiler. And is there an acid neutralizer on that drain? See p. 25-27.

GmaChristina

Thank you all. The pressure reads the same for all zones.

All three rows do light up on the boiler interface.

The plumber told us to turn the heat up to 78 on the upstairs thermostat. The rest are set at 72.

neilc

Yes, but what does that pressure read?
you need 18 to reach the 3rd floor

GmaChristina

Around 20 psi

neilc

ok,
zone valve open ?

GmaChristina

Yes. 

neilc

there's still air up there,
and I don't see a good purge there for you,
you would loose the air in the larger (closed) primary loop

the air sep is out of the water loop with that valve closed, and open you have no forced flow to the zones,

try valving off the 2 working zones and forcing flow to 3rd floor

Alan (California Radiant) Forbes

I think @GmaChristina is getting heat upstairs, but not enough to get the room to 78F. She's just doing what the installer said.

Adjust your thermostats to what's comfortable for you and see if the system can maintain the thermostat settings, especially during the coldest nights. If it can't keep up, either the temperature settings need to be changed on the Navien or you need more baseboard.

neilc

GmaChristina said:

Radiators are barely warm.

"Radiators are barely warm"
that's the 3rd floor only, or all zones ?

GmaChristina

Yes on the 3rd floor only. I do believe we did not get the air out of zone 3 because I heard water trickling through last night. We will try bleeding the air out through the radiators again. 

GmaChristina

Thank you Alan. I believe we may still have some air in the line. I heard water trickling so we'll try that again. It's set at 72 but the temp was 69 when we woke up. If flushing the air out doesn't work, we'll try those things.

MatthewPK

Have you tried turning off all zones except for the top floor and letting it run for a day? When you do this do things feel warm?

Does the pipe in the boiler room heading upstairs feel hot?

If you have only one circulator, and a lower floor is open at the same time as the upper floor then the upper floor may get starved for flow since it's much easier for the water to flow through the lower levels than the upper one.

Snowmelt

I think you may have to raise your pressure …. If you run city water up there does it make it up.

hot_rod

pretty unusual primary loop piping:)

Looks like a green handled valve was added to make the secondary flow properly, but the Spirovent doesn't see any flow?

If do you don't have a functioning air purger to get the last air out of the zones. The high loop, 3 rd floor may continue to get air locked or air noise.

It could use a piping correction, move the spirovent down by the loop circulator. Or just add a new one down below.