ScagDriver1037
New Member
Hi All!
I am attempting to troubleshoot why my Navien NHB-110 boiler howls during higher demand calls for heat from multiple zones at the same time. The 2800 sqft house has 3 floors and 5 different heating zones. The unit pulls air intake from outside and exhausts outside. The unit also has an outside ambient temperature sensor. The circulating pump that sucks water into the boiler is a 3 speed taco 0015-msf3-ifc set to the middle speed. the noise exists at both middle speed and high speed. The boiler uses propane gas that is regulated down to 7-11 inches water column. The cold boiler pressure is around 12 psi and the hot boiler pressure is around 18-20 psi @ 180 degrees F. It is noted that the propane line supplying the boiler consists of approximately 50 feet of 1" black steel pipe and 6 feet of 3/4" CSST pipe connected between the boiler and low pressure regulator.
I have purged the air out of all 5 zones. I have performed the annual maintenance on the boiler such as cleaning fresh air intake mesh screen, drained/cleaned the condensate trap, cleaned the in-line water strainer, and descaled the unit for 60 minutes using nucalgon vital flo descaler.
The boiler is located in the basement and the howling is loud enough that it can sometimes be heard on the second floor.
I have attached videos of the howling and pictures of the boiler and 5 zone manifold.
I do believe the noise is purely related to the boiler as the noise is definitely coming from within its appliance shell. The noise is there whether the front cover is on or off which makes me think it is not a air intake question or a faulty front housing cover gasket.
I appreciate any thoughts on what I could try…
Thanks!
I am attempting to troubleshoot why my Navien NHB-110 boiler howls during higher demand calls for heat from multiple zones at the same time. The 2800 sqft house has 3 floors and 5 different heating zones. The unit pulls air intake from outside and exhausts outside. The unit also has an outside ambient temperature sensor. The circulating pump that sucks water into the boiler is a 3 speed taco 0015-msf3-ifc set to the middle speed. the noise exists at both middle speed and high speed. The boiler uses propane gas that is regulated down to 7-11 inches water column. The cold boiler pressure is around 12 psi and the hot boiler pressure is around 18-20 psi @ 180 degrees F. It is noted that the propane line supplying the boiler consists of approximately 50 feet of 1" black steel pipe and 6 feet of 3/4" CSST pipe connected between the boiler and low pressure regulator.
I have purged the air out of all 5 zones. I have performed the annual maintenance on the boiler such as cleaning fresh air intake mesh screen, drained/cleaned the condensate trap, cleaned the in-line water strainer, and descaled the unit for 60 minutes using nucalgon vital flo descaler.
The boiler is located in the basement and the howling is loud enough that it can sometimes be heard on the second floor.
I have attached videos of the howling and pictures of the boiler and 5 zone manifold.
I do believe the noise is purely related to the boiler as the noise is definitely coming from within its appliance shell. The noise is there whether the front cover is on or off which makes me think it is not a air intake question or a faulty front housing cover gasket.
I appreciate any thoughts on what I could try…
Thanks!
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