Navies NCB-240/130H Low Heat

[mrpaiken]

I've had a Navien NCB-240/130H combi boiler now for two months. DHW is fine. Two heating zones each with its own circulator pump. The house is only 1,300 square feet.

Zone 2 is fine, but the other, Zone 1, is set for 69 and can't maintain temps more than 65 when the outside temp is below 50. Granted this room has two sliding doors that are old and leaky despite sealing and insulating cracks as much as possible. Regardless the old oil burner kept that room warm except when it would be extremely cold below 20. This morning it was 21 outside and 62 inside that room

The heating water set temp on the navien is maxed out at 180. When I keep an eye on the Navien control panel I can see that the temp mostly hangs out in the 160's but often goes as low as 139 and the unit will sometimes even show itself idle, but with the zone calling for heat and its circulator pump running. Attached pic shows the temp at 140, and the display green, meaning the unit is idle. It dropped a second after the pic to 139 before finally cycling up.

Eventually it will cycle on and slowly go up to high 170's but then cycle down and go down to 150-160 (or lower as I said) before cycling back up. I even mounted an iPhone on a tripod for the better part of a day to shoot a time-lapse vid, and I could see that even though the zone was constantly calling for heat, the temp hung out around 150-160 (occasionally down to 140) rather than 180. The Navien is running pretty much 24/7 and not able to maintain a 69 heat setting for that zone even in moderate outside temps in the 50s. Hardly efficient, let alone "high-efficiency!"

Of the two dip switch panels, the 6-switch unit had (only) number 5 up. My installer suggested switching that down to see if it makes a difference. I have and we'll see if it makes a difference overnight. I've looked online and in my Installation & Operation Manual and can't find any defined function for switches 3-6 so I'm not sure what that switch does or if 3-6 even do anything at all!

I'd love any advice or opinions anyone could offer. Thanks in advance!

 

[jac38]

I've had a Navien NCB-240/130H combi boiler now for two months. DHW is fine. Two heating zones each with its own circulator pump. The house is only 1,300 square feet.

Zone 2 is fine, but the other, Zone 1, is set for 69 and can't maintain temps more than 65 when the outside temp is below 50. Granted this room has two sliding doors that are old and leaky despite sealing and insulating cracks as much as possible. Regardless the old oil burner kept that room warm except when it would be extremely cold below 20. This morning it was 21 outside and 62 inside that room

The heating water set temp on the navien is maxed out at 180. When I keep an eye on the Navien control panel I can see that the temp mostly hangs out in the 160's but often goes as low as 139 and the unit will sometimes even show itself idle, but with the zone calling for heat and its circulator pump running. Attached pic shows the temp at 140, and the display green, meaning the unit is idle. It dropped a second after the pic to 139 before finally cycling up.

Eventually it will cycle on and slowly go up to high 170's but then cycle down and go down to 150-160 (or lower as I said) before cycling back up. I even mounted an iPhone on a tripod for the better part of a day to shoot a time-lapse vid, and I could see that even though the zone was constantly calling for heat, the temp hung out around 150-160 (occasionally down to 140) rather than 180. The Navien is running pretty much 24/7 and not able to maintain a 69 heat setting for that zone even in moderate outside temps in the 50s. Hardly efficient, let alone "high-efficiency!"

Of the two dip switch panels, the 6-switch unit had (only) number 5 up. My installer suggested switching that down to see if it makes a difference. I have and we'll see if it makes a difference overnight. I've looked online and in my Installation & Operation Manual and can't find any defined function for switches 3-6 so I'm not sure what that switch does or if 3-6 even do anything at all!

I'd love any advice or opinions anyone could offer. Thanks in advance!

I've been having the same issue. Not far from you if you're in RI. I'm in Uxbridge, MA

Been having this issue since it was installed 2.5 years ago. Only happens when it gets below 20 degrees out. In general, it was tough to get the boiler to heat up the house over 70 - 71 degrees. Never had this issue with my oil burner.

Installer refuses to contact Navien. He insists that because my pipes drop down to 1/2 pipe, then back up to 3/4 inch pipe to the baseboard that this would be the problem. But, I don't buy that because then my pipes would still be hot/warm. Instead they are cold. Asked several other plumbers if that would cause an issue and they all said no.

I had an HVAC professional come out and he stated that the reason I'm having an issue is that the exhaust pipe is level instead of having a pitch. So any condensation falls back into the system causing it to wait to clear out before it can turn back on again. This would explain why it gets worse the colder it gets outside.

In addition, the exhaust pipe and intake are essentially at the same level. So when exhaust is being blown out, the intake is sucking it back in.

If anyone has answers or can confirm that this is a possibility, I would appreciate it. Tired of my kid eating breakfast in a winter coat because it's 57 degrees the house.

 

[Sponsor]

 

[zebu]

I've been having the same issue. Not far from you if you're in RI. I'm in Uxbridge, MA

Been having this issue since it was installed 2.5 years ago. Only happens when it gets below 20 degrees out. In general, it was tough to get the boiler to heat up the house over 70 - 71 degrees. Never had this issue with my oil burner.

Installer refuses to contact Navien. He insists that because my pipes drop down to 1/2 pipe, then back up to 3/4 inch pipe to the baseboard that this would be the problem. But, I don't buy that because then my pipes would still be hot/warm. Instead they are cold. Asked several other plumbers if that would cause an issue and they all said no.

I had an HVAC professional come out and he stated that the reason I'm having an issue is that the exhaust pipe is level instead of having a pitch. So any condensation falls back into the system causing it to wait to clear out before it can turn back on again. This would explain why it gets worse the colder it gets outside.

In addition, the exhaust pipe and intake are essentially at the same level. So when exhaust is being blown out, the intake is sucking it back in.

If anyone has answers or can confirm that this is a possibility, I would appreciate it. Tired of my kid eating breakfast in a winter coat because it's 57 degrees the house.

I've had a Navien NCB-240/130H combi boiler now for two months. DHW is fine. Two heating zones each with its own circulator pump. The house is only 1,300 square feet.

Zone 2 is fine, but the other, Zone 1, is set for 69 and can't maintain temps more than 65 when the outside temp is below 50. Granted this room has two sliding doors that are old and leaky despite sealing and insulating cracks as much as possible. Regardless the old oil burner kept that room warm except when it would be extremely cold below 20. This morning it was 21 outside and 62 inside that room

The heating water set temp on the navien is maxed out at 180. When I keep an eye on the Navien control panel I can see that the temp mostly hangs out in the 160's but often goes as low as 139 and the unit will sometimes even show itself idle, but with the zone calling for heat and its circulator pump running. Attached pic shows the temp at 140, and the display green, meaning the unit is idle. It dropped a second after the pic to 139 before finally cycling up.

Eventually it will cycle on and slowly go up to high 170's but then cycle down and go down to 150-160 (or lower as I said) before cycling back up. I even mounted an iPhone on a tripod for the better part of a day to shoot a time-lapse vid, and I could see that even though the zone was constantly calling for heat, the temp hung out around 150-160 (occasionally down to 140) rather than 180. The Navien is running pretty much 24/7 and not able to maintain a 69 heat setting for that zone even in moderate outside temps in the 50s. Hardly efficient, let alone "high-efficiency!"

Of the two dip switch panels, the 6-switch unit had (only) number 5 up. My installer suggested switching that down to see if it makes a difference. I have and we'll see if it makes a difference overnight. I've looked online and in my Installation & Operation Manual and can't find any defined function for switches 3-6 so I'm not sure what that switch does or if 3-6 even do anything at all!

I'd love any advice or opinions anyone could offer. Thanks in advance!

1)Two heating zones each with its own circulator pump-is a Navien zone control

I've had a Navien NCB-240/130H combi boiler now for two months. DHW is fine. Two heating zones each with its own circulator pump. The house is only 1,300 square feet.

Zone 2 is fine, but the other, Zone 1, is set for 69 and can't maintain temps more than 65 when the outside temp is below 50. Granted this room has two sliding doors that are old and leaky despite sealing and insulating cracks as much as possible. Regardless the old oil burner kept that room warm except when it would be extremely cold below 20. This morning it was 21 outside and 62 inside that room

The heating water set temp on the navien is maxed out at 180. When I keep an eye on the Navien control panel I can see that the temp mostly hangs out in the 160's but often goes as low as 139 and the unit will sometimes even show itself idle, but with the zone calling for heat and its circulator pump running. Attached pic shows the temp at 140, and the display green, meaning the unit is idle. It dropped a second after the pic to 139 before finally cycling up.

Eventually it will cycle on and slowly go up to high 170's but then cycle down and go down to 150-160 (or lower as I said) before cycling back up. I even mounted an iPhone on a tripod for the better part of a day to shoot a time-lapse vid, and I could see that even though the zone was constantly calling for heat, the temp hung out around 150-160 (occasionally down to 140) rather than 180. The Navien is running pretty much 24/7 and not able to maintain a 69 heat setting for that zone even in moderate outside temps in the 50s. Hardly efficient, let alone "high-efficiency!"

Of the two dip switch panels, the 6-switch unit had (only) number 5 up. My installer suggested switching that down to see if it makes a difference. I have and we'll see if it makes a difference overnight. I've looked online and in my Installation & Operation Manual and can't find any defined function for switches 3-6 so I'm not sure what that switch does or if 3-6 even do anything at all!

I'd love any advice or opinions anyone could offer. Thanks in advance!

I've had a Navien NCB-240/130H combi boiler now for two months. DHW is fine. Two heating zones each with its own circulator pump. The house is only 1,300 square feet.

Zone 2 is fine, but the other, Zone 1, is set for 69 and can't maintain temps more than 65 when the outside temp is below 50. Granted this room has two sliding doors that are old and leaky despite sealing and insulating cracks as much as possible. Regardless the old oil burner kept that room warm except when it would be extremely cold below 20. This morning it was 21 outside and 62 inside that room

The heating water set temp on the navien is maxed out at 180. When I keep an eye on the Navien control panel I can see that the temp mostly hangs out in the 160's but often goes as low as 139 and the unit will sometimes even show itself idle, but with the zone calling for heat and its circulator pump running. Attached pic shows the temp at 140, and the display green, meaning the unit is idle. It dropped a second after the pic to 139 before finally cycling up.

Eventually it will cycle on and slowly go up to high 170's but then cycle down and go down to 150-160 (or lower as I said) before cycling back up. I even mounted an iPhone on a tripod for the better part of a day to shoot a time-lapse vid, and I could see that even though the zone was constantly calling for heat, the temp hung out around 150-160 (occasionally down to 140) rather than 180. The Navien is running pretty much 24/7 and not able to maintain a 69 heat setting for that zone even in moderate outside temps in the 50s. Hardly efficient, let alone "high-efficiency!"

Of the two dip switch panels, the 6-switch unit had (only) number 5 up. My installer suggested switching that down to see if it makes a difference. I have and we'll see if it makes a difference overnight. I've looked online and in my Installation & Operation Manual and can't find any defined function for switches 3-6 so I'm not sure what that switch does or if 3-6 even do anything at all!

I'd love any advice or opinions anyone could offer. Thanks in advance!

"Two heating zones each with its own circulator pump"-is a Navien zone control operating circulator pumps. Parameter setting could be set incorrectly.