New boiler won’t heat house

Dcaddaleen

Last year we had our old Munchkin gas boiler replaced with a Navien NHB-150. Soon after the install it was clear that the system was not able to heat the house as well as the Munchkin. On days with temperatures in the 20 degree Fahrenheit range my main floor struggles to get over 68 degrees. This was never a problem before, even in much colder outside temps. 

The company that installed it has been out a number of times, the first thing they did was change the boiler to the max heat setting. The boiler runs at 178 degrees generally. This did help but did not solve the problem. 

I think the system is plumbed incorrectly. I think return is getting mixed with supply and causing the base board units to not reach peak temp. 

I have attached some photos of the system and would greatly appreciate your thoughts. I am new to boiler systems and the HVAC company is not instilling a lot of confidence that they know what they are doing. Let me know if you see other things that are concerning. Thanks

Dcaddaleen

Here are some additional photos. I have four zones, three for space heating and one for heating my hot water in a holding tank.

EdTheHeaterMan

Agree. there is an extra primary/secondary desigh that is missing a circulator. Get the installer back to fix it. The extra Primary Secondary loop is not necessary By removing the pipe replacing the closely spaced tees with elbows will fix the problem.

This repipe will fix the problem.

.

But the air scoop is in the wrong place.


If your contract says anything like "installed in accordance with the manufactures instructions", then your contractor is in breach of contract. He didn't follow the instructions. And where is the Expansion tank? This diagram mau help your contractor to understand his error.

Matt_67

What Ed said.

Dcaddaleen

Thanks Ed and Matt. I appreciate the quick response and feedback!

hot_rod

It could, should be this simple. It's not a great air eliminator, worse when mis-installed.
Maybe upgrade to a micro bubble type, Caleffi Discal for example

Ahomeowner

If your contract says anything like "installed in accordance with the manufactures instructions", then your contractor is in breach of contract. He didn't follow the instructions. 

Also, code requires that all materials be installed according to the manufacturers instructions.  I have noticed that many contractors do not ever read the manufactures’ installation instructions, which is mind-boggling! Warranties may even depend on it (I’m referring to all materials, not just heating equipment.)  I wonder whether it may be worth it to get a fresh set of eyes to come out and make the corrections and look over the entire install.

Dcaddaleen

Thanks everyone!