Lochnivar KHN155 Boiler for Hydronic floor heating in 2 story + basement + garage + driveway

griam01

We recently purchased a home that has radiant floor heat via pex and a Lochnivar KHN155 Boiler. We are in the northeast and it seems that the boiler is not keeping up or having issues. It is located in the basement and there are 6 zones. 3 zones for each bedroom, 1 zone for main living area (family room, kitchen, dining, office), 1 zone for basement and 1 for garage and driveway. 1 of the bedrooms is on the main floor, the other 2 are on the 2nd floor. We did have someone come take a look and said that they did maintenance and that the system was low on water (house did sit empty for about a year), so he lifted the valve so there was pressure in the system and said that the automatic water flow is now working (he claimed it may have been temporarily stuck). He also cleaned out the condensate trap and said that was also an issue. Although after he was done, it did heat up after several hours (expected, I know it isn't instant) and seemed to hold for a few days, but now that it is colder 20s or teens at night the temperature is dropping in the house. Sometimes we check the boiler and see that it has the error too many recycles and it goes into lockout and we have to reset it. Looking for advice on what to check/look for. The house was built in 2018, so it isn't very old unit. Thank in advance for your time and let me know any other information I should provide to assist.

Ignore the time and date the power had gone out and reset the time and date I just reset it after I took the pic

also including a link to a video showing it’s startup and what it does you can hear like a fog horn noise as well

https://share.icloud.com/photos/0a22npe9TVtbqGQ_PEcF8kWfQ

hot_rod

I suspect you have an air bubble somewhere preventing adequate flow.

If it was low on pressure and it got boosted you probably need to purge the boiler and distribution.

A sealed system should not loss much if any pressure. Confirm there in not a slow leak somewhere.

Close the fill valve and watch the pressure gauge over a few hours or overnight.

JUGHNE

Can you post still pictures of the piping around the boiler?

With drive way heating you may have glycol (antifreeze fluid) in the system.

If you purge the whole system with raw water that may be an issue unless you have a heat exchanger for the driveway and perhaps the garage.

DCContrarian

If it was turned off for a year it could have frozen.

If it didn't freeze, it was either drained or it has glycol. If it had glycol, filling it with water wasn't the right thing to do. Systems with glycol should always have the fill valve shut off, I like to take the handle off and hide it.

If it was drained, any air in it has to be purged, simply opening the fill valve isn't enough.

If it froze it may now be leaking.

griam01

here is a picture of the left side. This is the only side where there is anything.

here are some additional pictures of everything connected.

hot_rod

Personally, I would not put a fill valve on a system that has or will have glycol. A fill unit or glycol PIG is a better option.

griam01

we had the hvac guy here and he said there is not glycol in there at all.

GGross

The glycol will be on the driveway side of the flat plate heat exchanger shown in the pic. You have had a leak on your boiler side air separator for starters, a small leak even when no water is visible can drop the pressure in the system rather quickly. It's better to fix the leak than to keep an open fill valve though sometimes you just need to get through a season. Fresh water will introduce fresh minerals and air into your system lowering the life of pretty much all the components. What temp is the boiler set to fire at? the error says the outdoor sensor is open, assuming the boiler can't see it the temp may be calling to high for your heating system if its all in floor radiant

The pumping strategy seems a bit weird to me as well? 2 pumps one on the return of the boiler, one on the supply, and no primary/secondary, seems a bit weird unless I am just seeing this wrong, almost like they meant to pipe it primary secondary but missed a step. Does the big B&G pump just pump straight at a tee that splits off to each manifold there or is the piping different than that?

griam01

Thank you @GGross this is all new to us. It’s set to fire at 125 degrees. It also seems we do not have an outdoor sensor that could be found outside.

The driveway was added on after the fact. It was not part of the original design we found out from the hvac company that came out. Apparently they told the original homeowner to do a separate boiler for it and he found another company to do it. So I am not sure what the thought is there.