Lochinvar KHN199 Blower Replacement - again.

acruxksa

Hi All,

Just looking for any information that might help troubleshoot a perceived issue. Woke up to no hot water this morning and the boiler was in lockout. Reset didn't work, so I called for help. Didn't take long for the tech to isolate the problem to the blower. It's been replaced and everything is up and running again.

The problem is that counting the original blower, this is the third blower in 18 months. The boiler was installed in late September of 2017 and the original blower failed catastrophically in early February 2018 (February 6th to be exact). I say catastrophically, because the plastic blower literally disintegrated on the motor shaft. Fast forward to this morning, March 27th 2019 and again the blower/motor has failed. I wasn't on site for this one, so I can't exactly say whether it was the motor or blower, but since they seem to be replaced as an assembly, it's still a relatively new part.

Lochinvar's warranty is 5yrs so I'm not too concerned about that, however it seems like this is going to be an ongoing issue and that does have me concerned. Should I just chalk this up to bad luck, or is there something else that could be causing this?

Leon82

How does it terminate from the building?

That seems to indicate it is sucking in it's exhaust

acruxksa

I'll have to check that when I get home, had to fly out to work this morning so it'll be a couple weeks. Original installation was done when house was built in 2007 for a Munchkin boiler. We purchased the house in 2017 and the Lochinvar was installed to replace the Munchkin as part of the sale. I have wondered about the intake and exhaust pipe routing, but don't really know much about it. I can say both run about 6' vertically up from the boiler to the ceiling before running about 16' horizontally to exit the house on the East side. Both are PVC and although I don't know their exact dimensions, they are both larger and reduced near the boiler. They have done combustion testing on the boiler and it's within spec.

The exhaust at the side of the house looks like a typical direct vent fixture, but I haven't paid much attention to the intake. I will have my wife take pictures of that area when she gets home from work.

acruxksa

Here's a picture of the boilers exhaust. I can't find an intake anywhere, so I'm guessing it's in the stainless box to the right of the exhaust??????

Zman

That type pulls intake from the perimeter on the back side. They usually work pretty well. Are there any building projections near by.

Gary Jansen_4

That looks like 2"pvc.
199 should be 3" pvc.
In my opinion, that's a horrible vent termination, and is likely your problem

bob eck

Can you pull fresh air from another location? If you can see how long the blower lasts that way.
If you are going through blowers every 9 months then I would say you are bringing in exhaust gas and not 100% fresh air.

Zman

Gary Jansen_4 said:

That looks like 2"pvc.

199 should be 3" pvc.

In my opinion, that's a horrible vent termination, and is likely your problem

Good catch! that is probably the issue.
If you cannot replace the pipe, you may be able to limit the output of the boiler. I have seen lochinvar tech support do that on problem installs. Very few homes need anywhere near 199,000.

acruxksa

Thanks for the pointers guys. I'm pretty sure it's 3"pvc for the exhaust and intake, but the intake is reduced at the boiler. Should it not be reduced?. This wall is on the East side of the house and there are no projections within 20' of the vent. After studying this, I thinking I should pull the cover off and make sure nothing is blocking the intake. If there are no blockages, I will look at possibly moving it.

It certainly seems like an ongoing issue, although the previous two blowers failed differently. The first one failed when the plastic blower fan broke off the shaft. The most recent one failed when the motor died.

Also, I'm pretty sure a 165K btu boiler would be plenty, but this is what came with the house (6000sq ft built in 2007). I believe the put the 199K btu boiler in because that's the max btu's the indirect tank can handle, coupled with the 50Kbtu heat exchanger for the heated sidewalk.

Here is a black and white security camera pic of the boiler intake/exhaust piping.

Leon82

You can fix that by venting like the book says with 2 90s and an approximate 12 inch pipe.

The intake turns down with a 90

Ex 90 up then 90 back to horizontal and if I recall 12-15 inch centerline distance

DZoro

Not a big fan of that termination style. In low fire the exhaust velocity is real low and slow. That allows the exhaust fumes to "hang around" thus reinjecting back into the boiler. I'm sure that boiler probably spends most of its time in low fire, and causing some of your issues.
Terminate with 2 separate pipes, exhaust 18" above the intake, will do the trick
D

clammy

If u look at htp installation on that v1000 vent I believe they recommend a 12 inch piece of pipe in the outlet of that vent termination .when I did use them I added a 1 ft piece and had no recirc issue but I have seen them installed w out and in bad location and have had blowers go . I would make sure that the discharge is in the correct place had a siding guy reverse one when they resided when they called that the heat was out I just happened to chk the vent and found it reversed but after 1 1/2 years the blower was shot and until I replaced there where intermittent control issues . Those blowers are goin from exhaust recirc have a 12 inch piece of pipe added and have the unit put in test mode and put the cover on the unit and have them chk for recirc gases in the fresh air inlet . Hope this help I have the same termination on my munchkin 13 years same blower motor peace and good luck clammy

clammy

I also think that termination is to close to the ground unless u get no snow ,I would think that outlet pipe should be snorkel up above snow line

acruxksa

Thank You All for your advice. Yes my boiler spend a lot of time on "low fire" I've got a lot of ramp delay and it rarely if ever gets above about %70 fire rate and even then only for a few minutes here or there.

We do get quite a bit of snow, so I will look into having the vent/intake separated and raised as everyone has suggested.

Again,
Thank You! This place has given me tons of great advice. I can't always follow it, but do try whenever practical.