Knight cleaning

Larry (from OSHA)

It’s been one year since installing this Knight 80 which is attached to three fintube baseboard zones and an indirect. Operation has been flawless and about 30% less fuel used degree day adjusted.

Following the service manual instructions, the burner was cleaned with compressed air with no visible dust being blown off. A couple of insects were toasted on the inside of the burner.

The HX had a small amount of the usual coffee ground type debris which was vacuumed out. Using hot water only, the HX was cleaned off and the space between the tubes got the credit card treatment followed by lots of plain water flushing. Condensate trap was cleaned to get the crud that washed into it. Both the igniter and flame sense rod had a very light coating which was lightly sanded off. The replacement igniter, flame rod and gaskets will remain as spare parts on the shelf.

There are some stains that remain on the HX and I don’t know if chemical cleaning would have taken them off, but the factory doesn’t specify any so I didn’t use any. I can see where prolonged contact (several years) with the coffee crud could possibly lead to surface pitting.

The last part of the cleaning was the water side flush which resulted in a minuscule amount of debris.

Lochinvar has a service schedule of 10,000 running hours or 10,000 ignitions. After one season, run time is nowhere near with only 3718 hours firing. There have been 9855 ignitions, so it was getting close from that perspective. Interestingly, the factory only requires HX cleaning when the exhaust temp is more than 54 degrees hotter than the inlet water. Mine was nowhere near that. The one thing left to do is a combustion check.

By the way, a big thanks to Kal for the heads up on the recent service tip regarding the igniter and sense rod lead connectors.

Larry

Mike2

Great Post

l

Mike2

Great Post....

Hi Larry..

My fingers got too far ahead of me and I had an email composed but lost it..

Great post on the cleaning and great pictures...

Regarding the material that you found inside the combustion chamber that you referred to as "COFFEE GROUNDS"...

Do you have any idea or have you read anywhere what the composition of those coffee grounds are? Do you think they are from the Natural gas or the incoming air? You also spoke briefly about pitting. Did you physically see some pitting occuring on the tubing?

Regarding the inspection, did you have to replace any parts such as the target wall, the gasket, or just lightly cleaned the flame rod assembly?

Great Job... Thanks
Regards Alex

tim smith

My take on the coffee grounds in stainless heat xrs

I seem to remember hearing they are some sort of a by product of chemical reaction between the chemicals in natural gas and the stainless steel. Maybe iron oxide of some sort. ?? for Larry, looks like you are having somewhere around 3 cph of operation. Just wondering what all think of that #. High, low?? Thanks, Tim
PS, I think the 10K hours of operation between cleaning is way to high for this heat x design, the Munchkin could never make it that long with out shut down...

Brad White_200

Coffee Grounds

Recently cleaning our Vitodens, what was in the bottom was almost a charcoal, gritty debris. OK, maybe coffee grounds. I took this as being burned organic material sucked in via the combustion air intake.

Pollen, grass, bugs, small animals...

The remainder of the SS was reasonably clean but had that brownish-tan staining, to which Citri-Surf 3050 was applied with a nylon brush and yes, what a great time to cut up the HD credit card .

No solids anywhere but at the bottom of the chamber.

tim smith

Brad, I don't think the material is organic, otherwise I would

see this in all the other high eff equipment w/ sealed combustion we see. My guess!! It would be interesting to take to a lab to find out what it is??
PS, Just got my TT prestige w/ indirect up and running on my house after 20 yrs dealing with scorched air,albeit high efficiency :O. Now have radiant floor in my liv/din room area with study, kitch and main flr bed to do yet and upstairs rads but what a difference!! Dang I am stupid for waiting this long. Tim

Brad White_200

Congratulations

on the move to hydronic.

"Throw away those crutches, Brother Tim! Arise! Hallelujah! You have crawled for too long, now you will WALK! Yeah, verily, you are gonna RIDE on the train to Glory!

Amen

tim smith

I did get baptised when I fired off my boiler. Started filling

and did not check my fill valve bypass and it was in bypass position and I had not ran my relief line to floor yet, boosh, shot all over me and my work bench.

Brad White_200

Don't feel badly,

When I was air pressure testing a new section of piping years ago, I released a valve to vent the air. Instead or in addition, I heard a long whooshing sound, like a torpedo launch.

I almost wish it was.

The air charge had found a large slug of water in a 1.25" iron pipe and launched a bolus of inky black water out an open radiator feed, all over my office. Ceiling, walls, floors, windows, 'puter,...

Total re-painting and salvaged the hard drive...

Then there was the "I forgot to isolate a Runtal wall panel radiator" incident. The groan is best described as "Crush Depth in Das Boot". Turned my Runtal into a mattress with double the water volume. Still heats, looks, well, chubby.

I think you are ahead!

Paul Rohrs_4

Bolus

Webster: A soft roundish mass or lump,esp. of chewed food.

Good word usage: I'll take "Mechanical Room Cleanup" for $400.00 Alex!

Regards,

PR

EBEBRATT-Ed

Brad, your post reminded me of a ground water heat pump loop we did about 10 years ago. The well contractor did the digging and installed all the pvc in ground for a closed loop. They installed the loop and pressure tested it. Apparently some ground water got into the piping as they were assembling it. It sat for a month or so pressure tested while all the inside work was being done. A rookie working for the well contractor took apart a pvc ball valve union and didn't realize the valve wouldnt hold pressure with the outlet side union disconnected. The guts of the valve blew out under 100 psi test pressure and carried with it into the building all that stagnent ground water that was lurking in the pipe. The smell was absolutley wretching-we had to leave the building-like falling into a septic tank!

And I thought I was the only one that did stupid stuff!
Ed

Larry (from OSHA)

Alex and Tim

I don't know what the coffee grounds like stuff is. I suspect it is a combination of both air and gas contaminants that precipitate out during combustion.

As far as pitting, I did not see anything that appears to have actually compromised the surface of the HX. My uneducated guess is that if this stuff was left in place for a long time, it might lead to some corrosion, but again, just a guess.

I did not replace any parts, but I've got them if I need them.

Tim, the recommended time frame for service/cleaning seems high to me too. I believe that the Munchkin HX is the very same one. The major difference between them is the way they deal with the sealed combustion.

As far as the hours of operation, one aspect that I think is noteworthy is the number of hours operating below 50% output. This unit ran 2128 hours under 50% and 848 hours above. There were 744 hours of domestic hot water production. During the shoulder seasons, a single zone will call and not be able to shed the minimum output of the boiler. Hence the cycling. Not perfect, but not too bad either.

Larry