Lochinvar Knight LCD & Rotart Encoder Knob Failing

BigRob

Anybody else seen the pixels on a Lochinvar LCD display malfunctioning? There are about 10 areas where the pixels are stuck activated. It's almost unusable. Also, the rotary encoder is getting flakey. These have been the only issues with the unit. It's been a workhorse heating a 50 gallon indirect in a 12 condo building since 2010. The exhaust outlet temp and water outlet temp are still within spec, so I've never cleaned the HX. Very happy, overall. If it ever dies I will switch to a Lochinvar water heater vs a boiler. In SF I have to get boiler inspections, but not water heater heater inspections, even though they are essentially the same thing now. I think the industry should address this, somehow.

-Ched

delta T

BigRob said:

The exhaust outlet temp and water outlet temp are still within spec, so I've never cleaned the HX.

-Ched

This has nothing to do with whether you should clean the heat excahanger or not. It is required maintenance every year. Since it is only heating DHW you might be okay with every two years, but ten, I would get someone in there to clean it right away. You may have already significantly shortened it's life, but don't let it go any longer.

As to the display, you can order a new display board to replace it. Pretty easy to swap out.

BigRob

I'll take a look at it soon.

I've been operating it based on Lochinvar's guidance in the service manual, but I'm now curious what it looks like in the HX.

RPK

The older manuals do say something to that effect. Until water temp and outlet temp get too far apart, heat exchanger cleaning is not necessary. The newer manuals don’t say this anymore and it’s common practice to clean them (at least) annually regardless of what the manual says.

I used to do maintenance on a building that had a Lochinvar Knight and 3 Lochinvar Shield water heaters. We maintained the Knight and cleaned it every year. At some point we determined that no one was maintaining the Shield water heaters. (I thought they had the plumber taking care of them, we only installed the HVAC equipment) They had been installed for 6-7 years (without issue) when I cracked one open for the first time. They weren’t nearly as bad as I expected, but the debris was really hard and baked on. Thank god for the Lochinvar heat exchanger cleaner tool (drill attachment). I’m sure results will vary, and must depend partially on what happens to be in your combustion air. Had the same thing happen on a number of commercial buildings. Seems the plumbers around here aren’t in the habit of offering preventative maintenance when closing out jobs. Eventually we wised up and starting adding water heaters to our equipment list from the start instead of a few years too late.