Plumber says `Normal Corrosion` - Lochinvar Radiant Heat KBN080

whiskeydecisions

I'm going through the process of purchasing a house and the radiant heat came up as an area of concern. I can't imagine that Lochnivar Radiant heat units have normal corrosion like this (attached image). The home owner had a HVAC specialist inspect said it was completely normal:

LOCHINVAR BOILER-
Boiler is in good working order the corrosion being reported by the home inspector is negligible. This corrosion is very common on Lochinvar boilers. The 4 tapping on the top of the stainless steel heat exchanger have had water seep from threads overtime. This happens due to the different expansion rates of the stainless steel taps versus the brass fittings. Several of the brass fittings have previously been replaced. None of these are active leaks and do no effect the performance or function of the boiler. There is rust in the bottom of the sheetmetal cabinet from a previously clogged drain that was corrected. The boiler currently operates properly and is not effected by any of the issues pointed out by the inspector.


I frankly find it hard to believe the the corrosion has no impact on performance but would welcome insight.
Model: KBN080
Serial: A07H1002447

Zman

I agree that the leaks in and of themselves are fairly normal. The threads may of may not have sealed themselves over time. There may still be an intermittent leak. You are likely not looking at corrosion but just calcium and mineral deposits leftover from the leak. It is puzzling that the someone came to look at the boiler corrosion but did not bother to clean it up and reseal the threads.

My concern on this is not the corrosion damage effecting performance. My concern is that this boiler has likely never been serviced at all. There should be an annual maintenance schedule in the owner manual. This maintenance should have included not only fixing leaks like these, but should also include opening the boiler, cleaning the heat exchanger and performing a combustion analysis.

Imagine going to purchase a used car with 100,000 miles. Would you be concerned with oil stains around the transmission seals? What if the same car with the oil stains had no service records? No evidence of 30K, 60k 90k service or even an oil change?

Lochinvar is a solid boiler. This boiler probably just needs a thorough cleaning (inside and out) and combustion analysis. I would be surprised if the condition of this boiler turns out to be a deal killer on a home sale.

Just like a used car example, download the manual, ask for the service records and negotiate the price based on the service history.

whiskeydecisions

Zman, thank you! Your insight is on point and appreciated.

Ironman

Whenever there's a leak on a system, fresh water, with fresh minerals, is added to the system. Those minerals become bound to the heat exchanger and hinder heat transmission from the burner to the water. I totally agree with Zman about a complete cleaning and servicing on both th fire and WATER side of the boiler.

Both Fernox and Rhomar offer chemical cleaners that will clean the inside of the system and de-scale the heat exchanger.

JUGHNE

Also, just to point out to the OP that the system should always be under pressure of 12-15 PSI. If any of the suspicious areas were still leaking they would be wet.

A simple test would be to shut off the city water supply and observe if the pressure drops on the gauge.

HomerJSmith

All corrosion is natural. It is a confluence of factors. The question is--is it desirable and what does it mean.

Corrosion on a car battery, for instance, will leak current across the + and - poles and could inhibit current to the starter. That's undesirable if one is intent on keeping a charge and starting the engine.

What I suspect from looking at your photos is that you have hard water in your system, which is greater concern to me as there can be calcification of the heat exchanger. 1mm of calcification on the walls of the heat exchanger will reduce heat transfer across the heat exchanger 12%. This can cause more serious problems with the HX with inability of heat moving from the gaseous flame to the water resulting in failures of the HX . If so, I would drain the sys and clean the sys and fix the leaks and fill the sys with good water.

This is an older Lochinvar and may need the heat exchanger cleaned in the combustion chamber (different than my suggestion above) and a proper combustion analysis done with a recently calibrated meter. As suggested by Zman, above.

Robert O'Brien

https://www.consumerreports.org/boilers/lochinvar-recalls-residential-condensing-boilers/

HomerJSmith

Robert, I think the recall is for a Fire Tube boiler. Whiskeydecisions, has a Water Tube boiler. Thanks for the heads up.

Alan (California Radiant) Forbes

Thanks for that recall information, Robert. Not a peep from my Lochinvar wholesaler.