De-rating oversized Neotherm

wcs5050

I have a high eff modulating gas Laars Neotherm boiler at a church in that I maintain. … it’s max rate, based on variable combustion/inducer fan is 500k. It’s obscenely large for the load and short cycles like crazy on smallest zone.  

This control has ability to adjust max rate… I turned it down from 5600rpm to 4000rpm (what I’m calling 70% of 500k) and it’s still too big, but behaving better. (Could go lower, bottom is 3000rpm)

I want to tell them I just cut their gas use by around 150k/hr but that might be exaggeration(?)…

Thx for any input

EdTheHeaterMan

Never tell them the high number when talking about savings.

We used to sell a modernization package on old boilers that included a new oil burner, draft control, and vent connector to the chimney base (smoke pipe), combustion chamber, and controls, including the cad cell relay to replace the old stack relay. With the job we could achieve 80% efficiency with no problem. We would guarantee 75% efficiency in the contract. When compared to the 50% and 60% numbers we would get from the pre-1960 oil burners that was a huge savings for half the cost of switching to gas heat. Savee a lot of loyal customers from switching to gas heat over the years.

EDIT:

Another consideration is that by reducing the input, you are also increasing the run time. so the actual gas savings may not be what you think. 500K for 30 minutes per hour is the same as 400k for 37.5 minutes per hour.

Another idea:

Perhaps you could say that the adjustment may have reduced their gas bill. You would be interested to know by how much, so they might compare last year’s gas bills and then keep track of this year’s bills to see if they realize any savings. By asking them for the numbers, you are letting them know that you expect there may be some savings, without stating a specific amount.

wcs5050

Very good points. I never make claims to savings other than in vague terms but was curious here. I was thinking the same thing in regard to looking at gas use against prior year.