I have a Nextgen 8 kW boiler. Does anyone know what the third parameter in advanced feature menu does? It isn't mentioned in my user manual. Thank you in advance.

Yes, it is used to derate the heat exchanger unit output. H3 uses the full output rating, H2 derates to 2/3 the full rating, and H1 derates to 1/3 the full rating. So if you have a 12 kW boiler, H2 derates it to a 8 kW boiler and H1 derates it to a 4 kW boiler. This is NOT to be confused with the 1/3 modulation feature (i.e., boiler uses one, two, or all three heating elements) which operates separately and independently of this advanced derate feature. Instead of randomly using all three heating elements, it randomly only uses either one or two heating elements for H1 or H2 respectively. NextGen boilers are extremely well engineered and quite flexible!

Thank you sailawayrb. I have actually used your website in past when designing my floor heating system. Nice of you guys for making that available. So would you recommend getting a larger boiler than the heat load calls for and then derate it to get longer life?

Sure thing and happy you found our HR design software to be useful.

No, this would not be a good idea. Doing this would reduce or eliminate the modulation feature which would negate this beneficial and often needed feature. The NextGen stainless steel heat exchangers are expected to last 15-20 years and cost less than $200 to replace. As in any boiler, actual life is largely a function of the quality of water and the quantity of annual operational hours. So it is best to properly size the boiler for each specific application (i.e., accomplish a proper building heat loss analysis) and use a boiler that is fully rated for the specific application. Furthermore, any replacement heat exchanger must be compliant with the boiler nameplate kW rating in order to meet UL certification and electrical code. As such, it is recommended that any replacement heat exchanger be ordered for the actual full kW rating of the boiler and forgo derating.

I should also add that additional discussion on the NextGen boiler may be found here:

NextGen Boilers

After installing these boilers for about a year now, we highly recommend them. We are also very impressed with their customer service...which is how I originally learned about the subject of your post...we asked similar questions!

Thank you sailawayrb. No need to convince me Nextgen is great electric boiler, saves big $$$ and easy DIY install. I first learned about it on your website so thanks again.

Kind of an odd string of posts here, similar to a one sided conversation,
So for a bit of balance, many electric boilers modulate. Multiple element's come on and off as needed to deliver the required BTU.
Case in point our Thermolec boiler, multiple elements = modulation plus out door reset built in to further refine boiler delivered water temperature based on exterior weather conditions..
Basic electric boiler function.
Dan

I looked at Thermolec and other boilers. My research showed Thermolec to be an inferior product and Nextgen had way more features and benefits:

http://www.nextgenboiler.com/content/features-and-benefits

I went with Nextgen because it saved me the hassle and $$$ of having to design and build a panel that would take up much space and look like a science project. I like that Nextgen integrates everything and automatically cycles the pump during the off season so it doesn’t freeze up. One less thing to worry about. I do wish the user manual was better written but you don’t even need the manual to install it yourself. I see that Blueridge Company sells the cheap Thermolec boilers and expensive panels. So I can see how you would not like Nextgen but I do.

oh boy,
again with the noise,
Not really trying to disparage products or people or there lively hoods,
Just pointing out that there are alternative modulating electric boilers and many manufactures.
Thermolec corporation has been manufacture electrical heating equipment,
modulating controls and steam humidifiers since 1973.
I can assume they enjoy some market share due to there quality.
We have sold Thermolec products for 15 years now, one of the most trouble free products I sell.
Yes we have prefabricated pump panels, free world make your own if you prefer. We design to proper primary secondary systems.
Hanki I am sure Next gen is fantastic and some day they too will have years/decades of sales as well.
I am happy for your purchase as well as your confidence in your product.
Enjoy
Dan