Combi boilers.

njtommy

I know a lot of guys on here are not a fan of combi boilers do to mainly sizing problems. Either too big for the space heating or too small to produce DHW when size correctly for space heating.

What I find really odd about them is they are designed for smaller/ broom closet installations in my mind, but yet most of them have such large minimum firing rates of 15-20k they don't make much sense to use for smaller houses with out having to add some type of mass to them.

I also stumbled on to this today while looking up some specs on another Weil Mclain boiler.

Still really large but does have a 10-1 TDR. I'm not sure I've seen any combi boilers with 10-1 tdrs yet.
Maybe their is hope for some good combi boilers in the near future.


http://aquabalanceboiler.com

kcopp

They have their place. A condo w 1 bath may not have the room for a boiler and an indirect.
They keep pushing the technology.
Still like the IBC DC.

Paul S_3

looks ok....min firing rate is still kind of high...i have to look more in depth later on....most apartments around me have less than that and i see navien ncb240's installed.....i try not to get involved with closet combi boilers too much ....i see too many improperly sized installed etc etc etc closet installations with numerous problems

njtommy

I just looked up the IBC combi. This is a prime example

IBC DC 23-84 looks to be a nice unit.

Min firing rate 23K.
Max rate is 84 fits a lot of heating needs in colder weather, but on shoulder times it can short cycling the boiler depending on zoneing and type of radiation.

DHW is 2.5 gpm seems a bit low for my DHW needs. Not sure what the temp rise is either but really long cold times I saw 45f cold water supplytemps.

Running the washer, dish washer and a bath tube in my house hold at the same time is very common. Granted it's not for very long period of time, I would say 10mins Max 2.5 gpm just won't do it.

kcopp

Again... not for every application. They do have a unit that goes from 20 to 125.

4Johnpipe

HTP EFT @ 10-1 "Most efficient boiler 2016" by Energy Star
http://www.htproducts.com/EFT_Combination_Wall.html

njtommy

@Paul S NCB240 plenty of hot water, but then still that 18k min firing rate. I looked at the newer NCB-E model hoping for at 10-1 tdr

@kcopp I was really hoping the IBC was something I haven't seen yet and had really low min firing rate of
8-10k.

HTP had a great idea with the gas leak detection sensor in the cabnet.