ray boiler and heatloss calcs

Tom Hopkins

I think properly sizing modulating boilers is still very important to two reasons:

1. Matching the heat loss of the building allows greater turndown and therefore betters efficiency. If the heat loss is 100,000 Btu's and you install a 200,000 Btu boiler with 5:1 turndown the lowest input that unit will modulate to is 40,000 Btu’s, which is only 2.5:1 turndown on a 100,000 Btu heat loss. The 100,000 Btu unit with 5:1 will throttle down to 20,000 input for less cycling and better efficiency.

2. A 100,000 btu boiler usually costs less than a 200,000 btu boiler, so if you take the time to do the math and quote a smaller unit that costs you less, your price to the HO may be much lower than someone who guesses the size and goes with an oversize unit. I think there's more potential to loose the job on price than by having the HO shop the calcs.

I can do a heat loss in less than an hour in most places, so to me it’s not a real big time issue.

Charlie from wmass

the Ray boiler had me thinking

and sometimes that is a bad thing, sometimes. The idea is that These new boilers seem to be made for folks who do not want to do more than a guestimate heatloss. I think Utica has the same idea of making one boiler in a mod/con configuration then letting the boiler adjust to the load instead of the contractor taking the time for a proper heat loss calculation. WHat do you say when you install one opf these boilers when asked for a heat loss before you start? I have gotten into the habit of doing heat losses but I do not release them unless I get the job. also at that time I do a more acurate one for tuning in the system. The free estimate is still alive and well in my area of the state at least and with the slow down it seems to be gaining new life. ALso if anyone has installed a Ray boiler I would like any feed back thanks guys.

Unknown

Free estimates

IMO can work against you too. Doing a HL usually(as you know) is very time consuming, only to have the HO "peddle-it" to other contractors after you doing all the #s work.
I think Timco has installed a Ray, although I have not seen him here lately.

Dave

Charlie from wmass

I know they are important.

It is just some boiler manufactures are not giving an sizes to choose. I realize the major players do offer more choices. it was the Ray that got me thinking then I saw the Utica 95.

lownox

I like...

...how you say "only 2.5:1 turndown"

Seems to me that 100mbh to 40mbh would be just fine. Of course, I just being nit-picky.

lownox

The utica is a mono-block design and likely wouldn't be released at a reduced input. They would have to redesign the burner side to achieve equal turndown. The cost incentive wouldn't be there IMO.

The RAY is 2 end sections of a KN series boiler. Again... to get equal turndown the burner side needs a redesign for lower inputs with the same turndown. I don't see Mestek making a smaller RAY... they don't have a boiler section small enough. Somewhere between the GS-110 section and a KN section...

Just my 2 cents...

I never really thought about it in terms of doing a HL calc or not.