Improve Efficiency, to reduce fuel costs
This is my setup at home installed two years ago
Biasi B-4, direct vented.
Beckett NX w/ .6gph 60deg nozzle
Honeywell R7148P Rev 5
Bock 40Gal indirect DHW, T-stat set at 120
All Zones Controlled with Taco "00" Circulators
Zone one w/ pri, DHW
Zone two, first floor radiators on a loop.
Zone three, not active, a loop for a FirstCo. HydroAir Handler.
I was looking at the Becket Heat Manager or an Outdoor Reset to improve efficiency of the system. Currently the low temp on the biasi is 150deg. and high limit is 170. The Becket NX burner has a 45sec pre-purge and set to 4min post purge. When there is a call or heat from the DHW it cycles and the boiler will sit at 170 for hours, and when there is a call for heat the boiler is already at 170 but due to the system the burner fires and the circulator for zone 2 turn on and a heat cycle is completed etc..
It seems to me the Heat Manager wold be beneficial in my case as the circulator could be turned on without the need for the burner to fire.
I also had the idea if it is possible to for lack of a better word have something installed for a post-purge cycle for the circulator pump, after a call for heat is satisfied the circulators would continue to run for xx time. I know Taco makes a SR503-ext that has a plug in module to accomplish this but I'd like to know if there are alternatives that are available that can be installed by a HVAC Pro rather than buying and having a new Taco zone controller installed just to add this function.
Another idea is to somehow capture the heat going thru the direct vent from the boiler to recapture some of the heat being pumped outside and reuse it in a way to improve reduce the call for heat from DHW if this is even feasible, it just seems that rather than just sending the waste heat outside it could somehow be used sort of like a hydro air system. Are there any products that exist to accomplish this?
I'm also planing on insulating the basement walls with 2" foam board to reduce heat loss thru the basement walls.
Can anyone offer any suggestions as to my quest for better efficiency. So I can speak with a local HVAC person more knowledgeably about what services I'd like.
If this isn't the correct place to be asking for help/info like this could someone point me to the proper or more appropriate forum
Thanks in Advance
There are some fans of the Beckett heat manager on this site. I'm not one of them.
I prefer a true OD reset control.
On DHW calls, both the heat manager, and OD reset control allow the boiler to go to full temp, to have the ability to maintain both high usage ability, and quick recovery the indirect.
It would keep the burner off if you got a heat call imediately afterward though.
Insulation is good. Any where you can improve the insulation will help, attic, etc. Also, see if you can decrease the amount of fresh air coming into the house. This will save you more then a reset control or heat manager.
The sizes of your equipment tell me that you dont have a large heat loss to begin with. A .6 nozzle equates to 84000 btuh input. This is probably sized for the first hour recovery rate of the indirect water heater. taking too much heat out of your exhaust will cause condensation. Can your boiler handle this? if not, prepare to buy another one. The heat manager does work. it simply creates a bigger span than the aquastat gives you to cause longer run times on the boiler when it is enabled. The longer run times will give you better overall efficiency. All that being said, it seems like you have a pretty good setup that may just need a bit of tweaking. Hire a pro. clean the boiler, perform combustion analysis.
I tink the NX burners pump pressure is 150PSI.
That brings that nozzles output up to about a .73
Or just over 100,000 BTU input.
Yes the Beckett NX runs at 145PSI, and the nozzle output is effectively .71gph,
Initially I was told I only needed the Biasi B-3, but we decided on the B-4 Because of the planned 2nd floor expansion. Also do I really need Zone 1 to be priority, it seems as if my system is quite capable of handling the demand of all 3 Zones at once. Or does that negate the initial goal of becoming more efficient ??
So far the general consensus is that I should insulate.
On high DHW demands, priority will keep you from losing your hot water.
You might be able to get away with it disabled until the third zone in hooked.
But, priority doesn't make the boiler more efficient. Just helps to prevent losing hot water in the middle of a shower.
all the biasi boiler i have installed have been cold start no low limit as far as making the boiler more efficent you could re pipe it primary secondary use a outdoor reset control modulate water temp going to the radiation and run circ on heat zones constant you could also get a control to make the indirect a dump zone when boiler fires to the limit it will run the circ for the indirect after a call for heat so you are not getting as much stand by loss but you would have to install a thermostatic mixing valve on the indirect because the tank temp will be higher then the aqua stat setting also dont try removing more heat from the flue if its oil youre trying to save add a small wood or pellet boiler into the loop and use the oil as back up