Oil Hot Water - novice question

[Got Wood]

Hello - First time in the "boiler room". I started to use the search engine and got side tracked, I realize this is probably very elementary so excuse me....

I have oil heat in the house which also provides hot water. Last year I started burning wood for heat through the FPX 44 and have acheived great results with it. After completing a full year I saw my oil consumption drop dramatically. However, I still feel it was too much to provide a backup source of heat (rarely comes on to provide heat) and hot water.

I do not have a separate or "spare" HW tank.

My Oil burner seems to kick on frequently and run for very short periods. I'm assuming it is working at keeping the HW at the minimum heat.

So, I'm beginning to think of ways to improve yet I am pretty uneducated.

First thought, is there any "low hanging fruit"? Things I can check or do that require little effort or cost that could improve efficiency (other than perhaps kicking my 3 teenagers out of the house and reducing shower time).

Longer term. What are the potential options to invest in order to improve efficiency - associated with that, how much more efficient are we talking? Thinking about pay back period. If they improvement is drastic and the investment is low then it may be worth it and visa versa.

I realise there are probably a ton of variables required in order to provide an answer. What I am hoping to get is direction here.... things to consider, ideas, etc...

I'd appreciate any insight you can provide. Thanks.

 

[ohbie1]

My Oil burner seems to kick on frequently and run for very short periods. I'm assuming it is working at keeping the HW at the minimum heat.

One thing you can do for free is to look at your aquastat. (this is usually behind a cover (possibly Honeywell) that is attached to what looks like a pipe going into the boiler. There is a HI and Low limit setting. You might want to adjust this to low=140 °F , and Hi=180 °F . If not already set this way, it should make the burner run a little longer but less frequently.

 

[R Mannino]

I'm guessing that you have a tankless coil for hot water. Which means that the aquastat used with your boiler is designed to maintain a certain temperature. This is why it cycles periodically, to maintain that temperature. Your probably going to have to rethink your strategy on how you make domestic hot water.

 

[Dune]

For you, the lowest hanging fruit would be a solar water heater so you wouldn't have to burn oil for 7-8 months a year. There are many sites which take you through the whole process DIY, or if you are not that type, now is a pretty good time to pay a pro, since there are big rebates available. The next step, heating your DHW with your fireplace insert is much higher hanging, after you figure out the solar install, it should be within your reach.

 

[jimmy dean]

If as suggested in the previous post you have a "standby" boiler - keeps a warm core of water year around. If so you have choices some easy (less expensive) some not so easy... If you have more than one zone for heat ( two or more thermostats) your quick solution would be add a loop for a "indirect fired" hot water tank. This would allow you to disable your direct -in-the -boiler coil and the boiler would only come on -woodstove running- when the indirect tank calls for heat to heat your hot water. If you have only one zone you can have your existing boiler converted to on-demand with the indirect hot water heater as above. OR, should you have a unused flue, or are willing to add a flue, install a 40 gal oil fired stand alone hot water heater. Otherwise you live with what you have. Good Luck

 

[mikeyny]

welcone to the boiler room.There is a lot of great info here. Some real simple and some stuff way above my head. I would say to keep it as simple as possible. Set your aquastat down about 20 degrees. If you mostly use it for hot water it will save a bit of money. As for those teens, that's a whole nuther problem. I have raised a half dozen plus one. 14 yrs ago I had the problem of teenagers staying in the shower too long. So instead of wrestling a soaped up kid out of the shower I put a timer on the hot water going to that shower. I set the timer up for 8 mins, start to finish. Saved a ton of money. It's fun to hear it tic tic tic and then snap, off goes the hot water, but the cold stays on. Out comes the screamin teenager. NEXT

 

[WES999]

Consider an electric water heater. I was spending about $80/mo with a tank-less
oil DHW. The electric is about $20/mo.
See my post here:https://www.hearth.com/econtent/index.php/forums/viewthread/39434/P0/

 

[sbleiweiss]

As suggested already, putting in an indirect fired hot water heater will save you the most money. The problem with your setup now is that the boiler needs to have a low limit set to be able to supply hot water on demand. The oil boiler is losing heat up the stack constantly as the draft of the chimney constantly pulls air through it. The boiler keeps cooling off, hits the low limit and re-fires to heat back up. None of that heat was ever used by you... Once you put in the indirect tank, you can eliminate the low limit and fire the oil boiler only when there is a call for heat by the DHW or the house needs more heat.

One thing you can do to reduce the boiler losses is to install an oil vent damper. This will reduce the heat loss from the boiler due to air flowing up the stack. See:
http://www.pexsupply.com/Field-Controls-OVD-6-6-Oil-Vent-Damper-11822000-p

I calculated that I was using almost 200 gallons of oil per year due to the fact that the boiler had a low limit set and my boiler was old and poorly insulated. That was almost 1/3 of my total oil usage. I had an indirect tank already, but I did not realize I could bypass the low limit.