Oil burner with Enertrol HWDT-R-S Settings

[bush8989]

I have a Smith BB14-*-3 Oil Boiler, Triangle Phase III Indirect Fired water heater, and an Enertrol HWDT-R-S.

I just moved into the house and I'm trying to "get to know" my system and make sure it is set to be as efficient as possible. The burner itself was tuned up 3 months ago but they didn't touch anything else. I'm curious about the Enertrol settings. The temp dial on it is currently set to 180 here in the CT wintertime. Should that be my year round setting or should I turn it down in the summer. If so turn it down to what. The round "time dial"??? What does that do and what should I set it to? The current time? The time I need the most heat, or hot water, or what? There is also a switch "std/mod". It is currently on std. Is that correct? What does that switch do?

When I do decide to upgrade the system should I go to a separate electric only H2O heater, these oil bills are killing me!

A picture of the Enertrol is attached

[Tom Sawyer]

Oh boy an Enertrol, blast from the past. If its working correctly the temp should be cranked back to about 140 and the timer, it is for domestic hot water if you had a tankless coil which you don't, should be bypassed. Taco, techmar, Beckett and others make digital models now that are much better. If you really want to cut your oil bill though, it's time to take the beast out of the basement. Take a look at system 2000 or buderus boilers.

[bush8989]

OK great. I'm pretty sure the timer is bypassed because it doesn't move at all no matter what time I set it for. I do have a Taco SR 502-2 connected to the boiler over by the water heater tank. Should the switch on the Enertrol be in MOD or STD, or is that bypassed too.

[Tom Sawyer]

Mod, is your 502 the xt model?

[bush8989]

No I don't believe it is. It doesn't say XT anywhere. It just says SR 502 2 zone switching relay 9300-525

[Tom Sawyer]

Too has. The xt is set up for tacos pc700 boiler reset control. Plug and play

[Dana]

Almost all older oil boilers in CT are more than 3x oversized for the actual design temp, which has a significant impact (and not a good one) on system efficiency. Outdoor reset (ODR) controls can give you steadier room temps and higher comfort, but if you're not getting 10 minutes/burn out of it it won't meet the nameplate AFUE, and at lower output temps it's rare to find a system with an oversized oil boiler with sufficient that doesn't short-cycle under ODR control at the low end of the temp range, but measure it. If the min-burn is 5+ minutes you're probably OK.

Beckett Heat Manager or Intellicon 3250HW+ economizer controls exercise the thermal mass of the system to best meet the heat load with maximum burn times (as best can) but also purge heat from the boiler into the system at both the beginning and end of calls for heat, to minimize standby loss. Parking the boiler at 145F a the end of a burn results in significantly lower standby loss than parking it at 155F or 180F, and purging heat until the boiler hits 140F helps too. It will usually beat ODR on efficiency when the boiler is 3x oversized, but not at 1.5x oversizing.

Before replacing the boiler itself it's important to determine the real heat load at the 99% outside design temp (which is about 6-8F in Ridgefield.) But at $4 oil it's cost effective to reduce the heat load on the house with air sealing and insulation upgrades, maybe even low-E storm windows, all of which improves comfort too. Back in the day when all windows were single-paned and insulation (if any) was skimpy, systems & boilers were usually sized on some idiot-proof rule of thumb like "35BTU a square foot times 2500 feet gives ya about 88K, so divide by 600BTU/foot comes to 150' of baseboard, and yer done." But they'd often installed a boiler with 100K of output and 165' of baseboard "just to be sure", for house with a true heat load under 50K, often under 40K.

With storm windows, reasonable air tightness and some insulation in the walls and attic the real heat loads are typically less than half that. Most people didn't know/care much about maximizing the comfort possibilities and replacement boilers were typically the same size, or even bigger "just to be sure", or sized to the radiation, not the heat load. Newer-better oil boilers have Intellicon-type heat purge controls AND ODR built-in, and can tolerate much lower return water temperatures than your existing beastie-boiler can- you don't need to hold the line at 140F return water. Oversized radiation systems can often deliver the 99%-ile heatload with 140F OUTPUT temp, which renders ODR somewhat useless if the boiler can't tolerate that for a return water temp!

In all instances it's better to go with the smallest boiler that meets the heat load, and in CT that is usually the very smallest boiler in a vendor's lineup. But do some sort or real heat load calc, Manual-J or similar, or an I=B=R quick & dirty spreadsheet, or fuel use against heating degree-day data to estimate. If your oil vendor stamps a "K-factor" on the billing (most do, in New England), that number is "heating degree days per gallon", from which it's possible to calculate a firm upper bound of the heat load of the house as-is/as-used. Do NOT size the boiler to the radiation, and do NOT use some "xxBTU/foot" calc on floor area- heat load is a function of exterior surface area & U-factors of the house, which can't be determined from floor area.

Whatever method you use for the calculation, and whatever number it comes up with, if you improve the insulation & air sealing picture, it can usually cost-effectively be made more than 10% lower, at $4/gallon oil (at any boiler effiency.) If the foundation walls are uninsulated, that could easily account for 15-20% of the total fuel use, even if you don't actively heat the basement, but there are other common heat leaks too- almost every house has some cheaper-easier heat leaks to fix.

Newer-better boilers are also expensive- hard to get out for much under $10KUSD for a well considered boiler with the requisite updates/tweaks to the system to get the most out of it. If you don't already have central air, ductless mini-split air source heat pump heating one more more large zone cost half as much to heat with than even a new-school oil boiler. For about $5K installed, a higher-efficiency name brand 2-ton mini-split has the capacity to heat than half a typical CT house, and can air condition it at VERY high efficiency, and is often a better overall investment than a higher efficiency oil boiler. At $4/gallon heating with oil is pushing the affordability & sanity limit, but it's a price point where even at 18cents/kwh electricity pricing, a decent sized ductless would pay for itself in under 5 years on the displaced oil use (let alone the fact that it can be 2x as efficient as a window-shaker type air conditioner, at much higher comfort, with much lower noise.) A few savvy heating oil dealers in my area have started installing & servicing mini-splits for their customers, having seen the handwriting on the wall.