FuelSmart Hydrostat 3250Plus - set up


Old 01-30-18, 09:36 AM
Thread Starter
Join Date: Aug 2010
Location: Dutchess County, NY
Posts: 131
FuelSmart Hydrostat 3250Plus - set up

I'll apologize up front, as this may seem like a rambling rant, but I do indeed wish for, and respect, the advice of the experts here. First some background:

This is the system at my father's house...not my own. Pop goes to Florida every January, and I come over to check the house every 3-4 days. Typical oil boiler (Peerless WBV-03-WPCL) with FuelSmart Hydrostat 3250Plus aquastat (manual: Hydrolevel ) 2 zones (standard copper tube slant fin baseboards) and 40 gal. IDHW (i.e. no tankless coil). ***Boiler was installed early 2017*** He does have a maintenance agreement, as well as automatic delivery from the installer.

Chronology of events:

Late December: Pop mentioned that this new boiler had a lot of trouble keeping the house warm, especially on really cold nights (upstate NY), and seemed to 'run alot'.

**Disclaimer: I am NOT a pro. However, since I've had several issues with my own system, and have received lots and lots of gracious assistance from you experts on this forum...I'm pretty comfortable with how this whole thing works. I told him I could come over, and at least see where the current settings were (had a suspicion his HL was set too low).

Here's what I found: scrolling with the setting button on top only shows 3 settings:

HL - 170
LL - 153 (??)
ECO (Economy feature) - OFF

My initial thoughts:

1. HL - 170 is way too low to keep this 1860's drafty house warm when it's 0 to -10 outside (which it was for 5 days).
2. Why is the LL not 'off'? As I mentioned, he has an IDHW...no tankless coil. No doubt he wasted gagillions of gallons of oil over the summer...ugh.

Since I'm not a pro, and he does have a service contract... I was a little leery about opening up the a'stat. But I read the 3250Plus manual (seems pretty straight forward), so I figured what the heck?

Inside, I found that the 2 zones and IDHW were all wired together to T-T. Now, the 3250Plus has some gee-whiz features (Thermal-Targeting, IDHW priority) that are obviously not being taken advantage of.

I told Pop that - in my unqualified opinion - his aquastat was wired / programmed wrong, and if it were my system, I would:

1. Move the IDHW to ZC-ZR, so it would be priority.
2. Raise HL to 180-185 and see if that keeps house temp up to thermostat setting (68)
3. Set LL to OFF
4. Set HL diff to 20 or 30.
5. Try using the ECONOMY settings and see if the 'Thermal-Targeting" feature does any good (may just be a gimmick). Basically, I want to set it up as shown in diagram 3 on page 4 of the manual.

Since he was about to jet off to Florida, we agreed to just raise the HL to 180, and leave everything else alone till he gets back. I checked the house every few days this month, and all appears well.

Sunday Jan 28 4:00pm - came to check the house. Found an oil delivery tag on door knob...took 248.6 gals on Jan 26 (Friday)...uh oh.... Stepped inside - FREEEEEEZING! Checked burner: 'HARD LOCKOUT' My presumption is tank ran dry just BEFORE oil was delivered. I considered re-priming the burner myself, but since he has a service contract, I called for a tech.

9:00pm tech arrives, and I explain what I think happened...he agrees. I also vented a little, that Pop has automatic delivery (i.e. should NOT have been allowed to run out), and my feeling is that he burned more oil than needed with the LL set to 153 instead of OFF. I also told him I was puzzled about the way his installers had set up the a'stat. Here's a summary of our conversation:

Me: "It probably ran out because it was cycling more than necessary with the LL not turned off."
Tech: "Oh no, that's not why. Evvverybody's running out."
Me (in my head): "So your company doesn't know how to compute heating days and customer usage." LOL....

Me: "Speaking of LL, my father has an IDHW, not a tankless coil. Why isn't the LL set to OFF?"
Tech: "Ohhhh, there's lots of reasons for that. Sometimes older folks, like your father, don't want the boiler to cool off, because it takes too long for it to warm back up."
Me: "Ummm...that makes no sense."
Tech: "And also, keeping the boiler temp up reduces the moisture in the basement. I often tell people to run their boiler until they don't see steam coming from the chimney, then shut it off."
Me (giving him a puzzled look): "Ummm...Ummm...Huh? This is a cold-start boiler. I can't think of a good reason to NOT set the LL to OFF." Tech was now realizing that I wasn't an idiot. I also pointed to the big orange sticker on the front that says: "Low Limit: Factory set to OFF - adjust only if boiler has a tankless coil."
Tech (mumbling under his breath): "Whatever, if you want it off, I'll set it off."
Me: "Yes...thanks."

So my first question to you folks: Is there any legitimate reason to have a LL on a cold-start boiler?

We then had a brief discussion about filters:

Me: "I think you probably should change the tank filter and burner screen, since it was probably sucking sludge off the bottom of the tank."
Tech: "Oh no, that's not how it works." I couldn't follow his exact words, but something about the oil isn't pulled off the bottom...????

My second question: Should I have insisted he change the filters?

Again, I apologize for the rambling. Couldn't think of a way to cover all this without giving the details.

As always...thanks for all your help. You guys are AWESOME.

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Old 01-30-18, 12:03 PM
Join Date: Oct 2013
Location: United States
Posts: 2,688
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There is absolutely no reason to use the LL on a cold start boiler. It is incorporated into the control in case you have a coil. Those aquastats are made for multiple situations.

As far as your oil not coming from the bottom of the tank, are you feeding from the top in which case that is where the filter would be and since the supply pipe is usually a few inches off the bottom there wouldn't be chance of sledge.

If you are drawing from the bottom and you ran out, although not always necessary it is good practice to change the filter and check the pump screen, depending how old your tank is and how often you let it run down.

The crap is at the bottom of the tank and will get sucked into the line if the oil is allowed to run out.

Just my thoughts, hope this helps a little.
Old 01-30-18, 03:47 PM
Join Date: Jan 2017
Location: USA
Posts: 487
Just a comment and a question. The question; how large is the oil storage tank and could you make it bigger? The comment;; In my last house I had an oil furnace and a 1000 gallon in ground oil tank that I filled up in August of each year when oil in my area was much cheaper than it was during the winter.
Old 01-31-18, 04:35 AM
Thread Starter
Join Date: Aug 2010
Location: Dutchess County, NY
Posts: 131
Spott and Steamboy - thanx! for chiming in!

With the LL set to OFF, hopefully Pop will burn much less oil this year. And no matter what the Tech says, I still believe that contributed to him running out.

It's a standard 275 gal tank (vertical), with the line coming off the bottom. I decided not to push the filter issue, rather I'll have him call for a full service in the near future.

At that time, I will have the Tech re-wire the IDHW to the ZC-ZR terminals, and program the aquastat correctly to take advantage of the gee-whiz features. I'm fairly confident I could do it myself, but since he has a contract, I'll have them do it.

Thanx again! Wally
Old 06-12-19, 07:28 AM
Join Date: Jun 2019
Posts: 1
Similiar Issue

I have recently installed a Weil-Mclain boiler and the installer set the Hydrostat in a way that sounds like yours. It is summer time now and I want to reduce the amount of oil I use since I get my hot water off a separate system. With that said, the installers settings were HL 180, LL 160 and Economy OFF. From what I gathered from the manual, the value of the Economy setting uses the maximum amount of fuel. He works for the oil company so that might have something to do with it. I changed the values to the following: HL 180, LL OFF, Economy HI. When winter comes back, I will change the Economy value to 2 which is the number of zones I have. Do these settings make sense? Could i just turn the power off on the boiler altogether for the summer?
In the text above, it is mentioned that you are rewiring the ZC/ZR terminals. My understanding is that you do that only if you have multiple circulators.
Old 06-12-19, 11:11 AM
Join Date: Oct 2013
Location: United States
Posts: 2,688
Likes Received: 8
Part 1. With your LL turned off your boiler will only run on a call for heat so if your stat is turned down in the off months it will not run anyway so you can shut it off or not.

Part 2. ZC/ZR terminals are used when you have multiple zones which an indirect hot water heater is considered. It is treated and wired as another zone. If you do not use those terminals when there is a call for heat the pump will come on but the boiler will not start to reheat the water. Those terminals will activate the relay to turn on the burner also.

ZC = Zone Control. ZR = Zone Relay

Hope this helps a little.

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