I've just installed an Intellicon HW+ 3250 for use on my residential hydronic heating system and I believe I may be having problems with discrepancies between the aquastat boiler temperature readings and the HW+ thermistor on the boiler supply (output) line.

The boiler is natural gas fired National U.S. Radiator 101-6 (old, ~1955). The system is controlled with a Honeywell L8124E aquastat (currently no DHW even though it appears had been used in the past) with 2 zones. Initially I used the settings consistent with the HW+ defaults for a triple aquastat referenced in the HW+ documentation (rev. K) with my aquastat LO (B STAT) set to 150 and HLOLIM on HW+ at 145. The aquastat HI is set to 185. With these initial settings I quickly observed what appeared to be lockout (call-for-heat, burner off, circulator off) on an aquastat LO limit trip (150 - 10 = 140). On the initial call-for-heat the HW+ went into ECONOMIZER MODE (circulator running, no burner) with the sensor reporting 170. Soon thereafter, coinciding with the HW+ reporting a drop to 169, the circulator shutoff without the burner starting (HW+ still indicating ECONOMIZER MODE). The system sat in this state until I turner the aquastat LO limit to 120 (?!). From my understanding this indicates an aquastat to HW+ thermistor delta of ~30 degrees (170 - (150 - 10)). I then cleared the HW+ accumulated stats and let the system run overnight (LO / B STAT at 120, HLOLIM at 145). I checked the system after letting it run for ~24 hrs I still observed what I think are lockouts dealing with the aquastat LO limit. The HW+ reports an RT HRS of ~6.8 with an ET HRS of ~3.0. From what I've gathered (internet chatter, so take with a grain of salt) this is exceptionally low RT / ET ratio (also assuming the boiler isn't *extremely* oversized for my home). I believe the high ET reports are due to the circulator being locked out during ECONOMIZER MODE on LO limit aquastat trips (again LO / B STAT set to 120, HLOLIM at 145).

Some notes:

- When I observe a lockout it is always resolved by turning down the LO / B STAT (have had to go down lower than 110 in some cases).
- The HW+ sensor is insulated with a 4" wide strip of R4 fiberglass insulation wrapped around the boiler output line
- The boiler output line appears to be steel (or something of lower thermal conductivity than copper).
- The boiler output line exits the boiler from the top, the pipe diameter looks to be ~3" for 4 inches until the junction with the expansion tank supply line, the output line is then ~1.5" in diameter.
- I don't have the option of mounting the HW+ sensor on higher thermal conductive lines (copper) until after the zone valves ~4 feet from the boiler
- The boiler does not appear to be bouncing off the HI limit (i.e. aquastat sensor is not consistently reading lower than expected).
- The HW+ sensor reading appears to slowly climb 10-15 degrees after the burner shuts off after a call-for-heat.
- When the HW+ sensor stabilizes (no longer rising) after a call-for-heat, turning the HI limit dial and listening for aquastat clicks (burner lockout on/off) shows consistency between HW+ sensor reading and aquastat. Same on LO limit dial.
- I don't know how comfortable I am keeping the LO / B STAT setting so low considering the age of the boiler and the potential issue of thermal shock (?).

For now I've mimicked the system as a single aquastat system (aquastat HI at 185, aquastat LO at lowest possible setting and HLOLIM at 155) and haven't seen a lockout. The RT/ET ratio is about ~4 and I think this may be due to HW+ sensor lag on the output line (the HW+ thinks there is more residual heat than may truly be available...)

I guess my goal is to get the HW+ operation optimized on my boiler in a manner that won't damage the boiler. I am hoping someone might have some insight on how to address or further troubleshoot this issue

Thanks in advance

 

Hi,
interesting thread!
I installed the Beckett HM( poor cousin of your Intellicon HM) last January and initially had a similiar problem as yours ie. lockout, although mine was intermittant which I blamed on the inaccuracies of the aquastat and/or Heat manager sensors.
I fixed it by running my circulator whenever there is a call for heat, regardless of the boiler water temp. In other words I bypassed the Circulator cutout feature by running a "hot" to terminal ZC in my L 8124A aquastat ie. connect a wire between L1 and ZC.
Now my circulator runs whenever there is a heat call and I actually like it better that way because even 140 deg. water will give off heat in my radiators.
You may want to try that - it sure worked for me
BTW - I really like the Heat Manager. It virtually eliminated short cycling

 

Hey Tropedo,

Did you have your HeatManager sensor strapped onto a cast iron boiler output line?

I think my issue may be with the use of cast iron on the boiler output line. Cast iron looks to have 1/6th the thermal conductivity of copper (cast iron heats up and cools much slower than copper). The delay in the cooling of the pipe causing HW+ sensor to read higher than actual water temp. With this I can imagine the aquastat low limit trips and locks out the circulator but since the HW+ sensor is reading higher the HW+ locks out the burner thinking there is sufficient residual heat (and the LO/B STAT limit hasn't been hit yet).

With the aquastat LO limit turned all the way down I don't see any lockout.

 

Test tube,
my heatsensor is strapped right to the cast iron boiler output pipe and I insulated it with a piece of foam pipe insulation and wrapped the whole thing with metal tape. I also have a second sensor strapped to my DHW coil output pipe which is copper.
It's very difficult to get accurate temp readings and I've given up trying to do that.
For example my aquastat hi limit is set at 175 deg and the temp gauge on the boiler reads 200 deg when the hi limit shuts it down.
Which temp is right? - I don't know and IMHO it's not really all that important just as long as the system works as a whole

 

I had sent an email with slightly modified version of the original post to Initellidyne support.

I received a short response stating that I should check my CAD cell sensor. I didn't think they used CAD cell sensors on natural gas burners... I only have a thermocouple to lock out the gas valve in the absence of a pilot light.

I have my first A SAVINGS (average savings) report from the HW+, 44.7%. I am going to have to say "no" to that but would be happy if my gas bill proved me wrong.

Well see what intellidyne responds. There has to be different setup guidelines for triple aquastat systems with cast iron vs. copper output lines. I can't see the HW+ sensor keeping timely water temp readings from a strap on sensor mounted to a cast iron output line (as my experience with the LO limit burner lockouts might indicate).

Of course maybe my aquastat is bad.

 

Mr. Hammer might get p.o.ed at me again for saying so, but I find that result laughable at best.

In order to track savings, you would need to have pre-install historic data on past CCF useage data, correlate that to degree day data from the same period, collect data from the after install, and compare.

It's also pretty laughable that the 'tech support' said to check your CAD cell ...

IMHO the only thing that the HM or HW is good for is to increase the differential and solve some short cycling problems. It MAY save a couple/few percent in the process.

Why not call Mr. Hammer directly? I believe he indicated that he would be glad to discuss his product with anyone who did so.

 

I don't think anyone would argue it's a valid result. I only posted it to reinforce that I had a issue with circulator stopping on the aquastat low limit set-point during economizer mode.

I actually have this information courtesy of the local gas company going back 3 years (therms/mo, degree days/mo, and therms/degree day). We'll see how the HW+ does.

Yeah, an unfortunate misstep. Obviously the tech didn't read the whole email... We've exchanged a few more and we're on the same page now. I didn't realize the HLOLIM setting referenced in the docs was the lowest recommended setting and that it should be increased if one observes issues (i.e. original post). For some reason the language in the docs confused me.

With what I am paying for heat 10% savings is a return-on-investment of 1 yr. Even at 3%, the return is 3 yrs... I won't complain. I see a little more value in the HW+ than you do and that's ok.

Now you're just being vindictive... I've been lurking here long enough to understand you have a strong distaste for the HW+ / HeatManager. I do appreciate your skepticism and your help to others (regarding different topics) but it seems like you are tying to use my post to pick a fight...

 

No, not really... I'm actually perfectly serious! Brutally honest might be a better description. He indicated in his email that he would be happy to discuss... I hold no bad feelings for Jack. And contrary to your perception, I wouldn't call it a 'strong distaste' ... it's just that I don't believe the claim of 10% is all... I actually do think it's a good product. Easy to install, etc. And what Jack said about the ODR controls... well, sad but true is the fact that 99.99% of people wouldn't even have any idea wth they were looking at, let alone be able to grok what they are designed to do, or be able to understand how to set it up and adjust the parameters. In that regard, the HM/HW is the 'control for the masses' ... because honestly, they would convince themselves that it saves them 10% even if it doesn't ... how can an LCD display lie? I know a few ppl who actually have convinced themselves that the magnets they put on their fuel lines on their automotive conveyances actually increased their mileage.

Maybe you noticed that I recently even RECOMMENDED the product to someone with a short cycling problem?

I would be very interested to see the data you collect when yer all finished testing... and, I'll believe you if you tell me it saved you 3% in fuel. That's what I figure is about right. This is based on what MY HM would do if I let it... (I've got to disable other add-on controls of my own design to 'let it', and they save me about the same as the HM would).

 

I'm on my second heating season with the Beckett HM and I'm no HVAC pro by any stretch of the imagination, just an average DIY'er with a good knowledge of a little bit of everything.
Common sense tells me that there was a huge improvement in the performance of my heating system since installing this gadget. The furnace definately runs for much longer periods of time and less often now than it did before and that's a good thing by anybody's standard. My oil consumption has decreased but I am not tracking it to the penny. Even if there were no fuel savings, the decrease of wear and tear on my burner/furnace alone is worth it to me.
All I know is that the HM increases efficiency and greatly decreases short cycling.
I have no doubt that a proper ODR system c/w outdoor sensor would be even more efficient but for the ease of installation the HM is hard to beat.
As you said so profoundly, it is a gadget for the masses of which I consider myself to be a part of

 

Yep, and that short cycling issue is exactly where the HM/HW will shine. By increasing the differential, you can eliminate the short cycles. By curing a short cycling problem you most certainly could pick up a couple/few percent in fuel savings.

I might have been a little harsh on the 'masses' in my last post. Let me amend that to say that maybe 95% wouldn't know what they were looking at... not because they CAN'T understand, but because there are more important things in their lives than their boilers! And that's just fine...

Glad it's workin' out for ya Torpedo!

 

Well I have some preliminary results....

The Intellicon HW+ was installed ~1/02/2009. My gas meter read dates are around the 16th of each month (but occur later if the 16th occurs on or around a weekend or holiday).


12/2008, 32 days, 304 therms, 1246 degree days, 0.244 therms/degree day
01/2009, 32 days, 390 therms, 1640 degree days, 0.238 therms/degree day
02/2009, 31 days, 318 therms, 1475 degree days, 0.216 therms/degree day

So, 01/2008 was ~0.5 months with Intellicon HW+ and there was a small reduction in therms/degree day. It was also the coldest month we've had in about least 10 years and from what I can gather weather at the extreme of the boiler capacity is where the Intellicon HW+ savings would be minimal. Looking at 12/2008 and 02/2009 there's an ~11.4% decrease in therm/degree day.

This is absolutely not an apples-to-apples test. In late 12/2008 I found my boiler stuggling to heat the house (heat loss exceeding boiler capabilities) with aquastat HI limit at 180F and prolonged outside temps at or below 0F. After all my reading (thank you forum contributors) and spot checking with an IR thermometer I discovered my basement was a sieve (understatement). I did some quick sealing around the basement windows and doors, blew out the baseboards (nasty stuff in there) and sealed the living quarter window sashes with rope caulk (done at same time as Intellicon HW+ install). With these changes I was I was able to heat the house with aquastat HI limit of 180F down to prolonged outside temps of -15F. The sealing work seems to have had significant impact and I would even believe the cut in usage of 11.4% could be solely due to the work on the home envelope based on the observations above.

Does the Intellicon HW+ work? Eh, i might be more inclined to believe it if the "A SAVINGS" (average savings) readout wasn't reporting >35% compared to the ~11.4% my gas bill is reporting...

What does this whole experience tell me? I have a lot of work do with the home envelope before I spend any money on a new boiler or gadgets to support it... This summer I will be sealing and reinsulating the basement and attic...

Again, definitely not an apples-to-apples test and, I believe, not under situations where the Intellicon HW+ should perform its best (man, it's been a cold winter).

The only conclusion regarding the Intellicon HW+ at this time is that, for my setup, the "A SAVINGS" readout is extremely misleading...

 

Thanks for the well written report Testtube!

I believe I mentioned earlier that I insulated my crawlspace before the 07-08 winter, and I believe I realized appx 10% savings from that alone... and the infiltration you mentioned is a HUGE heat waster, perhaps even more than a lack of proper insulation.

Not sure though about the HM/HW not being as effective when the boiler load is heavy though. I think it depends more on exactly how oversized the boiler is relative to heat loss.

If the boiler is grossly oversized, it will hit it's 'magic number' of 170° regularly, and go into the 'economizing' mode. This is the 'SAVINGS' number that is being reported... and you know that I do agree it's misleading.

There was only about one week in January when the weather was cold enough that my boiler fired to high limit and the 'red light' on my bare bones Beckett HeatMangler ever went out... and that may have only been for one night when the temp dipped to 4.3° here. I only actually witnessed two boiler cycles during that period that the 'economizing' green LED lit up... there may have been more that night, but I was sleeping through it...

 

I want to add something else... actually in FAVOR of the device.

Your 35% A SAVINGS actually DOES mean that your boiler fired many fewer times during that period. So you HAVE probably saved significantly on the 'wear and tear' aspect...

But the bottom line is still that it takes X amount of BTUs to heat your home... and the single biggest and most cost effective improvement is always going to be in the building envelope. It's not how and when the BTUs are being made and distributed into the home, it's how well they are HELD in the home...

 

Well... minimizing the wear and tear will help. I need to squeeze as much life out of my current boiler as I can. I would like to seal up and insulate the house as best I can before I replace it. Considering how poorly sealed the house is currently I would imagine I would end up with an over sized boiler if I replaced *then* sealed. My goal is to do such a good job sealing that I am forced to install a boiler with an external air supply, i can dream... I already installed the CO detectors just in case!

According to the gas company for my square footage I am in the worst 5% of all homes and 20% of homes of similar vintage (pre-1920) for their service area. I think I have room for improvement.

 

Get it so tight that you need to install an air to air heat exchanger to keep it 'fresh' indoors... that's hard to do though...

I read lots of good things about the 'spray in place' foam insulation... it's expensive but worth exploring. Two birds with one stone, infiltration AND insulation, in one step! I'm thinking of having my crawlspace sill and rim joist done with it... keeps out vermin too! they will NOT chew through it... don't know why, but they don't... they'll eat steel wool, but not that stuff!... kinda uncomfortable with the fact that termite and carpenter ant damage won't be readily visible though... could be a 'show stopper' for me...

not to drift the subject... but...

 

testtube, nice report... one thing to keep in mind is that after about mid-January the solar factor starts picking up.

 

Who, good call.

I will add numbers from prior years... (d = days, th = therms, dd = degree days). The month listed is the meter read month.

12/2008, 32 d, 304 th, 1246 dd, 0.244 th/dd
01/2009, 32 d, 390 th, 1640 dd, 0.238 th/dd
02/2009, 31 d, 318 th, 1475 dd, 0.216 th/dd

12/2007, 29 d, 252 th, 1150 dd, 0.219 th/dd
01/2008, 33 d, 298 th, 1332 dd, 0.224 th/dd
02/2008, 30 d, 345 th, 1532 dd, 0.225 th/dd
03/2008, 31 d, 296 th, 1376 dd, 0.215 th/dd

12/2006, 30 d, 209 th, 0946 dd, 0.221 th/dd
01/2007, 32 d, 217 th, 1016 dd, 0.214 th/dd
02/2007, 30 d, 359 th, 1627 dd, 0.221 th/dd
03/2007, 28 d, 215 th, 1052 dd, 0.204 th/dd

12/2005, 30 d, 290 th, 1231 dd, 0.236 th/dd
01/2006, 33 d, 278 th, 1204 dd, 0.231 th/dd
02/2006, 29 d, 235 th, 1049 dd, 0.224 th/dd
03/2006, 29 d, 239 th, 1144 dd, 0.209 th/dd


First off, prior to this winter the thermostats were typically set to 60-62F. This winter we have an infant so I we've bumped it up to 64F. Now, there definitely is a solar factor winter-round. The first floor thermostat is in a room on the NE corner of the home which is well shaded. We spend almost all of our time in the rooms on the W side of the house with excellent sun exposure. This year with the thermostat at 64F the W side rooms are constantly 4+ deg warmer during the day. We can feel the temp drop with sunset (the wife-mometer has an alarm).

Looking at the above numbers it seems that there's a nice drop off in th/dd going from the Feb to Mar readings. I would take this to mean that in my home the solar-factor doesn't offer usage reduction until sometime after 02/16 of each year. This makes me feel a little better since it reinforces that the spot sealing, HW+ or both decreased my gas usage independent of a significant solar factor.

To go way off topic...

I really wish I could get the numbers from before 12/2005. In 12/2005 we had the house resided. One might actually be able to see this with the spike in th/dd for that month as the house sat for a bit of time w/o siding. With the residing they added ~1" rigid insulation and wrapped the house with a tyvek like material. We also saw that at some time in the past cellulose was blown in to augment the original hemp-in-construction-paper insulation. For some reason they removed and did not reinstall the basement storm windows (will rectify soon). From memory (don't have the hard numbers) our gas usage has actually gone up 10% after the siding install. So it would appear the chimney effect has been in full force the past 4 years increasing our gas usage, dang. I really didn't understand the effect of infiltration until just recently.

 

I just purchased a Intellicon HW+. Yhe type of heating systen I have is a gas fired hot water boiler model 204nc-TEI1 made by burnham. The red and yellow wires comming from the Intellicon unit, I am not sure if the yellow wire goes to the honeywell control unit (model R8285D) and if the red wire goes to the gas valve or visa versa.
Thank you all in advance for any sugestions
Frank

 

Frank, are you OK with all the other wiring? The instructions don't give you any hint as to the connections for the 8285... you do have options...

Do you have the wiring diagram for your boiler?

You have the electronic ignition, correct?

I need to think about this some... I'm not 100% certain you can integrate that control easily with your boiler...

In general, the YELLOW would go to the control, and the RED to the valve, but I THINK (as in I'm not sure! so don't take my advice yet) that it's the MV wire from the ignitor to the gas valve where you need to connect the HW...

 

I've spent some time going over the install on this...

You have options for powering the device. I would say it might be best to power it from 120 VAC on the WHITE (Neutral) and BLACK (Hot) wires.

In this case, the BLUE would be taped.

The BROWN would be taped.

The VIOLET would be taped.

All individually of course so they can't short together.

Should be GRAY, RED, and YELLOW left.

The GRAY is going to get wired to the terminal on the 8285 marked " C " which is the 24 VAC Common.

Now a little explaining why I think this should get wired this way, and if my thinking is wrong, somebody please say so, and also please explain why.

In the previous post, I thought that perhaps the device should be wired into the MV wire which comes from the ignition control and goes to the Main Valve on the gas valve... I'm taking that back.

Your system has a VENT DAMPER, correct?

I believe you want that damper to close, and the pilot to go out when the HW is 'economizing'... therefore:

On the 8285 is a terminal marked " Y " and I believe that there is an ORANGE wire coming from that terminal, going to the boiler LIMIT SWITCH.

Remove the ORANGE wire from that terminal, and wire nut it to the RED wire from the device.

Connect the YELLOW wire from the device to the " Y " terminal on the 8285.

When the HW is 'economizing', the burner, pilot, and vent damper will all shut down. The circulator will continue to run, as it should.

I think this is right... but again, if anyone sees a problem with it, please say so! Heck, even if you don't see a problem, say that too...