is boiler outdoor reset control worthwhile for residential

Larry (from OSHA)

First of all, thanks to Dan for providing the site and all who contribute to this forum.
I live in Minnesota and have a 3000 sq. ft. home with fin tube baseboards built in '62. The boiler is a Weil McLain HE-5 Series 2 new in '84. The circulator is a Taco 007 and I'm running 3 zones with Honeywell zone valves. I am planning to replace my direct fired 40 gal. dhw heater with a Bradford White 65 gal. indirect unit. I've been looking at the Honeywell AQ475A aquatrol boiler reset controller as a way to get a little more efficiency and perhaps more comfort with the system. It appears that the price of natural gas is only going up. The local wet heat guys I've talked to say it isn't worth it for an on demand system like mine. If anyone cares to offer their perspective, I'd surely appreciate it.

john_24

outdoor reset

I have installed outdoor reset controls on quite a few residential applications and the customers are very happy with the result.I have used them on both constant circulation and on demand like you are describing with no problems to date. i prefer the tekmar controls with priority for the indirect so i am not familiar with the control you are planning on using.

john

J.C.A._3

I Agrree with John,

Why run the horses , when a trot will do ? Setting up the control properly, I see no reason NOT TO ! Why pump 180° water , when 135° will do? If the demand comes for hot water, it pumps up to the design temp, but that will just satisfy the Temp. sensors a bit quicker when the demand is gone. Chris

Bill NTSG

Just forget....

about money for a minute. Forget about pay-back.

Do it for you , you're worth it. No more temperature swings...68°-69-70-71 back to 68 and start all over etc. No more expansion and contraction noises as the radiation goes from 60° to 180°.

Reduced drafts, reduced infiltration, just constant warmth. Like replacing the heat as it leaves your home a little at a time. Cruise control. Instead of letting everything cool down and then dumping a bucketful of heat in to replace the warmth in a cool room you can just let it trickle in a little at a time as required.

You can't change the boiler as the temperature changes out doors. Like a summer shirt, sweatshirt, light jacket, winter vest, hat mittens etc. You can't change your radiation , so why not change the water temperature???

For every 3° you reduce the boiler temp. you can realize a 1% annual fuel saving. I am not real familiar w/the HW control but I am familiar with Argo, Tekmar, Buderus and Viessmann.

If you can set your curve low enough you can achieve near constant circulation with your system. Your room t-stats will act as a "high limit" to prevent overheating. I would find a new heating guy, some one versed in "new hydronics".

New windows and insulation in your '62 home would be a wise investment also.[if you have'nt done so already] I almost doubled the size of my 1911-1950's home and cut the heating bill almost in half.

Unknown

Outside reset works &,,

it will likely do everything you read about.

Suggest you get one you can adjust the heating curve on. Tekmar pioneered this technology so, I reccomend them highly for their control units.
Those who claim it isn't worth it are not seeing the BIG PICTURE. Savings, comfort & value. Just do it.

NOTE: Will not solve the problems of the world.

Gary Wallace AOL IM; Radiantfloors

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

hot_rod

Just be sure

you protect the boiler from extended return temperatures below the condensing limit. Generally in the 130- 140F range, depending on the boiler brand, construction and fuel type.

Some controls have the option to sense, and react to the return temperature, make sure you address this.

hot rod

hydronicsmike

Outdoor Reset

Like all the others said. Outdoor Reset is the way to go. Not does it only save and earn you money in the long run, it also ups your comfort level by a huge amount.

When ever it comes to energy usage, I always like to look at anything that can lower the consumption as an investment. Many, including myself, were pretty unlucky with some investments in the last couple of years because of the market change. Investing money into anything that allows you to cut down on the energy consumption is a definite investment that is guaranteed to earn you money one day. A Reset Control with DHW feature can pay for itself in many cases within the first 2-3 years. After that it is earning you money. Fuel will never be free and it is also NOT very likely that the prices will drop considerably anytime soon.

Funny, but when I ask students in my classes about their annual fuel bill, many don't know. I guess the wife usually pays the bills....;)

But I learned that a considerable average for a Residence usually runs at around 1000$/year. Am I off by much?
If an Outdoor Reset Control can save you between 15-25%, you can watch the change in your pocket adding up. I have been informed by customers that some have paid for their Control within the first 2-3 years. (Of course this is all subject to a lot of variables).

I hope this helps. Did you notice that none of the fine gentlemen here said "it isn't worth it"?

Mike

Larry (from OSHA)

thanks

for all the info. this boiler has an induced draft and the stack temp runs about 345f. about a foot from the boiler exit after running up to temp. (140-180). do i need to be concerned about flue gas condensation with this type of system? also, there seems to be no shortage of opinions about air eliminators. my boiler supposedly has some sort of air eliminator in the casting on the leg to the expansion tank (large in the rafters type-no bladder) as opposed to a spirovent on the supply. since i'll be adding a zone and associated piping, it's really no big deal to add an air eliminator at the same time. make sense or a waste of time and money?

Larry

Larry (from OSHA)

yes

i did notice all in agreement. is this an east coast thing or what? i've heard that the good ideas start on the coasts and work their way into the midwest.

thanks again to all for the perspectives.

larry

Bill NTSG

Larry

Unless you replace your steel expansion [plain, not bladder] you will only find grief if you add a spirovent or high vent and all of your automatic vents at radiators. You "want" to herd all of the system air into the expansion tank so that it does not become water logged. As stated above the automatic vents will leak eventually. A piece of dirt or rust will get under the valve seat and the water will go through the ceiling, or across the white carpet or ruin the hardwood floor. It just does.

A by-pass pipe between the supply and return will help avoid condensation issues. Coin vents, or manual air vents as others call them, at the radiators should be fine. In a perfect world your vent would be on the return side of the radiator opposite the supply inlet. But is not a real issue. I would not go to the trouble of moving things , you will find no benefit.

As far as the TRV's are concerned and as another poster mentioned, I would not be so much concerned about supply and return but about direction of flow. They DO NOT like to close when installed backwards. This by personal experience, you can not believe how much noise a little valve like that can make. Good luck with your project.

BillW@honeywell

AQ475

With our Aquatrols, you have a choice of how you do your reset. BTW, reset is nothing new, commercial building have been using pneumatic reset systems since the late 19th Century! The AQ475 accomplishes reset by varying the boiler water temeperature, basically, the colder it gets outside, the hotter the water delivered to your baseboards, radiators or coils becomes. Bill very aptly described it as cruise control for your home. It also provides for automatic warm weather shutdown.

Reset systems are proven energy savers, plus your comfort levels are greatly enhanced. Don't forget that your home is a system, each component of which effects all the others. The most efficient boiler with reset won't live up to it's potential if the insulation is poor, windows are leaky or the system isn't sized properly. Get a good hydronic heat contractor, get a heat loss done, and you'll never regret the major investment that a new heating system is.

Visit try http://hbctechlit.honeywell.com, you can download a spec sheet. Thanks for using our products!

Dick_2

steam system

can the outdoor reset be used on residential steam?

Unknown

Not on one pipe

On two pipe, in a very big building, you can reset the steam temperature. It is too expensive to do it on a small scale. Check out Mepco, they sell the stuff still.

http://www.mepcollc.com/VV.htm#mepco2

Noel

hot_rod

The boiler control

aquastat generally have a 15-20 degree delta t. So, if your boiler shuts down at 180F, it may fall to 160- 175 before the burner fires again. Not a problem.

If you install an boiler outdoor reset control, it takes control of the boiler operating temperature. As such running your supply down to 135- 150 may show return temperatures below what the boiler likes to see :0

In this case a mere bypass can help, some. It allows some blending at the boiler to keep the temperature up. Some larger systems will use a bypass pump to assure some temperature.

Keep in mind neither of these methods are able to monitor and know EXACTLY what temperature is returning to the boiler. As the load on the building changes with additional zones calling, the bypass cannot sense this and assure adequate return temperatures.

Still, I feel it is best to have a control or mixing device that is thermostatically operated to watch and respond to that return temperature at the boiler, especially if you are talking 135 supply temperatures on mild days. Well within the reach of what a reset control will provide on mild heating days. Most reset control literature gets into this, along with piping methods to eliminate the problem.

If you haven't already, check out the excellent literature on this subject, available at the www.tekmar.com website

hot rod

hydronicsmike

Noel...

...Do you think it is not worth while adjusting the amount of time that steam is established based on outdoor condition in a residential system?

Mike

Unknown

Oh, yes I do!

That's a little different than reseting the temperature based on outdoor air temp.

I like HeatTimer controls for that. We endorse this on big buildings and on modular or multiple boiler set-ups.

I haven't tried the tekmar control yet, Mike.

Noel

hydronicsmike

Fair enough.

Was just wondering. I am not a steam expert by any means and wanted to find out what you thought. Thanks.

Mike

hydronicsmike

link update

www.tekmarcontrols.com. - Control manufacturer

www.tekmar.com was already taken. - Teledyne Tekmar is the premier manufacturer of Gas Chromatography Introduction Systems and Automated Total Organic Carbon Analyzers (-> Headline of their web site)

Thanks Hot Rod.

Mike

Steve Ebels

Hey! Be careful who you're saying

Is behind the Right or Left Coast. (Grin) I'm from Michigan and I don't believe that we've put in more than 3 boilers in the last five years without a reset control. They just plain work. Especially on boilers that are able to take low (100-110*) or less return water temp.

Bill NTSG

Hot Rod

I should clarify my above post. I have a Vitola Bi-ferral , Viessmann, and it will take 95° return water all day long w/o condensing. To Larry, it is not a "conventional boiler" and not every boiler is designed to work in these conditions.

Hot Rod is correct prolonged low temp return temps can cause flue gas corrosion and possible thermal shock.