Outdoor reset

Jim Pompetti

Last April, a law was passed ,that make it mandatory to have outdoor reset on all boilers. Does anyone know this as fact.

unclejohn

Sounds like

Something the idiots in congress might do, but i'm not aware of it.

Terry O

Actually...

The new standards for residential boilers were passed in 2007 taking effect Sept 1st 2012.



See link:

http://www.achrnews.com/articles/120154-new-residential-boiler-standards-effective-sept--1



The new regulations do not say ODR type controls must used, only that "Automatic Means for Adjusting Water Temperature". must be used. Some boiler manufacturers have chosen to use "thermal targeting" controls such as the Hydrolevel.



Any unit manufactured after the Sept 1st date must comply.

paul_79

outdoor rest

i just installed a knight wall hung 110 and while reading the instructions on page 53 it stated the united states energy policy and conservation act requires residential boilers with inputs of less than 300,000 btu/hr to be equipped with a control that automatically adjusts boiler water temp in relation to heat demand .

bob_46

Semantics

In the 1960's I installed a bunch of simple hydronic systems in small three bedroom ranch homes. The systems had cast boilers baseboard and ONE pump NO zone valves. The pump ran continuously 24-7 forever. The only controls were a 24V transformer, T87, limit and gas valve . No bypasses no protection against condensing. The temperature of the boiler would modulate with changes in the outdoor temperature all by it's self. No reset controls etc.. I have had this system in my own house since 1982 and there are no signs of rust or sooting. It seems to me that this setup meets the new regulations except for one thing. A wall thermostat responds to ACTUAL changes in the load and the regulations say that the means of control should respond to changes in the INFERRED heat load.

CMadatMe

Means For Adjusting

The inferred load. In other words. Pre Purge until the boiler sees 140 return or 2 minutes which ever comes first before the burner will fire. On a call for heat, the boiler pump will run, the boiler is looking for 140 or 2 minuted which ever comes first.



Just another way around ODR just like someone in the A/C world came up with as long as I don't ship R-22 units charged I'm ok.



The new talk is that DOE is looking to change the Energy Star Rating from 85% to 90% and mfgs of boilers are not too happy.

Ron Jr._3

Big caveat .

Boilers that maintain temp for a hot water coil are exempt .



We use them anyway . In case they step up to an indirect or storage tank . And most of these controls come with an added benefit , built in low water cutoff ....

SWEI

Semantics

"The temperature of the boiler would modulate with changes in the outdoor temperature all by it's self"



IS reset control.  How did it detect outdoor temperature?

bob_46

Reset

The colder it gets outside the more time the contacts in the stat stay closed because the load has increased. I know that sounds flip but thats how it works. At the time I designed my system I was going to Hydropulse school and got brain washed. I hoped to get a pulse

and sized the baseboard for 150º water.After I installed and serviced a couple dozen pulses I changed my mind and opted for a SlantFin Galaxy . The water temperature just follows the load and never hits the limit. Its the same way gravity systems work. Another

benefit of the constant circulation is there is never any residual heat in the boiler.

Gordan

Large thermal mass

This has been seen by some who have put bang-bang boilers with just an aquastat as a control on old gravity systems or other large thermal mass emitters. The water temp never gets a chance to climb to the setpoint before the thermostat cuts out the call for heat. It does seem like a thermostatic boiler bypass would be a good thing under those circumstances.

Ron Jr._3

Why have the circ run

even in the summer ? Back then a simple relay with dry contacts was pretty cheap . I'm sure electric was cheap too ............ How often did the circs have to be changed running 24/7 ?

bob_46

Pumps

Ron, most homeowners would flip the switch in the summer. The pumps were B&G 100's.

I didn't dream this control scenario up, this is what was recommended by IBR at that time.

We didn't replace pumps we rebuilt them. We carried impellers, seal kits, couplings, bearing assy. , wicking, motor mounts, motor centrifugal starting switches and motors on the truck. If you kept them oiled they lasted a long time.

Ron Jr._3

I get ya

I liked doing things by the KISS method too .



As an aside , we did a few gravity hot water changeouts . 2 or 3 we left gravity . I was kinda amazed how fast the rads heated up , even without a circ .....