by pass low limit

Andre

The question was asked, how do I by pass the low limit on a L8124 relay? If you call the manufacturer they will never give advice on altering a control, but, pull the white wire on the top right and pull the red wire out of the low limit and wire nut them together and you now have a L8148 high limit only. Why was that so hard. Know one got that right.

In regards to warm starts vs cold starts. I have a Crown boiler TWZ125 with a L8124 relay set at low 130* and high 195* with a mega stor indirect water heater. when the boier comes on at 130* it takes two minutes to get to 140* before cut off, this by the way is with no call for heat. It takes eighteen minutes to cool down before re-fire. At this rate the boiler runs six minutes an hour to keep the water temperature at 130*. Times 24 hours a day = 144 minutes a day. Times 365 days a year = 52,560 minutes a year divided by 60 minutes an hour = 876 hours a year. With a nozzle burning 1 gal per minute, thats 876 gals a year to keep the water at 130*. With no. 2 fuel lets say an average of $1.80 per gal thats $1576.80 a year just to keep your boiler cleaner from cold starts. Im sure its not quite that simple but thats pretty darn close. I'm going with cold starts.

Mark Walnicki_2

your mpg may differ?

I keep my oil-fired boiler (with indirect) at ~130* year round. Out of curiosity, I applied your calcs. to my house, taking into account my average annual fuel cost and my average annual fuel usage.

Based on what's occurring at your house (2 min. on, 18 min. off), half of my annual cost for fuel oil is because I keep the boiler warm.

I highly doubt this is the case, but now you've got me curious. I wonder how much extra I really am spending to keep the boiler warm? And if it's really considerably less than what it would apparently cost you, I wonder if I have less stand-by losses for some reason? And although I don't mind quick, down & dirty calcs., (a bit of a fan of them, actually), I would respectfully submit to you that I think there are quite a few factors that have been left out that may influence the real numbers.

Either way, you've given me something to "chew on" when I'm traveling tomorrow! Thanks! :-)

Weezbo

interesting, observation.

Good luck.

Andre

keeping the boiler warm

I guess there are other factors involved in calculating those 2 minutes on, 18 minutes off, starts. You would have to deduct all the times the boiler would come on when there was a call for (lagitimate heat calls) during those 24 7 calculations. There would be more of course, during the heating season. Where I live in upstate New York thats about 7 months out of the year, diminishing for more heat calls as the months warm. That would be very hard to figure, But, lets cut that in have and you still have significant savings. Thats 438 gals of fuel a year or $788.40. Cold starts are still looking better.

Ron Schroeder_3

Hi Andre,

Good observations. Several things to concider also.

In the heating season, does the standby losses of the boiler help heat the house? In my house, it does.

What is the differential setting on your low limit? A wider differential will increase the burn time but will also increase the off time even more.


Personally, I am now running 130 degree warm start in the heating season but cold start with 140 degree low limit circulator control for the indirect in the non-heating season.

Ron

Ron Schroeder_3

Don't quote me on this but I think it is the B wire near the upper right (not the W wire) that I disconnect and tape off to disable the low limit without disabling the circ control.

Ron

lchmb

wow

I have a Slantfin boiler in my cellar. Low is set at 160 high 190 with the differential at 15. My boiler run's at most once every hour if not hour and a half. The boiler is mainly used for hot water which is by coil and my yearly usage is 300 gallon's. Two minute's on 18 off seem's a litte odd. I think I would be looking into thing's a little further....

Bill Nye_2

WoW!

So how come I can heat my house and have plenty of hot water ALL YEAR 'ROUND for less than 700 gallons of #2 fuel?????

B. Tice

Something is not right.I have many accounts with coils that are 160 low limit and they don't even use 800 gallons a year. I have very few that use more than 1200.

Unknown

We have thousands of accounts

where the boiler temp is kept 180 year round . Average oil consumption is 800 gal. a year , give or take . The homes are not big by today's standards - less than 1500 sq. ft. with standard extensions . On the other hand , they are not insulated well . This is on Long Island .

Unknown

Andre , the numbers are not even close

If your boiler is running 6 minutes of every hour just to stay at the minimum of 130 , there is something very wrong . My Peerless WBV3 maintains 180 all year long . It sits under my stairs , right next to the living room . When there's no call for heat or hot water it'll stay idle for hours and run maybe a minute to bring it back to 180 . It's very easy to keep track - I gotta adjust the TV volume when it comes on .

I burned about 900 gallons of oil through the last heating season . 1200 sq. ft. home , insulation nonexistant in 3 of 4 outside walls , and 5 people taking showers .

If your home is alot larger , of course you'll burn more oil . But that $1500 + number , just to maintain 130 in the boiler is unrealistic . Is your boiler located in a cold area ?

Weezbo

are you perhaps able to change the burner to more

realistic outputs for the space? could a lower firing rate be used that wont cause condensing temps in a stack and yet still maintain comfort in a space? here is an example,2800sq ft, cathedral ceilings SoG ,heated two car garage,4 bedroom,large glass,three bath....outside designe temps in the -60 F range....8 zones,5 radiant2 convector base board,water maker.........2 adults 3 young children,formal dinning room.......... .5 gallon an hour ...........partial reset 145 170 range variable speed injection.......i do not suggest that your building is quite the same standard of construction,however clearly there is a benifit to use the heat and distribute the heat properly,and as many have tried to say there appears to be something drastically off tilt with the current operation of Andre's boiler. lets ask What size nozzle might be in the boiler and when was it last tuned?

Andre

time for help

> realistic outputs for the space? could a lower

> firing rate be used that wont cause condensing

> temps in a stack and yet still maintain comfort

> in a space? here is an example,2800sq ft,

> cathedral ceilings SoG ,heated two car garage,4

> bedroom,large glass,three bath....outside designe

> temps in the -60 F range....8 zones,5 radiant2

> convector base board,water maker.........2 adults

> 3 young children,formal dinning room..........

> .5 gallon an hour ...........partial reset 145

> 170 range variable speed injection.......i do not

> suggest that your building is quite the same

> standard of construction,however clearly there is

> a benifit to use the heat and distribute the heat

> properly,and as many have tried to say there

> appears to be something drastically off tilt with

> the current operation of Andre's boiler. lets

> ask What size nozzle might be in the boiler and

> when was it last tuned?



Its a new Crown TWZ125 boiler with a 1 gal ph nozzle. With the factory settings. Me and a friend did a replacemnt install ourselves, in my home to save labor costs in the initial change over. With the intent to hire a qualified heating contractor to come in and check out the istallation and work out any bugs or mistakes. Yes, what is going on, why does my boiler come on so frequent? I know the math calculations where very basic and simple but, based on my observations is this correct in my case. I have some other problems as well, time to make that call I guess. Any input is very welcome thanks.

Andre

Bill Nye_2

Andre

Maybe, check the aquastat . What I mean is check the insertion depth of the capillary tube and bulb.

I like to take a piece of wire or a lonng phillips screw driver. Insert it all the way into the well and mark the reference by bending the wire or holding your finger on the screwdriver shank. Use this reference to pull the bulb out far enough from the aquastat case so that it will bottom out in the well.

The other maybe. Maybe you have a shorted t-stat wire or miswired wire that is causing the boiler to cycle off of high limit.

zeke

Since it appears that from your calcs the duty cycle for idling is 6min/hr then you are talking .1*140,000 Btu/hr for a 1GPH nozzle or 14000 BTU /hr or about 5KW.of continuous 24/7 wasted power. You have quite an insulation problem around your boiler if that is the case. Or is the heat going up the stack?

zeke

By the way, Andre , if your first observation of 6min/hr of wasted heating is correct, then your second statement that during the heating season you would deduct the effect of heating is incorrect, since the heat losses you are talking about are due to heat convection and radiation from the boiler to the boiler room and if anything during the heating season they would be higher.