This thread has been bookmarked. Visit your bookmarked threads to review.
Post a Reply to this Thread
Boiler is cycling but no demand for heat (13 Posts)
Boiler is cycling but no demand for heatI have a Burnham V-13 boiler and Beckett AFG burner that was recently serviced and had an 84% efficiency combustion test. Throughout the summer and now into the fall, we have not had the heat turned on. However, the unit kicks on several times throughout the day for about 40 seconds - 1 minute, then turns off. (and we are not using any hot water) It seems to happen more now after our annual service, but that also happens to coincide with the colder weather. Is this functioning as designed?
Burner cyclingIs this a steam or forced hot water boiler?
How do you get your domestic hot water? If the domestic hot water comes off the boiler, look to see if the temperature was turned up on the aquastat although I would expect it to run somewhat longer if that were the cause.
Are there any lit led's on the controls when this happens? that might lead us to the problem.
Try turning the thermostat up to get some heat and see if it performs normally.
Take some pics of the boiler and it's controls so we can see what your dealing with.
BobSmith G8-3 with EZ Gas @112,000 BTU, Single pipe steam
Vaporstat with a 12oz cut-out and 4oz cut-in
Beckett AFGIt could be recycling if it is trying to heat your water. Do as was suggested in the last post and turn your heat on and see if it does the same thing. If the burner loses flame signal it will automatically recycle and try again until it has reached a number or tries and locks out.
Are you having to reset your burner? You may need to check the cad cell and make sure that it is not dirty and can "see" the flame properly. These are also very easy to replace.
Also you may want to just make sure nothing is blocking the burner and that they cleaned your diffuser when the performed the maintenance. That way you know there is not soot build up blocking the flame from being seen by the fire eye. You may also want to check and see that all the wiring connections are tight.
Here is the address to a manual for the Beckett AF/AFG burners. Hope it helps!
http://www.beckettcorp.com/Protect2/techsuppt/product-manuals/6104BAFG.pdfThis post was edited by an admin on November 11, 2010 5:11 PM.
during the clean outthe mechanic likely turned the low limit on the aquastat up. ( to get the burner to fire) He may have forgotten to turn it back to the original setting. This only applys to a warm start setup. Check and see what aquastat is on this boiler (the grey box about 4'' by 8'' likely a honeywell control) Better yet take a pic of the aqaustat with the cover off. And as the other have said does this unit heat you DHW?
More infoThank you all for the quick replies. This is a hot water system with cast iron baseboards. We have an electric water tank, but it is connected to the boiler so I assume that does the primary heating of the water. I am attaching photos....I discovered that the hi-lo was 180/160. Should the low be turned down?This post was edited by an admin on November 11, 2010 10:34 PM.
Cycling:That is a really poor way to heat water. It may barely work. There is a better way.
Connect the water heater like it is a water heater. Full size (3/4" Copper) to the cold and hot. Put a bronze circulator on the bottom drain connection. A Taco 006BT is what I use. Pump it out of the bottom of the heater and to the inlet/cold side of the tankless. Pipe the outlet of the tankless to the cold water inlet of the water heater, at the top. You can pipe it in 1/2" tube if you wish. You do not need any wiring of the water heater other than to use the bottom single pole thermostat as a switch to turn on the circulator. When the tank is cold, the circulator will start. It will take the cold/cool water off the bottom of the tank. It will pump it through the tankless coil and the boiler will sense the drop in temperature, causing the burner to come on. It does it on temperature drop. There is no electrical connection. The hot water from the tankless enters the water heater through the cold and is sent to the bottom third of the tank by the dip tube.
I've done this for over 35 years. If you have a tankless, I always do this. You can set the high limit to 160 degrees and the house will take this for most of the year, maybe all the year depending if the boiler and system is over sized for the application. You can set the low limit/operating control at 140/145 degrees. When you get a heat call, the boiler will jump to the high limit setting. Most of the year, the boiler and the few gallons of water you have in the boiler will be at 140 degrees. If you have a tankless, I consider it a lot cheaper than a indirect because you don't need to get into the heating part of the heating system and wiring. I temporarily connect the pump with a cord whip and a extension cord until the electrician gets there. And you can control the tank temperature by the bottom thermostat. A 50 gallon is fine and a 80 is overkill. But the set up is a lot cheaper than a indirect and you still get a warm start boiler system.
Cold start $ucks.
A warm start cleaned every year (if it needs it) will use far less fuel because it stays clean than a nasty cold start and all the insulating $nots that show up in a year.
Works quite well for me.
Also, it is MY experience that THAT control is notoriously prone to failure and it may be not operating the differential properly. It that has the capillary tube into the tankless, I've always had problems like you describe. Sounds like the control is failing.
preheatingIf the domestic water is flowing thru the coil in the boiler 1st, it will come on as the temp drops. Also can't see pic with a shadow, but low limit should be about 110-120. Looks like 150?
control tempIf you set the low limit at 110/120 degrees, you will get condensation. Better to run it at 140.
CO warning and chimney damage waringThat heat saver on top of the boiler Is bad news. It can burn through and leak into the living space and also it can reduce your stack temperature to the point your flew gases condense in the chimney and wreck the flue tiles. Remove that and replace with proper round smoke pipe please!Cost is what you spend , value is what you get.
listen to charlie that heat re-claimerhas got to go, there outlawed in a lot of areas. They can also plugged easy if something goes wrong with the burner. As for the tankless coil they never work well, time to invest in a indirect tank. It will lower your fuel bills as you can keep the boiler low limit lower + have more hot water.
Tankless:"listen to charlie that heat re-claimer
As for the tankless coil they never work well, time to invest in a indirect tank. It will lower your fuel bills as you can keep the boiler low limit lower + have more hot water. "
A "tankless heater" is a "indirect coil" inside a boiler, heated by energy. A "Indirect heater" is a "indirect coil" inside a water heaterstorage tank. You must pipe the boiler water to the water heater so it can heat the water in the water heater tank. With all of the problems of leaking coil connections.
When you use the coil in the boiler, you pipe the water in the heater to the boiler tankless. You use smaller pipes. If you use a indirect, you must cut into the boiler water piping, add pumps and valves and do electrical wiring.
This is a oil installation. Unless someone is committed to switching to gas, I would consider this.
If you gave someone a price to get rid of their tankless to install a indirect water heater. Which may mean throwing away a perfectly good water heater, so you can sell an indirect. You give them a price. If they ask me for MY opinion on what to do (remember, customers don't tell you they already have a price and opinion), I will tell them that why disconnect a perfectly good tankless when I can install a electric water heater (and not use the electric), add a pump and some minor wiring, and they will save a lot of money because they won't need to run their boiler as hot. I give them a price to make the change. Maybe they weren't going to spend the money for your install. My price is considerably lower than yours. They go for mine because it costs less.
You must give people choices.
If you own a oil company and you want to keep customers, you must do what you must to save the account and save them money.
Most indirects do not perform up to their rated outputs because the boiler is far undersized for their application.
Whenever I see a straight tankless, I see an opportunity to sell a water heater. A 50 gallon electric water heater is the cheapest hot water tank you can buy. It is heavily insulated and prewired for what I want to do.
When I did a lot of electric heat conversions over to hydronics, they always had a electric water heater. It was a selling point to save the water heater and use it over.
Hey but, you guys with the indirects are right. They are the best. For gas.
For me and oil, storage tanks work far better.
And I won't even go to the area of cold start. DISASTER!!!
I cant seemto get more then 5 years out of those tankless coils. Out in the country where water can sometimes be hard these coils plugg in a hurry. I've seen guys use the electric heaters as storage..not a bad fix, but thats not for me. Its cheaper for the customer to go indirect rather then install a complete water softner system or burn throu coils year after year. Although both indirect and tankless are tough sells when the homeowner can go to homedept and spend a coulpe hundred dollars for a electric heater. As for the cold starts, you hit the nail on the head ice, bad news.....althou the little biasi can take it with its ultra low water cap.
Because I drain/winterize a lot of houses, I always pipe a system for easy draining of things. This includes isolation valves and drains on a tankless to the water heater. When done like that, it is an easy step to 32% muriatic acid and cleaning out the coil to "like new" status.
If folks have water so bad that they need water softners, they are ruining their plumbing systems if they don't have them. Let alone the increase in soap. And if they have low Ph H2o, they need to get the PH up to make the softner work properly.
But your comment about going to The Big Orange Rip Off, it proves my point that a electric water heater is the cheapest way to go. The coil can get pretty raunchy and still make hot water. The trick is that it has a lot of time to heat the water.
Also, HONST, HONEST. I've seen Indirects that didn't heat water anymore and were replaced. "I" took out the coil. The potable water side of the coil was completely encapsulayed by lime scale. Insulating the boiler water from the transfer coil and the potable water. The lime will percipitate out of the water onto a hot surface. Once the scale starts, it's a short step to boiling inside the scale.
For what it is worth.