Losing Hot Water

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  #1  
Old 01-24-12, 09:30 PM
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Losing Hot Water

I have a well mclain boiler with a domestic coil. I keep intermintently losing hot water. I will fire up the shower and then i get about 2 minutes of hot water and then cold. I go down to the basement when this happens and the temp on the boiler is 120 or lower, the boiler is firing trying to climb....sloooowly.

This happened after a "cleaning of the boiler" by a tech. Has never happened until after this. I called the oil comp and they came out and changed out the astat as it sounding like it wasnt calling for heat when it reached the low setting. Again still having the problem.

I went down their today when it happened again and noticed that one pipe to one of my zones was incredibly hot almost as if it wasnt closing when the domestic kicked on (the circulator didnt sound like it was running). Could this be the problem? Its a taco zone valve and every time i feel the pipe it feels hot over this zone as if it isnt closing. The radiators feel warm but not hot upstairs but the valve is still allowing water by. The other zone pipe feels normal, this one is def hot.

I had a problem awhile back with this zone not turning off. I replaced the thermo and it seemed to have solved the problem....until I just felt the pipe over that zone valve.

If this zone valve is bad could it be causing the hot water problem as the coil isnt getting 100% of the burn?

Thanks for the input.
 
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Old 01-25-12, 05:16 AM
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Yes the zone valve staying open can cause the issues you describe. But I dont think too much if the circ is not running.

The aquastat settings determine this.

What are the settings of the aquastat and the model #?

HI/LO/Diff ?????

What does the pressure and temp read at the boiler gauge?


What is the sepecific model boiler?

And take pics and post. We love pics.

Mike NJ
 
  #3  
Old 01-25-12, 06:26 AM
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I will post the requested info later when I am home, but I did think of one more thing. The new thermo I installed has a swing setting of 1. It is set at 68 so as soon as it hits 67 on it goes.. then it reaches 68 off it goes. I can hear this thing turning on and off all the time, the boiler fires ever time it turns on but then shuts off. One time when I was checking things out on the boiler i could hear something switch on and then off the boiler litterally fired for about 3 seconds.

Could this constant on and off of the boiler due to the thermo setting be giving me this intermittent hot water prorblem? I was thinking that the constant on and off of the circulator might be bringing the temp down slowly then when I turn on the hot water its not catching up?

I did check the zone valve last night and was getting the 24 volts when the zone called for heat and zero so I know the thermo works.

Thanks
 
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Old 01-25-12, 09:50 AM
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In addition to my last post I noticed that when the burner is firing for hot water the temp is slowly going down on the guage. This has never happened before..could the tech have not adjusted the burn correctly and therefore not heating the coild correctly?

Also when they replaced the astat they said the guage on the burner is not the same as what the astat temp reads. Does that make any sense?.. I was a little confused on that.

The astat is a honeywell l72240 1002. The temp on the digital readout says 195....my boiler guage says 170?

The burner is a well mclain gold pwtgo3 and it is powervented with a becket burner.

It has two zones and the tstats I am using are lux.

Thanks again for the help.
 
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Old 01-25-12, 09:58 AM
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You need to go into the settings and tell us what the hi/lo/diff reads from the aquastat.

Yes the gauge may not be accurate. Basically I believe the hi should be 180F, LO 150F, and diff 20Ffor tankless coil settings.

Mike NJ
 
  #6  
Old 01-25-12, 10:12 AM
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The HL is set to 190 with HDF of 10.

The LL is set to 170 with e LDF of 10.


They had replaced a weak transformer on the burner also... could there be something there I should look for? Wired wrong etc?

Thanks
 
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Old 01-25-12, 11:00 AM
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There should be a diff setting also. Not just the hi or lo diff. That diff is the one that holds the circ off longer during HW use.

Mike NJ
 
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Old 01-25-12, 01:39 PM
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Here is the link to the astat I have. I dont see any diff. setting like you are asking for. I know what you want as it was on my old astat. This one is digital and after scrolling through all the readouts there is only a high and a low diff.

http://customer.honeywell.com/techli...it/68-0281.pdf
 
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Old 01-25-12, 02:22 PM
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In addition to my last post I noticed that when the burner is firing for hot water the temp is slowly going down on the guage. This has never happened before..could the tech have not adjusted the burn correctly and therefore not heating the coild correctly?
Hello,
Does the boiler have any trouble haeting the houe?
Especially when it was down in the single numbers a week or so ago?

It would be normal for the temp to go down some when zones call and the cold water returns into the boiler, but it should catch up pretty quick.

170 is mega hot for domestic water.
I'm waiting for pics. Is there a mixing valve for the hot water?

What type/size shower head is it?
Old style, new - energy saving style?

Peter
 
  #10  
Old 01-25-12, 02:49 PM
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I dont believe there is a problem with the astat. They just changed it out 2 weeks ago as the old one was doing the same and they thought that was the problem. Besides when the boiler fires the boiler temp isnt increasing anyways when the water is running. This isnt scalding hot water out of the tap either mind you, its a warm shower and goes after a minute....otehr times it is perfectly fine. Yes it has a mixing valve off of the coil. This has been fine for 6 years with the setting exactly the same. I dont think the coil is going either as this only happens now and then and when i go down there the boiler is firing but temp on the guage is really low.

Also I noticed that when the call for hot water comes... the boiler fires but the temp of the boiler never seems to rise when the water is running. It only does when it is shut off. I also noticed this when there is a call from the tstat. The boiler fires but the boiler temp never rises until the tstat turns off. If anything i can see the temp guage fall slightly as the water is running.

When the hot water runs out the outlet on the coil is cold...even if the boiler is firing. Its not a shower head issue either.

The heat in the house is fine...never lost heat or had a problem with it not heating especially during the coldest days. The hot water was never a problem either until the tech gave the boiler a tune. Even b4 this tune i watched the temp guage climb when the hot water or heat was on. (not to mention that the tech blew oil all over the utility room. Not sure what he did but when he left i went down there and there was oil mist on the ceiling ground wall. Fun for me to clean.)

I still beleive something happened during the tune and sometimes the boiler wont fire causing the temp to drop. Could the boiler not be firing correctly? Could their be something with the transformer on the burner they changed causing this?

As i mentioned b4 i was down there and i heard the boiler click as if the tstat called for heat and fired for about 4 seconds and then turned off.
 
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Old 01-25-12, 03:45 PM
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To go along with my last post..

I just was running the hot water at the sink... went down and observed the following at the astat readout.

ZOne was on....temp at like 185. Circ kicked off bc of hot water demand. Temp fell down to like 155 were it held steady untill i shut the water off. Temp then climbed up circ and zone kicked back on.

Why is it not heating up past 155 when water is running at one faucet? Could i be getting a bad burn? This doesnt seem right.
 
  #12  
Old 01-25-12, 03:56 PM
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Hello Hammer,
Tough one.
If the boiler can heat the house in the coldest weather, i don't see how it can be a firing issue. But maybe it is..

Yes it is possible they put in a smaller nozzle.
Is there a service tag with tune up numbers on it?

The part about oil all over the place, bothers me greatly.
I would expect the the tech's company to be responsable for the clean up. They made the mess.

Suggest you find another service outfit.
After you call them back and complain about "what they did to your hot water"
Did you pay them?

Peter
 
  #13  
Old 01-25-12, 06:08 PM
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I think we may be onto something with the nozzle. Looking over my paper work it seems that the nozzle in the past have been mostly .85 X 70B. Looks like the last time was a .75 X 70B. Could this smaller flame be the culprit?

Also any idea to why the boiler would fire for only about a few seconds at a time? This doesnt seem right either? And again it doesnt do this all the time.

AI have a service contract with the company and have for the last 6 years, so I dont get any charges for calls....or for most parts. They have been a good company...except for the last time with the oil spray and I didnt tell them they broke my hot water..... I gave them a call and they are coming back out again on friday, and hopefully the responses I get on here will help us figure this out!



Thanks again for everyones input it is greatly appreciated!
 
  #14  
Old 01-25-12, 06:18 PM
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Does it say what the pump pressure is?
Also, curious about the stack temps.

Going from a 85 to a 75 is significant for sure.


The few seconds firing can be normal.
It happens on my stuff a few times+ a day.
Usually it is when a zone is calling, the burner goes thru a cycle and the zone is still calling.
The room is heating up but the T'stat is not quite satisfied .
The burner fires again.
But all of a sudden the damm T'stat is satisfied and the whole boiler/burner shuts off.
It happens.
Probably something similar for you.


Peter
 
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Old 01-25-12, 06:36 PM
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Temp fell down to like 155 were it held steady untill i shut the water off.

That seems good no? Full hot @ 2.5 gpm from a sink right?

Through a mixing valve on there to limit the temp and I would say golden...

Trooper is good at the coil stuff possible he will chime in here.

To save oil also I think the preferred temps are

Hi 180

Lo 150 LDF 20. I believe with that setting the circ will hold off until 160 on a DHW call

Mike NJ.
 
  #16  
Old 01-25-12, 06:37 PM
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The last time they were out and used the 75 the stack temp is 449? I dont see any pressure listed on the write up.

I only see one other time they used a 75 nozzle and that was in january of 2010. The write up says in bold NOTE: Pump pressure is at 160 with .75.70B nozzle. There is not note of stack temp.

The rest of the receipts are all .85 nozzle (except for the last time they were out.) Only one of the 85 nozzle receipts states a stack temp of 400 with no pressure indicated.

I do know that a few times ago they turned up the time the power venter ran. Its seems to run for a lonnnnnnng time now.

Any ideas to why sometimes I go down there and the temp is around 100....as if it didnt fire? Or could the hot water have brought this temp down so low from a shower? The more i think about it the more i am leaning toward this nozzle and they way he set it up esp. since it was fine before the "tune".
 
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Old 01-25-12, 06:57 PM
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Any ideas to why sometimes I go down there and the temp is around 100....as if it didnt fire? Or could the hot water have brought this temp down so low from a shower?
When it is at 100, the burner should be firing, if i understand that aquastat correctly.
Is it?

Peter
 
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Old 01-25-12, 07:40 PM
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Yes it is firing, and the temp is slowly rising. I am just wondering if it didnt fire when it should have for some reason. It is almost as if the astat is bad.... but then again it is a brand new one and still acting like the old one.

Are there any other electrical pieces that I could check could cause it to not fire when the call for heat comes on?

I do think the nozzle and burn has to do with this. Never in 6 years has the temp dropped so low as it has after this last tune....except when we lost power! I dont think the 70 nozzle can keep up. Like i said even when the tstat kicks on the boiler temp stays steady when it fires. It never climbs until the tstat kicks off. I dont believe it worked so hard in the past for the heat.
 
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Old 01-25-12, 10:05 PM
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Your oil bills must be ugly.
IMO you might be far ahead with an inexpensive electric hot water heater.
How much is a kw of electricity, down your way?
Then you could keep a smaller nozzle, and set that beast to run at cooler temps, with a much lower warm start.
Maybe shut it down for the summer.

Peter
 
  #20  
Old 01-26-12, 05:47 AM
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I cant stess enough that this doesnt happen every time either. It is very intermittent. For example, the last time it happened was two days ago. No one had used the sinks, showers or any water for hours leading up to the last lost (so its not like I just ran out of the hot water from overuse), then I jump in the shower and 30 seconds later no hot water?

Anyone with ideas onto what would cause the boiler to not kick on and maintain the internal temp besides the astat? Could something else electrical be going... wired wrong, etc?

How about a partial clog in the power venter sensor tube? I know my boiler wouldnt fire one time bc of a total clog and had shut down and the tube had to be cleaned out.
 
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Old 01-26-12, 04:47 PM
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Transformer

I have been keeping an eye on the boiler and temps when it fires to see where I am at. Today was sitting at home. I heard the boiler fire. I checked the astat temp and it was reading a boiler temp of 154 and climbing. The LL is set to 170 with a 10 differential so there is def. a problem here and I dont think it is hot water related.

As the tech only switched out the transformer "as it was weak" as well as clean the boiler then this all started the problems. I started to read about transformers on the burner and this may be the culprit. Could the electrodes be incorrectly set up as this was the only thing the tech switched out and now I have this problem causing it not to fire sometimes? What about a dirty photocell. Dont forget the tech sprayed oil all over the place could the photocell be partially blocked?

I know its not the astat as this is the second new one and still not kicking on.
 
  #22  
Old 01-26-12, 04:53 PM
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The domestic hot water coil could be clogged with sediment, either inside the coil pipe or around the coil. This slows down the heating and the water could exit the coil before coming to the desired temperature.

For domestic water heating the aquastat in the boiler should turn on the burner as needed without any room thermostats calling for heat. Sometimes there may be a second aquastat to keep the burner running until a higher burner cutoff temperature is reached when room thermostats are calling for heat.
 
  #23  
Old 01-26-12, 05:16 PM
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A zone could have called and dumped 65 degree water into the boiler, lowering the average temp, even with the burner on.
How long did it take to heat back up?



Peter
 
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Old 01-26-12, 06:58 PM
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Peter think your right on that one, with the 65 degree zone water entering. It didnt seem to take that long to heat back up and i could see the temp rising as a degree a few seconds.

I do still notice that one zone for downstairs seems to always be allowing hot water through even when the zone calls for heat. The radiators are always "warm" when the heat is off. When the heat is on they are hot. The upstairs zone seems good.. radiators cool when zone is off and hot when on. I'll point that out to the tech too. Who knows maybe the constant leak of water is cooling the boiler down and when it fires for domestic allowing some heat to flow to the baseboard. I did notice that when the upstairs calls for heat the 1st floor zone pipe after the zone valve does get alot hotter even when the zone is closed. Hopefully it is only the electrical part of the valve and no cutting sweating is involved.

Guy is coming out tmrrw and I appreciate everyones input. If they find anything out i'll post it for anyone who might come across this PITA.

Allan: I dont think its sediment as I can blast the shower right now for as long as I want and it steams away. This only happens now and then... its extremely frustrating....again maybe the zone is getting stuck open occasionally?

Thanks again for everyones input.
 
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Old 01-27-12, 02:17 PM
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So after a long talk with the tech we switched out the mixing valve. He seems that it may have been shot and allowing cold to mix in. It was turned as hot as it could go and still wasnt that hot. Water out of the tap seems to be much hotter now.

Also he changed out the 75 back to the factory recommended 85 nozzle with the correct pressure.

I left the sink running full blast on hot and watched the temp drop down to 160....burner tunred on and dropped to about 155 then climbed up to the set 170 and off it went so it seems to be good.

I dont know why this astat though does not have a differential setting to bring the water up past 170.....
 
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Old 01-27-12, 03:56 PM
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I dont know why this astat though does not have a differential setting to bring the water up past 170
That's the "LDF" setting...

When the boiler water reaches the LOW LIMIT minus the LOW DIFF it will disable the circulator and fire the burner.

When the water hits the LOW LIMIT setting the burner will shut off and the circ will be re-enabled to run.

(note: this is DIFFERENT than the way the older 8124 series of controls operated)
 
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Old 01-27-12, 05:45 PM
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Mentioned the mixing valve a million posts back, but you told me it could not be the problem.


Hope it stays ok for you Hammer.

Peter
 
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Old 02-02-12, 07:17 AM
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After having this new setup run and watching the temp I am pretty confident that the problem was not with the mixing valve but with the smaller nozzle. Peter remember that I said the outlet from the coil was cold even before it reached the mixing valve (when the problems occured) so I am still skeptical that was the problem. (The tech switched it out as it was covered and was just another thing to cross off the list.)

After putting in the correct nozzle and setting the pressure to factory specs the burner runs less.... does not smell of oil or exhaust and you can actually see the temp rise on the guage now while the circulators are running and burner is firing. It used to stay at one temp when firing untill the circulator kicked off then would rise. So basically every time the heat was on it was firing. Now it heats up nice and off it goes. Even when blasting hot water it heats up and shuts off. I believe the smaller nozzle wasnt producing enough "heat" that was needed and couldnt keep up causing the temps to slowly fall....especially if both zones had just dumped and then the hot water was turned on causing it to seem intermitent.

Thanks again! Hopfeully this helps someone in the future!
 
  #29  
Old 05-11-12, 07:32 PM
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Solved...finally

To anyone who has a direct vent system.... Make sure when they perform your annual clean they clean the tube that goes to the sensor on the direct vent fan. After months of intermintently loosing hot water it was found that occasiannly the boiler wouldnt fire (never lost heat though....). The power venter would run and run and take forever for the boiler to fire....this would cause water temp to drop when hot water was running... it wouldnt effect heating but shower temps could never recover. After using compressed air to clean out the tube that runs to the fan and sensor all is good and tghe boiler fires up and no constant running of the powerventer. Big headache... small problem.


That said...even having found the problem have now switched to indirect 40 gallon tank And the diff between coil is hands down much better. NEver ending hot water and boiler barely runs. Def worth the investment.
 
  #30  
Old 05-31-12, 06:38 PM
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Good tip, my service guy warned me of this and although he cleans it during service he told me to take it out and clean it if the vent came on and the boiler does not fire in a timely manner.
The only issue I have had with my indirect is having to clean the outside of the coil due to buildup from my well water. I have since installed another filter and rigged up a piece of 1/4 inch copper tubing on a hose which I stick thought the pressure relief hole. I hammered the end flat and drilled 2 very small holes in the tube. This provides a nice high pressure stream from the end and the holes to clean the coil. Works slick and no need to drain the boiler to remove the coil and clean it.
 
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