boiler not running when tsat calls for heat?
#1
01-15-09, 06:57 AM
boiler not running when tsat calls for heat?
this is happening intermittingly.
I have a Weil Mclain CGI in a 3 zone hydro air system. I also have Honeywell 7day programmable tsats for all 3 zones. The problem is occasionally I will notice the house is cold. I can see the tsats are all reading system on however the boiler is dead silent - circ motors not running, exhaust fan not running, etc. I also noticed the relay box seems to be dead as well. none of the LEDs are lit up as they should when the individual zones are "on". In these cases if I flip the switch to shut power to the boiler (I believe this also powers the relay box) leaving it off for around 15 seconds. I flip it back on and presto every thing comes to life. This has been happening for years, typically only once, maybe twice a heating season. this season it is occurring with increasing frequency to the point where it is happening almost every night! I have had 2 different boiler professionals look into this over the years however they both told me they can't diagnose the situation unless they see it happening for themselves. i can't recreate this at will and i can't leave it off cause I have 3 young kids. Any ideas on where to look? could this be a problem with the way the tsats communicate with the relay box? i used to have the old round tsats and the problem occurred with them as well.
Thanks,
I have a Weil Mclain CGI in a 3 zone hydro air system. I also have Honeywell 7day programmable tsats for all 3 zones. The problem is occasionally I will notice the house is cold. I can see the tsats are all reading system on however the boiler is dead silent - circ motors not running, exhaust fan not running, etc. I also noticed the relay box seems to be dead as well. none of the LEDs are lit up as they should when the individual zones are "on". In these cases if I flip the switch to shut power to the boiler (I believe this also powers the relay box) leaving it off for around 15 seconds. I flip it back on and presto every thing comes to life. This has been happening for years, typically only once, maybe twice a heating season. this season it is occurring with increasing frequency to the point where it is happening almost every night! I have had 2 different boiler professionals look into this over the years however they both told me they can't diagnose the situation unless they see it happening for themselves. i can't recreate this at will and i can't leave it off cause I have 3 young kids. Any ideas on where to look? could this be a problem with the way the tsats communicate with the relay box? i used to have the old round tsats and the problem occurred with them as well.
Thanks,
#2
01-15-09, 02:02 PM
you mentioned the stats were indicating call for heat on all 3 zones,but did you notice if the zone valves had swung to open position?at the zone vlve can you manually swing it open with that push bar to simulate the stat calling.try one at a time......manually open it,and get the boiler to cycle on then set it back to normal position.then try each of the others this will prove that the circuit closusure(end switch within the zone valve is true).do you have a 2nd transformer mounted on the boiler or is the one in the relay box the only one(important).the reason i am asking is that you need a true 24Vs to power those zone valves from the round stat days....and even more VA(voltamps) to power the newer digitals......if your working off the relay box TR for the whole show you might need to add a seperate TR for the valves and the stats so the relay TR only runs the ignitor/gas valve and the circulator relay within the boiler.last question...do you have an automatic(motorized)vent damper on the flue?
#3
01-15-09, 04:25 PM
If EVERYTHING seems dead, and flipping the power switch to the boiler fixes it, it's possible that the power switch itself is defective.
In other words, if that is the ONLY thing you touch to get it working, and it cures the problem EVERY time, I would replace that switch FIRST... or, at least examine the connections to that switch for loose connections. SHUT OFF THE CIRCUIT BREAKER IN THE PANEL FIRST!
In other words, if that is the ONLY thing you touch to get it working, and it cures the problem EVERY time, I would replace that switch FIRST... or, at least examine the connections to that switch for loose connections. SHUT OFF THE CIRCUIT BREAKER IN THE PANEL FIRST!
#4
01-15-09, 06:28 PM
Sminker,
I don't have zone valves. All I have are three circulating motors on the return and 3 flowcheck valves on the supply. this is a direct vent high efficiency unit so no flue damper, and no low limit switch either. it just goes stone cold until heat is needed.
I do seem to have only one 24v tr in the relay box but is that still an issue since I don't have zone valves? I don't think anything is digital as the system is 10yrs old and pretty basic.
NJ Trooper,
there are 2 shutoff switches. one emergency at the top of the basement stairs and one on the boiler. I pulled out both and looking at them they appear to be in good working order. these switches are never disturbed until I need to hit them when the problem arises. the boiler was running at the time so I gave them a good wiggle and the boiler stayed running with no issues.
I don't have zone valves. All I have are three circulating motors on the return and 3 flowcheck valves on the supply. this is a direct vent high efficiency unit so no flue damper, and no low limit switch either. it just goes stone cold until heat is needed.
I do seem to have only one 24v tr in the relay box but is that still an issue since I don't have zone valves? I don't think anything is digital as the system is 10yrs old and pretty basic.
NJ Trooper,
there are 2 shutoff switches. one emergency at the top of the basement stairs and one on the boiler. I pulled out both and looking at them they appear to be in good working order. these switches are never disturbed until I need to hit them when the problem arises. the boiler was running at the time so I gave them a good wiggle and the boiler stayed running with no issues.
#5
01-15-09, 06:36 PM
Steve, do you own a multimeter and know how to use it to measure AC voltage?
Just to be sure ... you say NOTHING happens, correct? NO circulator running, NO ignition spark, NO pilot, NOTHING... correct? I know you said this in your first post, I just want to hear it again is all!
If so, what you might do is locate where the 120 VAC is connected to the system and the next time you experience the problem, before you turn off and back on, while the boiler is 'dead', verify whether or not you have line voltage at that point.
99% of troubleshooting is visual... a close inspection of ALL the wiring might reveal a loose connection someplace.
Is your boiler a SERIES 1 or a SERIES 2 ?
Do you have the manual for it?
Just to be sure ... you say NOTHING happens, correct? NO circulator running, NO ignition spark, NO pilot, NOTHING... correct? I know you said this in your first post, I just want to hear it again is all!
If so, what you might do is locate where the 120 VAC is connected to the system and the next time you experience the problem, before you turn off and back on, while the boiler is 'dead', verify whether or not you have line voltage at that point.
99% of troubleshooting is visual... a close inspection of ALL the wiring might reveal a loose connection someplace.
Is your boiler a SERIES 1 or a SERIES 2 ?
Do you have the manual for it?
#9
01-15-09, 07:06 PM
There's a trouble shooting flow chart toward the end of the manual, see if you can follow those steps for the condition that best suits your problem ... of course, if you find that the 120VAC is not there at the input... then you have to go the other direction, toward the breaker panel...
#10
01-15-09, 07:22 PM
If you find that you have 120 VAC present when the boiler is 'out', there's a very good possibility that it is 'locked out' because of a problem with the PRESSURE SWITCH (and a couple other things) ... it will come OUT of lockout :
After 1 hour.
If the thermostat is OPENED and then CLOSED again.
AC POWER is removed for 45 seconds.
If it comes out of lockout after 1 hour and finds the same problem, it will lockout again.
Next time it happens, after you check for 120VAC in the Jbox on the side, try turning the t'stat all the way down, wait a minute and turn it back up and see if it fires.
After 1 hour.
If the thermostat is OPENED and then CLOSED again.
AC POWER is removed for 45 seconds.
If it comes out of lockout after 1 hour and finds the same problem, it will lockout again.
Next time it happens, after you check for 120VAC in the Jbox on the side, try turning the t'stat all the way down, wait a minute and turn it back up and see if it fires.
#11
01-16-09, 04:35 AM
so the stat runs the circulator for the zone,and the relay related to each pump total 3 circ.relays in the box powered by one TR.the reason i mentioned your digital stat update is the draw on that TR in the relay box as the only source of control voltage.so the load on the TR is the relays,the gas valve/ignition and the stats.QUICK CHECK....remove 2 of the stats off the subbases,and just run the single stat as if it was one zone/one circ. to see if you get a consistant cycle.the only thing common to the 3 stats,3 circ relays and the boiler itself is that boxed TR ....check on the inside cover if it states the VA for the transformer.
#12
01-16-09, 04:53 AM
so the stat runs the circulator for the zone,and the relay related to each pump total 3 circ.relays in the box powered by one TR.the reason i mentioned your digital stat update is the draw on that TR in the relay box as the only source of control voltage.so the load on the TR is the relays,the gas valve/ignition and the stats.QUICK CHECK....remove 2 of the stats off the subbases,and just run the single stat as if it was one zone/one circ. to see if you get a consistant cycle.the only thing common to the 3 stats,3 circ relays and the boiler itself is that boxed TR ....check on the inside cover if it states the VA for the transformer.
#13
01-16-09, 05:47 AM
NJ Trooper,
of course, I didn't have the problem yet but if the boiler is locked out what would you expect to see inside the relay box? would the zones LEDs be lit or dead? In my case the box seems completely dead. i will try to restart it via the tsat as well.
oh, its a series 1.
sminker,
i was incorrect. looks like the boiler has its own transformer, at least according to the manual. haven't had the opportunity to see it first hand as I'm at work. Not sure if i can live without the 2 zones for that test. gotta keep the kids and wife warm. what total va would you expect is needed to run this kind of setup?
of course, I didn't have the problem yet but if the boiler is locked out what would you expect to see inside the relay box? would the zones LEDs be lit or dead? In my case the box seems completely dead. i will try to restart it via the tsat as well.
oh, its a series 1.
sminker,
i was incorrect. looks like the boiler has its own transformer, at least according to the manual. haven't had the opportunity to see it first hand as I'm at work. Not sure if i can live without the 2 zones for that test. gotta keep the kids and wife warm. what total va would you expect is needed to run this kind of setup?
#14
01-16-09, 03:00 PM
Steve, if my first suspicion that the power switch is intermittent, you won't see 120VAC inside the j-box, and there won't be any LED's or anything on...
If when it's not running, you have ANY indication of power, such as an LED on a control, then chances are pretty good that the power is there, but the controls are locked out.
Since one of the 'resets' for a lockout IS cycling the AC power, there is a strong possibility that it is locked out. I'm not sure if the Series 1 has the same functionality upon lockout as the series 2 ... and those details about it were from the series 2 manual... I'll look at the other manual later.
[It's later, and I've looked at the other manual. I can't read the schematic in the PDF file, it's a very poor quality scan... I do NOT see in the manual where it mentions the information on the lockouts that is mentioned in the series 2 manual.]
I think it's very possible that the pressure switch is somehow flakey... and locking you out (if it's not a total loss of power).
If when it's not running, you have ANY indication of power, such as an LED on a control, then chances are pretty good that the power is there, but the controls are locked out.
Since one of the 'resets' for a lockout IS cycling the AC power, there is a strong possibility that it is locked out. I'm not sure if the Series 1 has the same functionality upon lockout as the series 2 ... and those details about it were from the series 2 manual... I'll look at the other manual later.
[It's later, and I've looked at the other manual. I can't read the schematic in the PDF file, it's a very poor quality scan... I do NOT see in the manual where it mentions the information on the lockouts that is mentioned in the series 2 manual.]
I think it's very possible that the pressure switch is somehow flakey... and locking you out (if it's not a total loss of power).
Last edited by NJT; 01-16-09 at 03:34 PM.
#15
01-19-09, 10:12 AM
so i was able to restart the boiler by turning off the thermostats and turning one of them back on. so i guess the boiler is locking out. i don't have a manometer so do you think I should just buy a new pressure switch?
Thanks,
Steve
Thanks,
Steve
#16
01-19-09, 02:56 PM
I would first see if you can check the ends of the tubing where they insert into the draft inducer to make sure there is no dust/dirt plugging the end of the tube.
The other possiblity is that the pressure switch is working fine and doing what it is supposed to be doing (it's a safety control that prevents the boiler firing if there's a problem with the DI), and that the draft inducer isn't spinning up to speed quickly enough... I believe there are oiling ports for that motor? Check the manual and see what it says for service of the inducer motor. I bet it's been a while since they have been oiled.
The other possiblity is that the pressure switch is working fine and doing what it is supposed to be doing (it's a safety control that prevents the boiler firing if there's a problem with the DI), and that the draft inducer isn't spinning up to speed quickly enough... I believe there are oiling ports for that motor? Check the manual and see what it says for service of the inducer motor. I bet it's been a while since they have been oiled.
#17
02-12-09, 08:50 AM
I thought I'd give an update on the ordeal,
after verifying the draft inducer tubes were clear, replacing the pressure differential sensor, the pilot assembly, the ignition module and the transformer relay the problem STILL was not fixed. I had a new plumber and electrician do the above mentioned replacements. before this, the electrician completely re-wired the boiler as he thought something wasn't correct with the way the tsats were wired in between the boiler and the Argo box. but that didn't work either.
The problem turned out to be the Argo box itself!!!
I now have a nice 4 zone Taco control box. the house is much more comfortable now that I don't have to keep resetting the boiler.
How common is this?
thanks for your guidance.
after verifying the draft inducer tubes were clear, replacing the pressure differential sensor, the pilot assembly, the ignition module and the transformer relay the problem STILL was not fixed. I had a new plumber and electrician do the above mentioned replacements. before this, the electrician completely re-wired the boiler as he thought something wasn't correct with the way the tsats were wired in between the boiler and the Argo box. but that didn't work either.
The problem turned out to be the Argo box itself!!!
I now have a nice 4 zone Taco control box. the house is much more comfortable now that I don't have to keep resetting the boiler.
How common is this?
thanks for your guidance.
#18
02-12-09, 03:25 PM
I also noticed the relay box seems to be dead as well. none of the LEDs are lit up as they should when the individual zones are "on".
OK, I've lernt a lesson... always ask for a complete equipment list, and pictures... always!
Sorry for the trouble Steve, but glad ya got it fixed up finally!
