Utica \Boiler mate Short Cycling

TommyD

OK So I have to admit up front that I am just a home owner and dont have any formal traing as a furnace technician.  I am not asking advice so I can fix my issue myself but just want to fully understand what could be the issue so I can be infomed when I deal with my Oil Company.

Here is the problem as I see it:  20 year old Utica SF-3100WT\Amtrol Boiler Mate 41 Gal.  Now I heat my house 100% with wood and all zones are set to 50 degrees so the only draw on the Utica should be the Amtrol hotwater heater.  When I pull DHW after about 5 min the boiler comes on which make sense - the boiler temp goes down to about 140 and then climbs back to 180 and shuts off.  The aquastat is set at 170\120 with a diff of 25 (honeywell 8124a).  Now my issue is that nearly EVERY hour the boiler will come on and run for approximately 2 min then shut off even during the middle of the night and all summer long as well.  I have noticed that when this happens the boiler temp is about 180 and if I put my hand on the hotwater supply line to the Amtrol- the pipe is only warm not hot so I dont think it is the water heater calling for the boiler to turn on.    During these every hour events I also run down there and feel the pipes on the other side of all the zone valves and they are not hot so I dont think the thermostats are triggering the boiler either or I would assume the taco valve would open and the pipes on the other side of it would be hot...

I am a VERY handy guy and fix most everything that needs to be done with my house- also a software developer so the logical side of my mind can not really figure out what is going on.  I have done enough research to know that "maybe" the boiler was at one time set up for a tankless DHW and then the Indirect water heater was added and the hourly cycle is to keep the boiler heated for old tankless coil setup...but this is where my head starts to spin and loose confidence I know what is going on.  The main reason for my concern is that I am burning WAY to much oil for the amount of hot water I am using - only me and my wife so we do not have tons of kids using hot water all day long. and I burning about 500-600 gal per year!!!!

Is there any logical reason why the boiler would fire even though the temp of the boiler is about 180 degrees???  Also if anyone has a potential solution that would help me talk to the repair company inteligently that would be awesome.  Also I know the oil company has professional and this is their job but my confidence is kind of low as the last time they were here I asked them questions about this all they could say was the old mercury tstats could be bad...

Thanks in advance for any advise you could offer.

Tom

heatpro02920

tankless boiler with indirect?

Obviously this boiler had an internal tankless at some time? {try unhooking one of the TT to that control, {as long as your indirect isnt zone valved or on a zone control} I would switch the aquastat control to start... Why maintain at all, run cold start.... But your boiler is old and you can run into condensation cold return temps ect...



Honeywell L7248 should do it, {I may have the number wrong that popped in there first, and they change these things all the time...} there is a way to turn that to cold start your tech will know how to do it {search aquastat number and blue wire should be instructions on the web}.... But again have the boiler checked out dont want any new leaks..



I would keep the boiler around 160 to run just that indirect...

billtwocase

Utica

I have the same boiler and indirect in my own house. It maintains about 100 degrees, and high of 180. it does not run every hour. I would look into replacing a zone valve head. Something is running this up to hi limit, but mot sending heat around. Bad end switch in a power head? If the Amtrol wasn't heating, then something else brought it on. I would turn your low limit all the way down. Although you can turn that control into a cold start control, I wouldn't. What control is on your Amtrol?  Smart or Z ? How is it zoned? You have a 3 section cast iron boiler that has a tankless coil that is not in use anymore. It is not set up to preheat the tanks cold water inlet, is it? Stack damper would also be a good investment. It will help to stop the rapid stand-by temp loss if it is chimney vented. Also pics are also a good thing. Also water or antifreeze in it?

TommyD

Response

Bill - is there a way to determine which zone valve could be bad?  Is there some sort of test I can do with my multi-meter or a manual test of some sort?  Would it help to disconnect the various thermostats one at a time to determine the zone with a possible problem?   I will take some pictures asap to give more information.  One of your questions was " It is not set up to preheat the tanks cold water inlet, is it?" Can you tell me how I can research this to give you an answer? 

I really appreciate the guidance from all...  One more thing to consider - I have had the house for about 10 years and this is not a new occurance - I am just getting around to obsessing about it now that oil prices are so high :-)

Thanks again - Tom

Paul48

Accuracy

The accuracy of the aquastat may be off a little, but it should not be maintaining at high limit, which is what it sounds like. The high limit has a fixed differential of 10*, and once the boiler drops the 10 it fires, then goes back to high limit and shuts down. Honeywell's site is down for maintenance so I can't pull up the schematic, and try to figure out how it could happen.

mark schofield

troubleshoot

If you heat completely with wood and don't need the heating zones, could you try isolating the problem by disconnecting stat #1, see what happens, then zv # 1, ect; until all the stats and valves have been removed in sequence from the system. if the problem goes away during this process it might be one of these. Please post when you figure it out.

TommyD

Troubleshooting follow up ?

Mark - Can you give me some basic instructions on how to isolate the zone ?  I assume the proper way to isolate the tstat is to simply take the screws out and remove the actual round tstat assembly from the wall bracket ( essentially just leaving the mounting bracked with red and white wires on the wall with no dial assemby) but isolating the zone - I am thinking  you mean to just remove one of the wires on the taco zone valve, but which color wire will turn that valve off?  Is it the red one?

Again thanks so much for all of the guidance on my question.

Tom D

billtwocase

wires

Tom, I would remove only the #3 wire on the power head. It is the one closest to the the heating pipe that the base is plumbed to. This way if it does need to heat, #1 will power the head, and you will get gravity heat thru that zone. #2 & #3 are the end switch or points, if the head is green, to make your "T-T" circuit for the aquastat to run to high limit. Disconnecting #3 on the head will disable that possibility, and help to isolate the problem. I would also check all the heads for a wire shorting between #2 & #3 . This will have the same affect.

TommyD

Add pictures to help with investigation

Guys - I first off I want to say how appreciative I am to get your guidance, I am learning a TON in the process.

Here are some pictures of my set up to help with the investigation:

First thing I noticed is that all zone valves are daisy chained to together on the red #3 wire so I am unsure how to isolate them one by one if the zones are all linked together - is this standard set up?  Anyway here are a bunch of pictures to see if it helps show you the situation I have.

Based on the pictures what should my next investigation step be?

Tom D

billtwocase

#3 wire

Tom, by loosening the terminal screw, and pulling the wire off, that will take that zone out of the mix. If you hear the relay in the control drop out immediately, and that zone wasn't actually "calling" for heat, that would be the culprit head. If the #3 wire is not looped on all heads, you must wire nut it to make sure all the other heads are still in the mix. You have a lot of zones there. Is there a wire on Z-R in your aquastat? That should be from your Amtrol. Could also be the problem

billtwocase

looks like it to me

from the pic, looks like the red wire is tied into Z-R. Also looks like the relay is pulled in on the control. I'm thinking Amtrol is not wired right. If you had a bad power head all these years, your circ would be fried. The relay not only overrides the low limit, it also powers the circulator. My bet would be the red wire is tied into the L-1 at the tank. Z-1 only activates for hi limit, and won't power the heating circ.

TommyD

additional information

Bill - first I can confirm that the there is a red wire connected to the z-r terminal on the aquastat - when I follow that back it goes to the connection box in the Amtol - but there is no listing of L1 of any sort on the Amtrol.  Another bit of information to your first post - I disconnected the red wire on the #5 zone - the last one in the daisy chain(on the left most side of the image above) and I DEFINATELY heard something from the aquastat - to the point I was a little nervous I had shorted somthing out!!!  I left it disconnected though but it still short cycled some time later.  With regards to the circ pump - I did have something replaced last year by the oil company because I was not getting heat to my 3 floor zone.  If you look at the picture of the front of the boiler with the damper showing - the part replaced last year is right behind the shiny brass relief valve - I am not sure if that is the circ pump you mentioned.  Now as said previously I very seldom turn the heat on and can confirm that the number 4 zone goes to a small modine shop heater that has not been turned on in years - and the number 5 zone (the last one in the daisy chain I disconnected) is for baseboard heat in a my basement tv room - this heat has not been on for 2-3 years min.  Both zone 4 and 5 are very short runs to the boiler.

Thanks again man - I really appreciate it.

Tom D

billtwocase

L-1

Tom, the 3 wires that I see going out of the left side of the control are black, which is your L-1, white, which is L-2, and the red is is power coming back into the control box from the Amtrol, and ties into Z-R to override the low limit, or send power thru a limit if cold start. The sound you heard in the control was either you touching #2 & #3, or that might have been the "clapper" dropping out meaning that is the bad head, or it was calling for heat at the time of test.

TommyD

one more thing

Bill - I located what I "think" is the relay on the amtrol - it is inside the access door under the contol knob - I traced the the red wire going to the Z-R terminal on the aquastat to the "yellow" wire on the relay.  I do not know if that helps?  Also I found the wiring diagram in the manual for the amtrol and it seems the relay on the tank is an R845A - again I dont know if that helps you?

Also one more thing I have noticed - the boiler is ALWAYs at or very close to 180 - unless there is hot water running somewhere.

Tom D

billtwocase

also

looks like a feed valve was replaced behind the hivent? That would not cause too much heat. It was possibly leaking, or there was no pressure on the boiler. The circulator would most likely be in back of that boiler. Follow your return piping down, there it will be. I don't see that it was installed to pump away

TommyD

confirmation

Bill - I can confirm that the L1 and L2 wires going to the amtrol are as you pointed out - Black on L1 and White on L2.  Any suggestions now?  The zone valve that I heard the noise from is still has the red #3 disconnected and the boiler has short cycled about 3 times since....

TomD

billtwocase

can't be

sounds like the "Z" control, and it should have it's own relay built in. Is the an external relay there also? Shouldn't be, unless they have tied the 2 black wires from the thermostat into "T-T" on a switching relay, and have properly wired an RA845

billtwocase

have you

tried to move the levers on each zone valve head? If they move easily towards the piping, then a thermostat has sent power to it

TommyD

zone heads

Bill - all zone heads have a lot of resistance when I try to move them twords the pipe.  Also including a pic of the inside of the amtrol - this is the relay I think - there does not seem to be any other relay attached to the tank.  Also I can confirm that the TT in the aquastat has its red and white wires going to the first zone valve and are connected white to #2 and red to #3.

Thanks again for taking the time to help with my investigation.

TomD

TommyD

AHHH HAAAA moment

Bill - I just noticed the red wire going dasiy chaining to vzone numer 5 has a chafe and copper is exposed - when I jiggle the wire I hear a click and a humming that I think is the circ pump.  Now I have straightened out the wire and dont hear the hum at all ... Do you think this chafe in the wire could be a problem?

TomD

billtwocase

from here

the only other test is to disconnect the wire from Z-R. It is high voltage, and I would recommend an electrician from here. You seem capable, but I would rather you net get "zapped" . I would say either wired wrong, or bad relay for Amtrol. It is also best to shut of switches when working with wiring.

TommyD

chaffed wire Red #3

This is the chaffed wire on zone #5 - it was coiled up and when I straighted it out I do not hear the humming from the circ pump any more...  should I just cut the bad spot out and reconnect?

Tom D

billtwocase

yes

repair it. Cut, strip, and wire nut it. Is it severed now?

TommyD

more chaffed wire

Bill - I just noticed this LONG chaffing on the white wire that was right nest to the chaffe on the red wire... This may have been shorting out some how??  Now both of these are just jumper wires from one zone valve to the next - should I just cut out the bad spots and reconnect?

TomD

billtwocase

just seperate them for now

those 2 are for your end switches. Then monitor it

billtwocase

I'll check back later

let us know how it goes. Be back on later tonite.  Good luck

TommyD

Success !!!

Guys

All I can say is THANK YOU VERY MUCH !!!  The help that everyone gave to a perfect stranger is just awesome.  I seperated the two chaffed wires over 3 hours ago and the boiler has not short cycled once!!!  The boiler temp is now staying way below 180 around in the 120-140 range and only comes on when I pull DHW.  My last question to you all is what should I set the Aquastat HI \ Low \ and Diff values to now that things seem to be working better?

Thanks again for the guidance everyone gave me on this issue.

Tom D

billtwocase

glad to hear it

as far as the low limit, turn it all the way down.No need for that boiler to maintain a temp above 100 degrees. I don't like cold start, but you can easily set that control to do so. Because there is an indirect, the boiler will always have some temp on it anyway. Good luck

TommyD

24 hours later

Well after 24 hours I can confirm that the problem is SOLVED!!  the only time the boiler comes on now if when I am calling for DHW.  Hopefully I will save a little when the oil truck comes now.....

I have set the aquastat at 160 \ 120 (120 is the lowest I can set to)  What should the Diff be set to or does it not matter with the Amtrol hooked up?

Thanks again for everyones help - as I read back through the entire thread I think it was little bits and pieces for everyones responses that help me find the issue.

Tom D