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Multiple boiler issues - help needed


Berzy's Avatar
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01-14-18, 12:03 AM   #1 (permalink)  
Multiple boiler issues - help needed

Hey Gang,
Sorry for the length of the post. I have a couple issues and I have posted on other sites before and realize that there is a lot of info needed to paint a picture for someone. I can grab a few pics also if needed.
I'm troubleshooting an issue that is a little out of my comfort zone. Long story short that was suppose to be setup and working on arrival and now I'm stuck in the arctic with an unreliable heating system and no boiler mechanics for many miles. I am working on a Heil oil fired boiler that is working like a charm but has a few issues that are causing it to be unreliable and inefficient. The boiler basically is short cycling and the post purge is running for too long at -35C and has no adjustment with the aquastat on the low temp cut-in. My goal is to increase the time between cycles on/off and decrease post purge time. Hopefully making the unit a bit more efficient.

Here are the details on the boiler and unit:
-Heil HMR model boiler with 4 zone valves\thermos for 4 in-floor heating loops in a 3 BR 2000 sq.ft living unit.

-Beckett burner AFG model and honeywell controller(R7184B) are connected to a low pressure cut-off and and low water cut-off and on to the 120VAC junction box. (no issues there but I'm guessing the Honeywell controller box is underused and my be able to eliminate some useless parts.

- Between the low pressure switch and the burner controller box is a Honeywell aquastat L6081A. I think the white wire should be connected through the unit to allow the aquastat to control the connection on the white(neutral) wire. But I'm not sure and from what I see and read a lot of people jump the White(neutral) together and run the aquastat only off the high temp setting but I do not want to touch this and risk frying my only aquastat. Also I guess that is why my boiler fires when the temp drops 20F below the high time setting. I should mention I have played with the Diff and it is set to 20-25 now. If it is lower it seems the boiler never has a chance to cycle off.

- the glycol is pushed with a pump continuously and a wild loop is in place for when zone valves are not open. Odd thing is it seems like it was run into a Honeywell transformer (RA89 A 1116) which now is bypassed and the wire coming from 120VAC junction box on the wall is removed from the transformer and marretted to the wires running to the pump directly powering the pump. (wondering if this is damaging the pump and if I should just tidy up the wires and add a switch to make it .....safer?) from that transformer was a low voltage wire that appeared to be powering the zone valves and/or slab sensors? not sure but there are 4 other low voltage wires that go into the wall that are not powered because the transformer is no longer in use. The zone valves for the thermostats are powered by a separate very basic transformer block similar to a door bell type. The thermostats are powered by a second one next to it. I'm guessing I can remove that Honeywell transformer and tidy up the wire mess there once my 2 main issues are dealt with.

- the sidewall power venter and damper is powered by a Proving switch or pressure switch Model K07003 (computer board inside says B01131 Dettson) This is the unit that should help adjust the post purge time but I cannot find any info on it or anything inside to adjust like dip-switches, jumpers, dial pots, etc. So I'm assuming that it would need to be replaced but I do not want to order anything until I'm sure it will work. I can not risk having this heating unit down for very long in the harsh arctic temps.


Prob#1 is the sidewall vent has a post purge time of 5.5 min and is pushing all the heat out of the mech room. At -40c that is cooling the room after every cycle. I can not find any information on the unit that would adjust that time. Perhaps it can't be adjusted and needs to be replaced with one that can.

Prob#2 the boiler is short cycling. The Boiler with fire up no problem, run for 3 min and shutdown no problem while the sidewall vent runs another 5 min. Problem seems to be a couple things like the heat loss and cold glycol returning from the heat loops into the unit. But one issue I cannot fix or adjust is the cut-in temp on the aquastat. I can adjust the high temp cutoff which is at 160F but the cut-in low temp seems to always be 20F below the high temp setting. The low temp know has no effect on the boiler but I can hear the clicking near the proper temp compared to the gauges. I believe the aquastat is not wired properly and the low temp adjustment is bypassed. The black wire is run into the aquastat but the white wire is jumped and connected with a marrette. Another problem is that fact that the infloor heat has no 3-way mixing valve but that issue was identified and is on order. The boiler temps have been reduced slightly until the part is installed.

The issues I need help with are:

Issue#1 - Info on the pressure switch and how to adjust post purge time or a replacement unit that will let me reduce the time to 15-30sec.

Issue#2 - How to properly wire the aquastat or adjust the cut-in low temp to allow a larger diff between start up and shutdown times.

Thanks all for any help. These forums are great.

 
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01-14-18, 10:26 AM   #2 (permalink)  
B,
Pics of the boiler, piping and all controls would be very helpful.

 
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01-17-18, 06:33 PM   #3 (permalink)  
No prob...thanks. Here are a few pics to get started.

 
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01-17-18, 07:18 PM   #4 (permalink)  
Welcome to the forums.

A semi complicated system made more complicated by location.
I don't see any pictures posted. How-to-insert-pictures

That model number you posted for the venter is not a model number.... it's a part number for whatever it's attached to. In the following link are the model numbers. I looked up the relay used and it seems to be a fixed 5 minute time delay relay. I need a picture of that relay/control.
dettson/uploads/2014/09/X40010J_SMH_EN.pdf

other venter relays.... (mostly for my reference)
veris.com/docs/Datasheets/vtd_d01131.pdf
kele/Catalog/Power Monitoring/Data Sheet.pdf


~ Pete ~


Last edited by PJmax; 01-17-18 at 07:35 PM.
 
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01-17-18, 07:39 PM   #5 (permalink)  
Thanks for the info. I'll check it out asap. Still working on the pics. Another fun location issue...internet. haha.

 
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01-17-18, 07:53 PM   #6 (permalink)  
If you have problems posting the pics.... send me a PM and I'll give you my email address. You can send them there and I'll post them for you.


~ Pete ~

 
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01-17-18, 08:21 PM   #7 (permalink)  
Here are a couple overall all pics

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Last edited by PJmax; 01-17-18 at 08:28 PM. Reason: reoriented pictures
 
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01-17-18, 08:24 PM   #8 (permalink)  
Thx pjmax but my problem is with the internet being so slow I am timed out before I can get 1 pic loaded.

In the top pic you can see the 120vAC from the wall going to the high temp & low pressure sensor going down to the burner controller....then around the back of the boiler and up to the proving switch that powers the blower/damper motors.

pump is bottom left of boiler fed by the 4 zone valves...relief valve and main out is behind the boiler going upnto the 4 valves to each zone.....all in red. The clear pex is a recently installed wild loop to stop a bathroom trap freeze up.

there is no 3-way thermo controlled zone valve yet that is on order. Which I understand is adding to the short cycling prob. Hoping if I can get tge aquastat wired properly it may help.

 
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01-17-18, 09:16 PM   #9 (permalink)  
Here is the proving switch that is powering and controlling the power venter. (And yes you are right pjmax. It is locked in 5min purge) therefore I have to replace it as I expected.

The other box is the transformer that is bypassed and going straight to the pump. I am guessing this is the slab sensor power along with a 2 control wires for the zone valves. No longer in use.

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Last edited by PJmax; 01-17-18 at 10:08 PM. Reason: reoriented and labeled picture
 
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01-17-18, 09:37 PM   #10 (permalink)  
Here is the aquastat with the white wire bypassed. Diagram on the cover says it should run through the B and R inputs top and bottom right. But as I mentioned I don't want to mess with it till I'm 100% sure and the replacement arrives.
if I could get this issue fixed and have the low temp in use I think it would stretch out the off time of the cycle an extra 3-5 min.

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Last edited by PJmax; 01-17-18 at 10:31 PM. Reason: add labeled pic
 
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01-17-18, 10:30 PM   #11 (permalink)  
pic 4 - custom timer board. No way to modify.
pic 5 & 6 - that's a 24vac controlled relay. Completely bypassed.

pic 7 & 8 - L6081- 1036 aquastat. Wired for high limit to open just the hot of that circuit. The white is neutral and doesn't need to be opened.

The left side B and R is the high limit switch.
The right side B and R is the low limit switch.

honeywell/TechLit/Documents/L6081.pdf


~ Pete ~

 
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01-18-18, 11:57 AM   #12 (permalink)  
Thanks for that info and confirming that Pete.
Any suggestions for an adjustable timer board that could be retro fit in there or a pressure switch that could replace the whole thing? I'll have to get a pic/specs of the power venter and damper to know that I'm guessing?

As for the aquastat am I safe to assume that if I run the white wire through the B and R on the right side I should have use of the low limit switch/dial and the unit will be firing on that instead of the Diff? I understand that it is fine like that but I'm wondering if that will help with the duration of time the boiler is off and at temp?

I'll leave the 24v relay alone and add an on\off when I remove it assuming the thermostats and zone valves are ok powered from the 24vdc transformer behind the boiler. It's my understanding that 4 zone valves on 1 relay may be too much current if the demand is at the same time...like after a power outage? 3 is preferred but I guess it depends on the amps required by the zone valves and the max output of the relay.

Either way the system doesn't seem very balanced to me and as I said I am worried something will give out soon. Just trying to time the shutdown of the system for repairs with having spare parts around and adding a backup generator and battery in case of a long power outage.

Thanks again Pete you help put some confidence in my thought process on this mess....cheers

 
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01-18-18, 01:47 PM   #13 (permalink)  
I'm responding to so many threads it's hard to keep each one separate.

From the aquastat instructions......
Set the low limit and/or circulator adjustment to obtain temperature desired but not less than 20F (11C) below the high setting. The differential adjustment applies to only the low-limit switch. Minimum differential adjustment provided is 10F (6C) nominal; maximum is 25F (14C) nominal. Set as desired.

Connecting the white wire to the right hand two switch contacts will not hurt anything. I'm not sure if it will do what you want but it won't hurt anything to try it.


~ Pete ~

 
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01-18-18, 07:40 PM   #14 (permalink)  
Understood PJMax, no worries. Appreciate the advice so far.

I've read plenty on the aquastat but I am still hesitant to do anything with it because according to the manual it was never setup properly before it was bypassed. There are so many ways to setup a boiler and it seems here in the north relay switches like RA89A 1119, the one I have bypassed are not used. 99% of the time there is no power vents just chimneys, circ pumps are continously on with a wildloop in place and the aquastats power line runs directly to the blower controller because there is nothing required for vents or timing things like circ pumps.

As it stands I cannot adjust the low limit. seems to have a mind of its own. If I turn the low limit dial there is a click at the correct temp but it doesn't have any affect on the startup temp of the boiler. I'm wondering why everything I read advises not to have a differential between hi/low temps more than 20 but is that for all boilers or condensing units? Or is it due to the added expansion and contraction of the unit and parts? I was hoping to attach the white wire through the aquastat in the hopes it would recognize the low limit. Then I could increase the diff between hi/low to 40F and hopefully add a few minutes to the shutdown portion of the cycle.

I am guessing that I will have to install the 3way valve and exchange the pressure switch for one that has an adjustable purge time before I make any major dents in the cycle times.

cheers and thx

 
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01-18-18, 08:46 PM   #15 (permalink)  
As it stands I cannot adjust the low limit. seems to have a mind of its own.
Are you talking about the low limit on the aquastat in the pictures 7 & 8 ?

That low limit adjustment only affects the right side switch.
I posted this previously....
The left side B and R is the high limit switch.
The right side B and R is the low limit switch.


~ Pete ~

 
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01-19-18, 05:17 PM   #16 (permalink)  
Yes i am referring to the low limit sort of but being able to set it more specially. I understand that it's bypassed now and the right side of the aquastat controls the low limit. Therefore the boiler is only firing off the high limit and the diff...being set at 20 right now.
I'm guessing the blast of cold fluid trips the aquastat every time the zone valves open up and circulates into the boiler.

haha Guess all my babbling is confusing the issues but if you were me how would you....

1) Adjust the aquastat to increase the diff between startup/shutoff temperature from 20 to 40F? Have the aquastat trip at 120-160F, not 140-160F which is current.

2) fix the overall issue of removing unnecessary parts(like the relay) and balancing the heating system? By working with what is there or using the schematic in the manual. I'll add a screen shot below but as you can see it is not what I have setup.

I can add a quick wiring diagram of what I have right now if anyone would like to take a crack at this.




Are you talking about the low limit on the aquastat in the pictures 7 & 8 ?

That low limit adjustment only affects the right side switch.
I posted this previously....
The left side B and R is the high limit switch.
The right side B and R is the low limit switch.

 
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01-19-18, 07:36 PM   #17 (permalink)  
The differential only controls the low limit switch.

Differentials:
High Limit: 10F (6C) nominal. (not adjustable)

High Limit: 130F (55C) to 240F (116C). Stops burner if
boiler temperature exceeds setpoint.
Low Limit: 110F (44C) to 220F (105C). Controls burner during thermostat off periods to maintain boiler water temperature.

I'm thinking that aquastat may not be the controller you need.
Yes.... post a diagram.


~ Pete ~

 
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