Boiler troubleshooting suggestions


  #1  
Old 12-03-16, 06:39 PM
W
Member
Thread Starter
Join Date: Dec 2016
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Boiler troubleshooting suggestions

Gang -

First, thanks a bunch for this forum because it's helped me on a variety of projects along the way.

I have a question that I'm putting up regarding my boiler. I recently bought a home and am getting a crash course on how these things work as I try and troubleshoot an issue.

Here's the problem:
I flick the thermostat to on (while specifying a temp higher than the room), I hear the click from the thermostat, and the boiler doesn't fire up. I have to click the thermostat on and off, sometimes 10 times, before the boiler fires. Once it fires, it will keep going with no issues until it gets to the correct temperature. Then, once the temperature dips and the thermostat tells it to fire back on, more often than now does it not turn back on.

What I've done to troubleshoot it:
1) Replaced the thermocoupler. Still had the same issue.
2) Replaced the vent switch. Same issue.
3) Verified the pilot light was always on during each of these times where it didn't fire - it was.
4) Typical visual inspection looking for random wildlife that might have made a home.... nothing.
5) Verified the vent damper was open - it was.

I then focused on the electrical.
1) Verified the thermostat worked (I have a different one for the AC. Swapped out). Same issue.
2) Replaced battery. Same issue.

And here is where I'm focusing:

The home is from the 1950s and appears to have the original switching relay (the boiler was upgraded).

On the times that the thermostat is on and it should be telling the boiler to fire up, I checked pins 2 and 3 and there is no electricity heading down the line, through a transformer, and to a boiler. However, 2 and 4 have 120v. On the times that the thermostat is off, both 2 and 3 / 2 and 4 have no electricity.

On the 1 in 5 times that I turn the boiler on through the thermostat and the boiler fires up right away, 2 and 3 / 2 and 4 have 120v.

My assumption is that the switching relay has reached the end of its life because it's not correctly sending electricity down the line to the boiler on roughly 80% of the times that the thermostat tells it to turn on.

Any thoughts on this? Am I in left field with this reasoning?

Potentially demonstrating my ignorance, what's the difference between 3 and 4? Is it possible to merely connect the boiler to 1 and 4? Do I need to replace the switching relay?

Attaching a picture of the switching relay. Thanks a million.
 
Attached Images  

Last edited by WindoraBug; 12-03-16 at 06:55 PM.
  #2  
Old 12-03-16, 07:24 PM
C
Member
Join Date: May 2015
Location: USA
Posts: 3,138
Received 2 Votes on 2 Posts
Just to clarify....When you say the boiler doesn't fire up, are you referring to the burner firing up or the circulator pump running?

Depending on a lot of things...it can be perfectly normal for the boiler burner not to fire all the time there is a call for heat. However, the circulator pump will always run when there is a call for heat.
 
  #3  
Old 12-03-16, 07:58 PM
W
Member
Thread Starter
Join Date: Dec 2016
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Thanks for the response.

About 80% of the time, both the boiler and the circulator pump do not turn on when the thermostat tells it to start providing heat. The boiler takes no action whatsoever (presumably, due to the lack of electricity).
 
  #4  
Old 12-04-16, 05:58 AM
C
Member
Join Date: May 2015
Location: USA
Posts: 3,138
Received 2 Votes on 2 Posts
I suspect you are right and the relay is worn out.

I would probably just replace the entire control. They are not very expensive. While it's typical for those controls to have two sets of contacts for controlling two loads the other set of contacts has just as many cycles on them as the set you are using. They haven't been switching a load, so they are probably not as worn as the set in use, but they are still likely quite worn.
 
  #5  
Old 12-04-16, 07:07 AM
V
Member
Join Date: Jan 2010
Location: North East Kingdom of Vermont
Posts: 2,533
Received 1 Vote on 1 Post
As a novice with a failing aquastat, I have been known to physically close the relay myself to see if I could get some action . . . . or shut the power off and file the contacts on the relay to improve the electrical contact (similar to filing the points on an old automobile distributor, if that rings a bell). If closing the relay gets the burner or circulator going, then I'd still go back and remove any corrosion or burnt deposits on the points to clean it up. I think I once had a broken spring on a relay.

Sometimes, that has just bought me a little time to go out and procure a new (or re-built like a Sid Harvey) Aquastat. If the coil surrounding the electromagnet is swollen, it's on its way out; but I've sometimes gotten over a month's additional life out of the Aquastat.

Recognize that this is a response from a fellow DIY Guy; not an HVAC Engineer.
 
  #6  
Old 12-04-16, 07:11 AM
W
Member
Thread Starter
Join Date: Dec 2016
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Replies...

Vermont and Carbide -

Thanks for the suggestions and thoughts. Glad to know that no one (so far) is telling me that my logic is completely off.

One additional question - what's the difference between the 3 and 4 output on the switching relay? I see that there is a difference on the wiring chart but I'm a little lost on what the difference actually means.

Thanks!
 
  #7  
Old 12-04-16, 07:37 AM
V
Member
Join Date: Jan 2010
Location: North East Kingdom of Vermont
Posts: 2,533
Received 1 Vote on 1 Post
Originally Posted by WindoraBug
". . . what's the difference between the 3 and 4 output on the switching relay? . . ."
Don't expect an answer on that one from me . . . . I have only dealt with various Honeywell Aquastats, and even then, never really relied on any numbering system that's probably integral to the circuit of only that specific unit. Yours doesn't look like a Honeywell; but the design components appear identical (or at least similar). I'll look again at your pictures.

Do your contacts appear charred ?
 
  #8  
Old 12-04-16, 08:05 AM
S
Member
Join Date: Oct 2013
Location: United States
Posts: 3,217
Received 81 Votes on 76 Posts
W,
Although I cannot see the model number behind the tstat wire it I believe it's a Honeywell RA832A and if so that #4 terminal is the same as terminal #3 and is for an optional load. You can take the wire from #3 and put it on #4 with no danger. You may have a bad terminal.

Something else you can try is taking the wires off of TT on the relay and jump the TT terminals. It's 24V and no danger. This will eliminate your tstat as the problem. If when jumping the TT the boiler still does not fire the problem is with the relay and not the stat.

As was mentioned the points on that relay get worn or just dirty sometimes and must be cleaned. They used to make a burnishing tool for that purpose but a dollar bill rubbed between the point will do just as well and was used all the time instead of buying the tool as it was easily lost.

At this point I wouldn't worry too much about the points since your not even getting voltage to #3. If the jumping doesn't work go to terminal #4 and that should buy you some time.

Hope this helps.
 
  #9  
Old 12-04-16, 08:38 AM
Z
Member
Join Date: Jan 2008
Location: Southeastern Pennsylvania
Posts: 3,338
Received 38 Votes on 37 Posts
(I type so slow I didn’t read the last 2 posts – I’ll read those after I post this – lol)

I’m no electrical guy to really and truly say the least (lol) but I think this a the proper diagram (not sure)-

My Insteon 2441 thermostat: Install Questions 2441TH

If so I think what you have is hot (power) coming in on 1 and the neutral return for that power on 2.

I think the diagram shows 2 relays which both close when T-T is energized. The 2 relays when closed provide a path for the hot (i.e., a path for 1) through 3 and through 4 at the same time.

So you can hook up 2 devices (or thingies or something, lol, you can see the extent of my electrical vocabulary): one device on 3 and another device on 4.

But a device would need a return path, so the device would have its return path wire (lol) connected back to the return path terminal 2. Looks like your boiler is connected to 3 and 2: i.e., is connected as load 1. So 4 (load 2) is not being used.

I think that’s correct, the other guys I’m sure will correct that if wrong.

It just occurred to me you could use load 2 (2-4) for the boiler but I just read Carbide’s post explaining how they are probably in bad shape also. Probably just time to buy a replacement.
 
  #10  
Old 12-04-16, 10:13 AM
S
Member
Join Date: Oct 2013
Location: United States
Posts: 3,217
Received 81 Votes on 76 Posts
Z,
You are right. #3 & #4 do the same thing, post #8.

On a side note I don't know who you remind me more of, Prof. Irwin Cory or my wife with that terminology. lol. I could use your help with projects if she's busy. You speak the same language and I already understand it.

Thanks for the laugh. Have a Merry Christmas.
 
  #11  
Old 12-04-16, 11:52 AM
W
Member
Thread Starter
Join Date: Dec 2016
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Thanks!

Thanks to all that posted.

Yes, I believe it's a RA832A as well; however, I can't seem to find a model number on it anywhere.

I took a good look at the connections on the mechanical piece that closes to complete the circuit (switch?) and, the #3 spot was badly corroded and had a few little burn marks. I tried to take a picture and it the picture didn't turn out well.

The #4 connections looked just fine.

I jumped the T-T terminals and, when connect to #3, the boiler didn't turn on about once every 4 times (turned the electricity on and off about 10 times).

I then connected to #4 and the boiler fired up every time with no issues.

The culprit was a corroded switch on the relay.

Thanks again to everyone. Posting the resolution in case it helps someone else. Saved me a pricey service call and, for now, the switching relay continues to work.
 
  #12  
Old 12-04-16, 12:34 PM
V
Member
Join Date: Jan 2010
Location: North East Kingdom of Vermont
Posts: 2,533
Received 1 Vote on 1 Post
Originally Posted by WindoraBug
". . . Saved me a pricey service call and, for now, the switching relay continues to work . . ."
Congratulations . . . . that can be a real confidence builder.

Now you'll be looking forward to the next problem !
 
  #13  
Old 12-04-16, 01:43 PM
Z
Member
Join Date: Jan 2008
Location: Southeastern Pennsylvania
Posts: 3,338
Received 38 Votes on 37 Posts
I don't know who you remind me more of, Prof. Irwin Cory or my wife with that terminology. lol.
lol – Hardly ever hear that name anymore. He used to crack me up. No kidding, this is the truth -I have actually thought of his name in recent times listening to some of these weasel politicians.

Have a Merry Christmas also!

And …Glad you got it licked WindoraBug!
 
  #14  
Old 12-04-16, 02:39 PM
W
Member
Thread Starter
Join Date: Dec 2016
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Finally snagged a good picture of the connectors. You can see the #3 connectors within the RA89A is a bit ugly where #4 looks just fine.

Posting in case this helps someone else in the future.

Name:  IMG_1051.jpg
Views: 413
Size:  39.4 KB
 
  #15  
Old 12-04-16, 06:20 PM
D
Member
Join Date: Apr 2014
Location: us
Posts: 1,120
Received 54 Votes on 52 Posts
There are several trouble shooting points.

Some thermostats, especially those used for both heating and cooling have a built in delay of 3 minutes or more from turn-on/power on. Check to see if yours has a delay.

The old controls with open, uncased relays were prone to developing dirty contacts and had to be cleaned with a file occasionally. Often they would mechanically close but not make good electrical contact. I have a 120VAC pilot light that shows when it is calling for heat.

You have not mentioned what type of primary oil burner control is activated by the aquastat. It is the last link in starting a burner.

Make you life easier and spend $65 for Honeywell R7284U primary universal controller with digital display that hows status and history. When aquastat is not calling for heat it displays "Standby", and has many other status messages.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: