Replacing 1957 American Standard boiler

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  #1  
Old 01-09-19, 05:59 AM
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Replacing 1957 American Standard boiler

Time to retire the original oil hydronic boiler. Currently have an American Standard tankless that has been on its last legs for the last few years. Having all kinds of intermittent issues and local techs (and common sense) point to replacing rather than throwing more $$ at it.

My goals are to replace with another oil hydronic system and my main priority is reliability and ease of service. Not sold on electronic do-dads so I want something simple.

Local heating contractors use Weil Mclain, Burnham, Buderus, and Viessmann so it will be one of those.

Small (1000sq ft) ranch home and well insulated. Again, my priority is simple maintenance and reliability, squeezing every single BTU out of it isn't all that high on the list. Cost is also a factor but will to pay for the right equipment that meet my needs.

Suggestions as to which brand or all they all pretty similar?

Thank you in advance.

 

Last edited by Rob in Maine; 01-09-19 at 06:01 AM. Reason: ad picture
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  #2  
Old 01-09-19, 10:54 AM
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You mentioned you have a tankless coil. If you intend to continue with a tankless coil with the new boiler Buderus and Viessmann are not available with tankless coils and must either use an Indirect or separate fired hot water heater.

Buderus and Viessman are triple pass boilers for better efficiency although you said that doesn't matter, Weil McLain and Burnham both are single pass boilers and come with or without tankless coils.

If efficiency is not an issue they are all good boilers. Burnham had some casting problems but as far as I know they have been corrected.

Different brands are prevalent in different parts of the country and even different areas. My only suggestion is to make sure parts are readily available locally if problems arise. Putting in a packaged boiler is one thing, servicing it is another.

Most boilers come with a choice of burners. Again, make sure parts are readily available in case of service.

Hope this helps a little.
 
  #3  
Old 01-09-19, 06:18 PM
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How much HW demand in the household? Since you plan on replacing the boiler, this is also a good time to determine the type of HW maker that will best suit your needs.
 
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Old 01-10-19, 04:35 AM
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Thank you for the comments.

The DHW demands are pretty low. The home only has one bath and the current system w/DHW coil has met the demand without issue.

For cost savings I will probably stick with a similar systems unless an indirect can be added economically. I have a contractor coming over in about 10 days to take a look and give me an estimate. Any specific questions (other than how much and when can you do it) I should be asking?

Thanks again for your help.
 
  #5  
Old 01-10-19, 06:40 AM
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Indirects are not cheap but payback via oil cost savings can be pretty quick (sometimes in just a few years) depending on how much oil you use in the off season.

As far as specific questions: Spott's advice is dead on.
 
  #6  
Old 01-11-19, 06:13 AM
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Ok, so the boiler is on its last legs and I have a contractor coming out in a week to price out a new one.

But in the meanwhile...

The intermittent problem is becoming more of an issue. The boiler will only light if I hit the red reset button located on the Aquastat.

Once I do that the boiler will heat up to the high limit and shut off. Every single time.

When the temp drops the boiler will not relight (this is the intermittent issue).
A call for heat or DHW will not relight the boiler (again, an intermittent issue).

The Aquastat was replaced about two months ago (high limit is 200 and low limit is 160 w/diff of around 15 )

The electric eye thing that sees a flame was also replaced.

New filter and fresh heating oil

Will be -5 tonight and -7 tomorrow. I can also heat with a wood stove so that isn't as big as an issue as it might seem, but I would like to have an idea what is going on.

Basically, it seems like the boiler, the pumps, etc are working exactly as they should, but only if I hit the red reset.

Thank you in advance.
 
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Old 01-11-19, 07:59 AM
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What is the make and model no. of the aquastat? Is it a strap-on type or does it have a bulb that goes into a thermowell? A photo of the 'stat would help - I don't see it in your photo.
 
  #8  
Old 01-11-19, 08:53 AM
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Honeywell R8182D.
It is that gray box w/red button in the picture. If I tap that button once the boiler will always fire 100 percent of the time an run up to the high limit and shut off.

Usually it will work for a few weeks but last couple of days it is getting more and more flakey.
 
  #9  
Old 01-11-19, 11:51 AM
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Here is data sheet for your 'stat: https://s3.amazonaws.com/s3.supplyho..._PROD_FILE.pdf

What seems to be happening is that when there is a call for heat, a timer starts. If flame is detected within the timer's setting, the safety switch is bypassed. If flame is not detected, the safety switch trips, and you have to manually reset it. Something obviously is wrong. Call back the guy who installed the 'stat.
 
  #10  
Old 01-11-19, 12:42 PM
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Thank you taking the time to reply.

If I understand correctly when there is a call for heat of DHW the safety timer has to see a flame from the cad cell within 45 seconds and if it doesn't, it will prevent the burner from dumping fuel into the chamber.

To test the safety switch: If I have someone turn up the thermostat and call for heat while I'm in the basement should I hear the pump or something else running for those 45 seconds?

If I don't hear anything but silence, does that suggest that the safety switch isn't the issue?

I hope these questions makes sense.

Thanks to all that have provided me some help. It is appreciated.
 
  #11  
Old 01-11-19, 01:12 PM
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Rob,
There are basically 2 reasons for a boiler to shut down on safety. No oil or no ignition. You know you have oil, so in the oil family is the pump and the nozzle. If it was the pump it would not be an intermittent problem. If a pump is clogged or defective it just stops working and the nozzle the same thing so you can eliminate oil.

The other thing is ignition. This takes in your transformer and your igniters and possibly in your case ignition cables. Not sure if you have cables, some did back then.

With your intermittent problem my suspicion is your transformer. Those old style transformers, instead of just dying they became weaker and over time worked intermittently before they just finally went dead. They may work for a week or a day and then one time not produce enough spark for ignition, then when reset may work again for an indefinite period of time and then not produce again.

Your ignitors could be a possibility by having hairline cracks in the porcelain or worn electrodes but the problem would be more constant.

Your aquastat is not the problem, it is just doing its job by shutting down the boiler if there is no flame, most likely in 45 seconds by means of the cad cell so you do not empty the tank of oil with no fire. Your cad cell is doing its job by shutting off the burner if it doesn't see light which represents the flame in that 45 seconds. It's the safety to make sure the burner does not keep pumping raw oil into the chamber and possibly beyond when there is no fire.

There is a tester to check your transformer but sometimes even if it shows good the bakelite inside these old transformers breaks down causing intermittent problems.

What I would look at is your transformer before I changed any more parts.

Hope this helps a little.
 
  #12  
Old 01-11-19, 01:22 PM
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This explains the operation:

OPERATION R8182D A call for heat by the thermostat pulls in relay 1K, which energizes the safety switch circuit and relay 2K to turn on the burner. Safety switch starts to heat. If burner ignites within safety switch timing, the cadmium sulfide flame detector sees flame and the safety switch heater circuit is bypassed. The burner operates until the call for heat is satisfied. The circulator operates when relay 1K pulls in only if R to W is made in the Aquastat¤ limit.
When R to B (low limit) is made by a drop in water temperature, it acts as a call for heat, pulling in relay 2K to turn on the burner. The circulator cannot operate. See Fig. 11, 16, 17 and 19.

Figure 11 shows the schematic of the 'stat. If you can read a relay diagram and have a voltmeter that you can use safely, you should be able to see what is happening or not happening when there is a call for heat - for example whether relays 1K and 2K are pulled in.

Since your 'stat was just installed two months ago, why not just call the installer back?
 
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