Questions and Concerns on my 1981 Peerless Boiler


  #1  
Old 10-12-11, 10:56 AM
B
Member
Thread Starter
Join Date: Oct 2011
Location: USA
Posts: 4
Upvotes: 0
Received 0 Upvotes on 0 Posts
Questions and Concerns on my 1981 Peerless Boiler

Just bought a house with this guy inside. Never really paid much attention to it until my brother in law came over and started pointing out issues. This past weekend we replaced the expansion tank and PRV which was corroded inside and would leak.

My questions and concerns are the following:
Last night i looked at the temp/ psi gauge while the heat was running. Normally it's a steady 15 psi/ 180 degrees. Last night it was 20 psi @ 200 degrees.

This morning while my wife was taking a shower, i turned the heat on and went back downstairs to check the gauge. 22 psi @ 202 degrees.

Is this common? the PRV hasnt blown anything off yet and my automatic bleeder on the air scoop seem to be releasing air for a 20 second time frame when i first turn the heat on. I've gone around the house and and opened up all the register bleeder valves and only one pissed air for about 1 minute, water came out, and i closed.
No other registers in the house seem to release any air nor water but they they are somewhat old and corroded. I took a shower and when i checked the gauge, it was back at its normal 15 psi/ 160 temp, but I turned the heat off. Could it be possible that remaining air in the heating lines is causing a spike in pressure when it's heated and expands? If the high temp on the furnace is set to 180 and i have temps reaching 202 degrees, is this common?

Any help is appreciated!
 
  #2  
Old 10-12-11, 11:07 AM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 15,993
Received 85 Upvotes on 77 Posts
If the high temp on the furnace is set to 180 and i have temps reaching 202 degrees, is this common?
No. If the aguastat is set at 180F the burner should shut off at that temp. If may rise slightly but not to the 200F + mark.

What is the make and model aquastat?

How do you heat the hot water?

What expansion tank did you purchase? I have seen potable water tanks installed by mistake before.

What heat emitters? Radiators? If so you really need to get the bleeders fixed/changed.

I guess start there. Others will chime in most likely.

Pics tell 1000 words, so post some at all angles, near and far.

Post to a free site like photobucket then post the link back here.

Mike NJ
 
  #3  
Old 10-12-11, 12:39 PM
B
Member
Thread Starter
Join Date: Oct 2011
Location: USA
Posts: 4
Upvotes: 0
Received 0 Upvotes on 0 Posts
Hot water runs through boiler as well. It seems to only spike in pressure and temp when the circulators are running -my house is 2 zone. I'm at work right now so this is the infor off the top of my head.

-Honeywell aguastat
-Watts 4.5 gallon #30 expansion tank
-Heat Emmiters are baseboard hot water aluminum fins
-It looks like the elbow fittings are tapped so soldering new elbows with bleeders will not be needed. only fitting replacement.
 
  #4  
Old 10-12-11, 02:40 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 15,993
Received 85 Upvotes on 77 Posts
Are you getting heat to all zones?

What are your settings in the aquastat?

Possibly airbound? How did you purge the system after you changed the tank and feed valve?


Mike NJ
 
  #5  
Old 10-12-11, 03:03 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 19,710
Upvotes: 0
Received 8 Upvotes on 6 Posts
This really should have been posted in the boiler forum... but whatever...

It is totally not uncommon for boiler gauges to lie.

Before chasing boiler ghosts all over the place, the first thing to do is verify that the gauge is accurate, both the pressure and the temperature sides.

Since you have a 30 PSI relief valve on the boiler, the pressure could safely be as high as 27 PSI. It's not common that there will be that much expansion pressure increase though.

Typically, a COLD boiler at 12 PSI might increase to say 20 PSI when it is heated to 180.

Was the pre-charge on the expansion tank checked before it was installed? This pre-charge should be equal to the cold system pressure of 12 PSI. Incorrect pre-charge of the expansion tank can cause unusual pressure excursions.

Any extra air in the system piping will NOT cause any unusual pressure increases, in fact, it will cause just the opposite. Any air in the system will act as 'extra' expansion capacity, since air can be compressed, while water can not.

Tell us what the settings are on the aquastat --- the LOW, DIFF, and HIGH dial readings.
 
  #6  
Old 10-12-11, 03:42 PM
B
Member
Thread Starter
Join Date: Oct 2011
Location: USA
Posts: 4
Upvotes: 0
Received 0 Upvotes on 0 Posts
140 low 180 high 10 diff

and yes i am getting heat to all zones.
The boiler climbs to about 200 degrees/ 21/22 psi and then shuts itself off while the circulator runs

i also made sure i got the right type expansion tank. the precharge was 12psi. its an EXT # 30
 
  #7  
Old 10-12-11, 03:52 PM
B
Member
Thread Starter
Join Date: Oct 2011
Location: USA
Posts: 4
Upvotes: 0
Received 0 Upvotes on 0 Posts
i opened all the ball valves and purged each zone for about 5 minutes, occasionally kinking the hose to build pressure again. turned on the heat, went to each register and opened the bleeder valve.

Its awkward how the registers worked... when i first turned on the heat and let it run for 5 minutes: both in the kitchen worked, 1 of the 2 in the dining room worked, nothing in bed 1, nothing in bed 2, but master bed and master bath worked fine.

I went around to all rooms and opened the bleeders individually and the only one that pissed air was bed 2 at the 1 1/4" supply line to 3/4" tee split. It pissed air for about a minute straight, i got water, and then all remaining registers worked fine.

all these are on the same zone too. MY living room is 610 sq ft and is considered it's own zone (addition to the house)
 
  #8  
Old 10-12-11, 06:50 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 19,710
Upvotes: 0
Received 8 Upvotes on 6 Posts
A higher diff would not be inappropriate. 15 or even 20... the 140 and 180 are fine.

Like I said, before you start worrying about anything, you need to verify the gauge accuracy.

It's not at all unusual for the gauge and the aquastat to disagree, either or BOTH could be 'off'. The important thing with the aquastat is that the shutoff is REPEATABLE, that it does the same thing every time. If it doesn't, then replace it. Not until you are sure the gauge is accurate. I can't tell you how often boiler gauges are bad... because I don't have enough fingers and toes... seriously, they are NOTORIOUSLY bad. To the point of ppl spending LOTS of money on 'fixes', only to find that a $20 gauge was the only problem.

Another thing... the gauge and the aquastat are often some distance from each other in the water jacket around the boiler. Inside the boiler the water can differ in temperature pretty drastically from one point to another.

As an experiment, turn the aquastat HIGH down to 170 and watch the boiler for a few days... see if the temp gauge reflects a 10 degree difference.

Are you actually into the heating season at this time? When the boiler is only running for domestic hot water use, the water shouldn't get much hotter than the LOW setting dial. The HIGH setting ONLY comes into play when there is a heat call from a thermostat.
 
 

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