Boiler Pressure TOO HIGH, MG-75-n-ps


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Old 09-21-05, 02:04 AM
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Boiler Pressure TOO HIGH, MG-75-n-ps

My system pressure is so high, when the boiler turns on it went over 30psi.
This boiler is about 6-7 years old(bought the house brand new 6 years ago so...)

I had it tuneup last season bcuz not getting heat at some room. The system was just dirty so the technician just flush the system, he also replace the pressure relief valve. A month later, the circulator pump die and the boiler was banging like crazy. So i replace it myself with a Bell&Gosset pump. I'm not sure if i bleep the system properly but i notice that when cold or first turn on, it start off at 15psi and once it heated up the gauge went way pass 30psi. I try shutoff mainwater supply but same thing once its heated up it just go pass 30psi. This started...i noticed it a month later after i install the pump, i forgot about this problem until today its startin to get chilli again =)

Also what the right way to set the regulator? Its range is 10-25, i losen it 1.5 turn and lift it up, dont know if this is right?

I dont much about these thing but if somebody could point the part thats defective i can replace alright. Maybe someone here could help me?
 

Last edited by h04n9; 09-21-05 at 12:10 PM.
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Old 09-21-05, 02:05 AM
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i've some pictures of the system if this is any help...

http://www3.telus.net/nnguyen1/
 
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Old 09-21-05, 05:58 PM
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Pressure too high

What a mess. Glad I don't have to work on it. Anyway, it sounds like the red tank might be bad. You would have to take it off to test it. May as well replace.
 
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Old 09-21-05, 09:21 PM
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There's so little clearance under the red tank, i wonder how they put it there in the first place. Its gonna be tough to take this thing out.

Grady so i have to drain the whole system to take the red tank out, by the way is this call the expansion tank? And how do i test this thing, to know if its working properly or not?
 
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Old 09-22-05, 06:25 PM
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Checking/replacing tank

I don't mean to sound like I'm giving you a short answer but your best bet is to get a pro in there to re-pipe that boiler. I've see a lot of piping disasters but yours takes the cake. I know money does not grow on trees but sometimes you just need to call in an expert.
If I had to replace that tank, I would cut it out, pipe up a small manifold & use two #15 tanks in place of the #30 you have now. This is something I would only do in an emergency. No service person with any respect for their work would do any less. Many would just plain refuse to work on it without major re-piping.
I is commonly called an expansion tank but more properly called a diaphragm tank. These tanks are also often refered to as Extrol tanks even though Extrol is a brand name.
 
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Old 09-22-05, 07:26 PM
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yah, i gues i'll just get a pro to do this.

Grady, what was the reason that you suggested to re-pipe this system. Is it really bad, how they do it? I wonder how much this is gonna be, the tank and possibly re-piping? Last time just a tuneup, flushing and replace the relief valve they charge me $375.

Also whats that thing on top of the tank, is that called automatic air vent? Whats the purpose of it, whats the cause if its bad? Bcuz before, this thing was dripping out quite a bit when boiler was running.
 
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Old 09-22-05, 07:56 PM
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Re-piping

The reason for re-piping is to gain access to parts which may at some time need to be repaired/replaced. With the current piping arrangement, one cannot even get the vent (exhaust) pipe off for cleaning, inspection, or replacement. I'm fairly sure the top panel of the boiler needs to be removed to inspect or clean the flue passages. Even though gas fired boilers don't need as much maintenance as do oil fired boilers, those flueways need to be inspected once in a while.
They will have to cut out a lot of the existing near boiler piping & redo it almost from scratch.
I could not begin to give you an idea as to cost due to wide variations in labor cost from area to area & contractor to contractor. I suggest you call a couple of plumbers &/or HVAC contractors & have them come out to give you estimates.
The black cast iron thing on top of the tank is an air scoop to help get any air up to the small brass automatic air vent.
Air vents go bad for a lot of reasons & are usually cheap & easy to replace.
 
 

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