McLain Weil No 57 Oil burner.
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McLain Weil No 57 Oil burner.
Hello All, My oil burner pressure guage goes past the safe 30 and into the red unsafe zone and does not stop unless I use the emergency cut off switch. I do not have an expansion tank any where in the house. It is an old house. Also the thermostat does not shut the furnace off . So what i do is use the emergency switch to run the furnace for about 20 mins twice a day which heats up the radiators(not much but you can feel heat) then shut it off. Is this safe to do? and how can I solve this issue without calling the oil repair man. Thanks in advance for any advice.
#2
Take more pics......
Welcome. I see a fill valve so its not steam...LOL.....
You have an expansion tank... Its probably in the ceiling above the boiler. Pics.
1. You may need to drain that tank..
2. You may have a faulty gauge.
Or possibly.
3.Bad fill valve
4. Over temperature and bad aquastat...........
Last.
If no water out the relief valve during this high psi reading then the relief valve may be bad too.... Bad things can happen so beware!!!!!!!!
Welcome. I see a fill valve so its not steam...LOL.....
You have an expansion tank... Its probably in the ceiling above the boiler. Pics.
1. You may need to drain that tank..
2. You may have a faulty gauge.
Or possibly.
3.Bad fill valve
4. Over temperature and bad aquastat...........
Last.

#3
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I just cannot find an expansion tank anywhere, not in attic or basement. There is only about 8 in clearance above boiler. Is it possible that this can be rigged to work without expansion tank?
When I see the pressure rising to the red area in guage I let some water out from the lower pipe and the guage drops and I let run a little longer before turning off emergency switch.
Thanks for the reply.
When I see the pressure rising to the red area in guage I let some water out from the lower pipe and the guage drops and I let run a little longer before turning off emergency switch.
Thanks for the reply.
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This is an old system in an old house. It is possible the expansion tank is in the attic.
Step back a bit with additional pictures so we can see how different parts fit together. More pictures are better than fewer but please, only well-lit and in focus pictures. Fuzzy dark shadows don't help a bit.
Step back a bit with additional pictures so we can see how different parts fit together. More pictures are better than fewer but please, only well-lit and in focus pictures. Fuzzy dark shadows don't help a bit.
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I have searched the attic there is none. I just cannot find an expansion tank anywhere. There must be some other way this thing is working without exp tank. I have taken some more photos and put theme here.
FurnaceImages
Thanks again.
FurnaceImages
Thanks again.