Oil Furnace Water Temp Going to 200

Benduchi · Post by **Benduchi** » Sun. Jul. 10, 2011 5:41 pm

Hello Last night I found alot of water in the basement and saw a pipe leaking from the back pressure prevention valve so right before the valve is a shut off and after the back pressure valve a check valve so I shut of the valve before it and the leak stopped so I went about sucking up the water later on I looked and saw the blue Psi on the gauge was at zero so I turned the valve back on and opened check valve to add water to the system in thoughts of raising blue psi amount it didnt go up so I shut it off again and the valve too well the boiler came on and temp went up to 196 so I shut off red boiler switch however psi is steady 10 so I waited for it too cool and turned it back on temp goes all the way to 200 so I shut it off again checked setting low is 140 high is 160 diff is at 10 so what is wrong with my system ? because of this I am leaving the boiler off and so we have no hot water. I am not a tech I am mechanically inclined and hope to fix this myself with you're help

Boiler is oil fired instant on hot water and heater system
Wein Mclain p-468-wt I would appreciate any help I can get Im including pics to speed up the process

AA130FIREMAN · Post by **AA130FIREMAN** » Sun. Jul. 10, 2011 9:36 pm

Why is the pressure reducing valve off on top of the boiler (you need one installed !!!) ? Electricial wire stripping pliars used for ? Could you have air in the system (leak)that is not allowing the temperature to reach the aquastat ? Is their a low water cutoff installed ? Do not pull the red temperature set knobs off the aquastat or the true setpoint will be lost by the indicator. Alot of guessing here over the internet

Benduchi · Post by **Benduchi** » Mon. Jul. 11, 2011 1:42 am

Are you refering to the 5th picture? I believe it was replaced can you look at the first pic and tell me if its missing

*Blue pliers were to cut the twine I used to hold a hose over the pressure preventer valve (pipe) and ran it to a bucket

Post by **Rob R.** » Mon. Jul. 11, 2011 2:30 am

Faulty backflow prevention valve, faulty aquastat, faulty gauge, low water level in the boiler...there are a lot of different things that could be contributing to this. I suggest that you get a qualified tech. to look at this, a leak is one thing but uncontrolled boiler temperature is another. If things aren't seating properly in that backflow prevention valve you will get discharge from the drain pipe. Perhaps it needs to be flushed out, or replaced.

AA130FIREMAN · Post by **AA130FIREMAN** » Mon. Jul. 11, 2011 9:06 am

markviii wrote:Faulty backflow prevention valve, faulty aquastat, faulty gauge, low water level in the boiler...there are a lot of different things that could be contributing to this.

All the above and a faulty expansion tank. It does look like in the first picture the pressure relief valve is installed. DO NOT cap any of the vents. Did you do anything before this problem occured ? Seing tools and parts on the boiler makes me think some work was being done.

Benduchi · Post by **Benduchi** » Mon. Jul. 11, 2011 10:52 am

The work was old parts stayed there almost a year old on last work done

Everything was running smoothly until the other night as posted thanks for the info I have someone coming ill post his findings and repairs

Post by **franco b** » Mon. Jul. 11, 2011 4:42 pm

What I would do. The back flow preventer is to prevent boiler water from entering your domestic water supply in the event the domestic supply loses pressure. They go bad. I would put a plug in it or replace it. The boiler pressure is not too high so the expansion tank is OK. What you call a check valve is the auto boiler feed which is working since the boiler pressure is alright. If it bothers you to have a plug in the backflow valve then you can close the manual feed valve and only open it if you hear gurgling in the pipes indicating low water pressure in the boiler. Get the pressure up and close it again. You only need enough pressure to raise the water to the highest point. I have only heard of a low water cut off on steam boilers.

I would set the high point on the aquastat at 180 and the low at 160 with 25 degrees differential. With the boiler running lower the low setting to see if it will turn off the burner. It is possible that the burner is being controlled by the high limit and the low limit is always on. Maybe incorrectly wired.

Tap the gauge to see if the hands are sticky.

It's a strange looking installation with lots of pipes I have no idea what for, could probably get rid of a few.

That looks like a monster smoke pipe for that little boiler; is there a baro installed?

AA130FIREMAN · Post by **AA130FIREMAN** » Tue. Jul. 12, 2011 12:35 am

What brings an oil burner guy to a coal websight for advice ? Seems their would be a web for oil burner guys to talk about sauda arabia oil is far superior to alaskia

I'm just fooling with ya on this one

We'll help who we can (if we can)

Freddy · Post by **Freddy** » Tue. Jul. 12, 2011 7:02 am

I'm glad you're getting a professional in to look at it. If it is low water, it's a perfect expamle why every boiler should have a low water cut off as is mandated in my state. If it is not low water, and correct me if I'm wrong, but I think it means that two controls have failed at the same time, or, the high limit failed some time ago & you didn't know it, and now the aquastat has failed also. At least the high pressure relief worked as planned! This is the type of thing that Harry Homeowner sees the relief dripping, solders a cap on it, and then.....then.... KA-BLOOMIE!! In one split second NASA has competition. Oh, wait, I forgot, NASA doesn't shoot off rockets.

steamup · Post by **steamup** » Tue. Jul. 12, 2011 9:20 am

It appears something in the feed water system has failed. If the PRV settings were left at the factory setpoint, the pressure in the system when cold should be 12 psi.

Low water pressure from the leak may have let air in the system when the system cooled off. If there is air at the Aquastat sensing location , it will slow the response and allow the boiler to overheat.

Since you are not mechanically inclined, I would leave the repairs to a experienced person, so a complete safety check of the system can be accomplished. More than one thing could be bad in the system.

Benduchi · Post by **Benduchi** » Tue. Jul. 12, 2011 9:43 pm

Thanks for the many replies I too now think the whole thing is just the back pressure being faulty I have a tech coming on Saturday as he felt it wasn't serious enough to come out right away which is fine for me I don't want to pay an arm and a leg LOL

As far as water pressure that's fine and hasn't changed at all during this problem we use well water so I understand why there a back pressure preventer valve I wont remove it but I have talked to my tech guy and his plan is to replace that valve on Saturday I hope that's all that's wrong and I also hope he can help me label the 20 valves that are there LOL and yes it is a strange setup thanks again and Ill post the info on Saturday

AA130FIREMAN · Post by **AA130FIREMAN** » Wed. Jul. 13, 2011 1:21 am

With the triple aquastat set at 140 low and the differential at 10, the burner should come on at 130 and stop at 140. The high limit should not come into play this time of year (I assume you are not heating the house or have an indirect water heater) just running hot water threw a domestic coil the boiler should only try to maintain the low limit. Why the gauge in the picture was at 190 ????? When their is a call for heat in the house that is when the burner should fire to the high limit. ANY THOUGHT OF REPLACING WITH A COAL STOKER

AA130FIREMAN · Post by **AA130FIREMAN** » Wed. Jul. 13, 2011 1:29 am

Also, if the water was coming from the back flow preventer, could it be you lost pressure in the house water system ? Problem with well pump or borough flushing hydrants. The idea of the back flow proventer is to stop nasty boiler water from contaminating the drinking water, if line pressure was less than 15psi that could happen without it.

Benduchi · Post by **Benduchi** » Thu. Jul. 14, 2011 5:05 pm

Can anyone tell me how to add water just based on pics posted or would you need more cause the boiler hit 220 and I had to shut it down again and my 5 gallon pail was full of water so I too believe that it needs water and would like to try and add some just until tech guy can come replace the bad valve and inspect the rest

Benduchi · Post by **Benduchi** » Thu. Jul. 14, 2011 6:04 pm

OK I made a small walk around video of the boiler and can and will gladly provide more if needed thanks again for all your help

Oil Furnace Water Temp Going to 200

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