Boiler Overheating

mstarbird

This boiler is been having issues off and on for months. 6 months ago the watts pressure regulator with backflow preventer was replaced and the expansion tank and valve above it was also replaced. Now the boiler is pegging out at 240 again every time it turns on. The Honeywell is set at 210 on the high end trying to prevent it from getting to hot. Worked for a few hrs but it's again up to 240. The pressure is at 25 which is also up. I checked the screen on the watts and it's clean. Could the new pressure regulator be bad already?

mstarbird

Also the boiler is a Biasi b series with a Riello 40 burner. System is 14 years old.

Ironman

More info needed. How about some pics? What make and model boiler.

But no, the fill valve will not cause the temperature to go too high; your aquastat is not functioning correctly. There may be other issue too.

Gilmorrie

This is a hot-water boiler? In my opinion 210 deg F is too high for the aquastat. Try 170 deg.

mstarbird

Boiler info was posted above. Temp also continue to climb 30 degrees after boiler kicks off. Aquastat was turned down to 210 after the pictures of the face plate was taken.

EBEBRATT-Ed

Set you high limit aquastat at 190 deg. The water pressure will change with the water temperature...this is normal about 12-15 psi when cold 25 is ok when hot with a properly functioning feeder and expansion tank it should not go much over 25 as your relief valve may open.

One question: The city water should feed through the backflow preventer first and then through the water feeder to get to the boiler....check that

Also with the aquastat set at 190 it should shut the burner off at approximately that temperature. If you pumps shut down with the burner you temperature may rise above the 190 set point by 5-10 degrees due to residual heat trapped in the boiler. this is normal

mstarbird

One of the reasons I was leaning towards the watts pressure regulator was I drained off a bunch of the pressure and when I lift on the blade it's not feeding or seeming to not be feeding the way it should be. Pressure isn't changing and no noise is being made.

mstarbird

The water system is off a well. It's not city water. One of the reasons we checked the screen on the watts. But it was clean as a whistle.

Ironman

All of those circulators need to be rotated so the motors are horizontal. They'll fail they way they now are because the bearings won't be properly lubricated.

mstarbird

The loop on the heat and hot water at 15 psi gives really low water pressure at the far end of the house. It was upped to 20 psi this summer and worked great. The 25psi started today.

mstarbird

To answer Ebebratt-Ed's question, yes it enters the back flow 1st then the watts then the boiler. Just doesn't sound like the water is making it through the regulator.

Intplm.

I must ask...............Is the water on? Did you remember to open (all) the manual valves supplying water to the boiler?
I ask because it looks like from the pictures that you also have a new manifold and circulators installed. Quite a bit of work.
Hey ! Sometimes folks forget !?

And re-read what Ironman said about the circulators. They are installed to prematurely fail.

mstarbird

Nope the manafold and the Taco's are all 14 years old. The water was on. I turned it off when I inspected the watts but in the picture you can see the water valve in front of the back flow is on. The one after the regulator is on as far as it can be turned on. The Master plumber that installed the system used a manafold that too short and the Taco's can not be turned horizontally. There isn't enough room between the zones. This plumber has cause a lot of problems.

Jamie Hall

Any water feeder problems you have and the temperature problem are not related at all. The temperature problem may be a bad aquastat -- if you set it to 190 and the temperature still soars, that's where I'd look first.

neilc

@intplm
@Ironman
on the circs,
I understand why the motor doesn't want to be vertically "up", it traps air,
but what would be wrong as the picture is?

Ironman

neilc said:

@intplm
@Ironman
on the circs,
I understand why the motor doesn't want to be vertically "up", it traps air,
but what would be wrong as the picture is?

Debris settle to the bottom effecting the bearing.

neilc

got it
ty

Intplm.

Jamie Hall is on it. Cant tell what kind of aqua stat you have from the pictures...blurry...If the aqua stat was removed during repairs and then re-installed or hit , the temp sensing bulb or line that attaches the bulb might be damaged and therefor not reading correctly.
Cant tell from the pics if its the type I'm describing.
Still sounds like the aqua stat.

mstarbird

The aquastat is a Honeywell 4006a. Aquastat was not replaced last summer. Only the tank and the regulator and the relief valve. The Aquastat has never come out of the boiler at least not since the day it was installed. The original plumber had it set to 240. It was turned down to 220 then to 210. It's now down to 180. The temp seems to be not crossing 190 today. But the wood stove is running since temps are on the negatives. The boiler hasn't had to turn on as much today.

Intplm.

You may have solved the problem then. But set it down to 190 and continue to monitor your results..

mstarbird

I hope so thanks everyone for the help!!!!

GBart

yeah, your high limit should never be set above 200F, ever, maybe your plumber needs glasses