hot water boiler heat problem

Dennis12

I have a boiler that ramps up to 200 degrees and I can not get more than 135 degrees on the discharge side of the boiler. The radiant wall heat reflects the same temp. as the discharge, and we are getting about 10 degrees less on the return side of the base board heater. The boiler pump is good and running, all else seems to be working normal, I think we have a part blocked boiler??? The boiler is a slant finn 23 years old.

Timco

You cannot always trust a 20+ year old gauge...does your system have outdoor reset? "blocked boiler" is not a good guess.

Tim

tim smith

I don't know if your boiler has a thermostatic element in it

like Weil Mclain had but with theirs we would see this problem crop up once in awhile on that vintage of their boiler so maybe slant fin has one also

Timco

Ahhhhhh... Laars also uses a thermostatic union and it has a thermostat in it, but when it stuck, the boiler short-cycled for 15 seconds and shut off...over and over. Good call Tim...

Tim

Dennis12

No outdoor reset, and the temp. was measured with infrared at the boiler black iron fitting and was 190 degrees, and temp. on the gauge was very close to that figure. The water temp 20 inches with only a ball valve in line was 135.

Steven Eayrs

???

Actually getting flow? check vlv stuck? Don't see how you can have that big of temp difference if you have decent flow, and not mixing, etc..

How did you determine you had good flow thru the boiler?