Slantfin Hydronic Boilers

Steve Toland

promblem - Slantfin Hydronic Boiler, L-30 3 section cast iron. has 2 autovents on the 2 3quarter inch tappings on the top and no venting on the supply manifold. has triple aquastat wired for priority on the main zone. and 2nd zone separate relay. boiler feed is on the bottom/back of boiler.
Burner - Riello F5 nozzle size - .65 60 hollow. demestic hot water, 5 gallon coil with watts 70A mixing valve.
aquastat is new. burner is new. wireing is new. piping is new. boiler is about 10 yrs old...
QUESTION - Boiler overrides, goes into steam and percolates??????????????????????????????????????

Paul Mitchell

Could be the

well for the aquastat. Maybe it is corroded and not letting heat through to bulb or the aquastat is bad...or maybe the gauge is bad. Just a few ideas.

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Mark Wolff

High Temp

Drain the boiler some and remove the immersion well for the triple aquastat. Clean the well of any corrosion, and reinstall. Put some fresh heat transfer grease in the hole and insert the aquastat probe. If this doesn't do it, try turning down the high and low limits proportionally. Sometimes they aren't exactly accurate from the factory(you said it was just replaced) and if you are running your boiler on the hot side 200* plus, you could very easily end up with an overheating situation. Try turning the hi down to 180* and the low to 160* and see if that alleviates the problem. Another possiblility is that your new triple aquastat relay is not functioning correctly, and may need to be replaced.

The other REALLY important possibility is that when "whoever" replaced the wiring, burner, triple aquastat, etc. they didn't hook it back up right; which brings us to the question...

If the boiler was only 10 years old, why was the burner, triple aquastat, wiring, etc. replaced? Boiler fire?

Unknown

It sounds like it might have sedement in it

Try the well, first.

You can call Slant/Fin Tech Service at 800 873 4346, if we can help.

Noel

Steve Toland

Pushing Water???

Abviously the popular way of piping boilers these days, is by pushing water rather than pulling water. question - Can air problems in the heating pipes be eliminated by piping the circs. on the supply ? or is that a touchy subject for some of you techs. out there...

Jack, CVMS

Pulling Water????

Steve,

Most, if not all, problems with air in a properly designed system can be eliminated by putting the circulator pump on the supply side. You should order Dan's book "Pumping Away" for a definitive treatment of the subject.

A pump cannot "pull" water. While a pump can generate positive pressure on the discharge side, all it can do on the suction side is to remove pressure and allow atmospheric pressure to push a fluid into it. The maximum suction pressure any pump can achieve is atmospheric - approximately 15 psi or 30" hg (1 bar to our metricized friends)