Symptoms of a leaking indirect ?

Unknown

that was connected to a Phase 3 HL60 ( domestic HW ) and a sidearm coil for a pool heater . No heat zones . After purging we noticed the boiler pressure slowly rising , so we shut the ball valve for the PRV . It still slowly crept up while we lowered the pressure through a hose at least 10 times and 45 minutes ( boiler and Phase 3 were at set temp. ) . So after thinking we have a leaking Phase 3 ............. the pressure stopped rising ?!? It stayed at a steady 14 to 15 psi for 20 minutes .

Here's the strange part and why I think the heater still has a leak that semi-sealed itself after it heated up - whenever we ran the hot tap at a sink , the boiler pressure dropped 5 to 7 psi , then would return to normal after the sink was shut . This was with the PRV valve closed .

We replaced the expansion tank and PRV just to cover the bases and told the homeowner to keep an eye on the pressure . We marked the shutoff valves to the hot and cold of the indirect . The boiler relief was piped to a drain for safety .

Is the boiler pressure drop a normal thing that happens with a tank-in-tank indirect ? Has anyone observed a tank leaking , then stop leaking after heat-up ? Thanks for any help in advance .

Guy Woollard

leaks

Usually a leak ....well, leaks. What I suspect here is an air pocket compressing and causing the fluctuations. The Phase III tank has a suspended , corrugated inner tank, designed to expand and contract with differences in pressure (and thermal expansion)to break off any deposits. The inner tank contracting can cause some drop in the boiler pressure, but 5 lbs seems extreme. Is there any potable expansion tank on the tank? Perhaps thermal expansion is flexing that inner tank to the exteme.

Please let me know.

Guy Woollard
N.E. Regional Sales Mgr
Triangle Tube Corp.

Unknown

Guy

Thanks so much for the reply . So far , no call from the homeowner . I'll put in a call to her tomorrow and see where the pressure is .

We've been using Phase 3 and the Weil Mclain equivalent for years now , and this was the first time I've seen the pressure drop phenomenon . This particular job had a 5 section residential boiler and the 60 gallon HL ( no domestic tank ). I checked my own Peerless and Plus 30 ( with domestic tank ) . The tridicator needle does move very slightly when the hot water tap is opened . My buddy Kenny has a Peerless and 30 gal HL and his did the same - slight movement .

Thanks again Guy , I'll keep you posted .