Both boiler and hwh relief valves release

D107

Got a call from my mother in Nassau County that both buckets under her Buderus G115 boiler and the Buderus indirect hwh were full of water. Must have happened many hours prior to her discovery since water under hwh was cold and under boiler was lukewarm. Everything else working ok as far as I know. Why would both blow?

Jamie Hall

Presumably the valves to which you are referring are the pressure and temperature relief valves?

For them both to open more at less at once suggests either a really weird coincidence -- or that for some reason there was a pressure spike which affected both units. Which without more information also seems a bit unlikely.

Can you provide more information on exactly which valves were involved, and any information on the water feed arrangements for the boiler? Any expansion tanks on the system?

D107

Thanks Jamie. Not being on-site but recalling that the buckets were below the output pipe of the relief valves (pressure and tmp/relief valves.) Boiler G115/3 has a Watts WP Relief Valve Model 374 and Extrol Diaphragm exp tank size 30 set at 13lbs in fall 2006 since first installed but not checked since then. Indirect Buderus St-150/2 has a Watts 40XL tmp/pressure valve. When the indirect was first installed they had a 100XL on it but that popped so they put the 40XL in. Indirect has an Amtrol Therm-X Span T-12 expansion tank, set at 75lbs when first installed. This was installed by a solid installer and runs very well. See attached photos of the then-new boiler install and indirect pic from a few years ago.
The last I heard on this--hours later--is that there is currently about an inch of water in the bucket under the indirect.

D107

It just occurred to me: if there was a spike in house water pressure--due to maybe a faulty pressure regulating valve on the main--could that cause this problem?

D107

Latest this morning: no water in boiler bucket; very little in indirect bucket, but some water on blocks upon which indirect sits. It's possible that this water on the blocks could come from --see 2nd photo in other post--the rusted connection at bottom of indirect. fyi whatever water had discharged yesterday was apparently clear not brown. Also, if this is a street water pressure issue I believe that in this area pressure regulating valves are outside the house at curb level under a protective plate, unlike in other places where the valve is inside the house and controlled by the homeowner.

Jamie Hall

It's likely that it was a street water pressure problem. Worth keeping an eye on, though.

D107

Spoke to the water dept, they say their water tower keeps pressure steady between 60-70lb. If the buderus hot water sensor in the indirect malfunctions and the boiler keeps firing to make hot water, that might explain the discharges, yes? and the water on the floor/blocks I guess could be from a connection under temporary pressure(?)