Boiler leaks when shut down

9 yrs old its like anything else depends on maintenance and quality of unit --not safe since if safety doesnt shut down unit much more damage can occur

It would seem a joint has come a bit loose from the heating and cooling cycle. put a drip pan under the leaking area( the drips would evaporate quickly), then next time you shut it down go through all the joints in the area with wrenches to find the loose joint.

Check all the connections, take the cover off after you shut down the power. If the connectors are not leaking, replace it

First shut off power then remove acess cover and carefully move insulation out of the way so you can see around elements.Check to see if leak is coming from around element.If it is determine what type of element you have. Either screw in or bolted in. Both have thick rubber gaskets that can be replaced by draing water heater and removing element then install new gasket and reinstall element.
To drain heater shut off valve on incoming cold water supply line ,make sure electric power is off. Connect drain hose to drain valve and put other end to floor drain or sump basin.You can open faucet on hot side near by to prevent vacumn and drain. If you have screw in type disconnect wires,marking them for reattachment,then use large open end wrench or pipe wrench on hex section of element and turn to left to remove. If you have bolt in element spray bolts with wd-40 or similar and carefully loosen bolts then disconnect wires and remove element.install new gasket and reverse to reinstall. I would recommend that you replace elements at this time if you are sure this was the source of the leak.
If you don't think it's leaking around elements then check fitting on both water lines to water heater to be sure they are not leaking and seeping down thru insulation and leaking out of the bottom of heater. Next check around drain valve for leak and if it's leaking you can try tightening it a little or replace it with 3/4 x2 brass nipple and 3/4 inch female iron pipe boiler drain. Use teflon tape or pipe joint compound on all threaded connections.
After you have eliminated all other sources for leak then it is probably the tank itself. If it is less then six years old the tank should still be covered under warrenty. Most warrenties will give you a new heater but installation will not be covered unless you have extended service coverage.
I hope this helps you some. Thank you

HI sorry its shot, they go every now &then.You can run it like you say temporary BUT the boiler needs low pressure to force heat @10 or 12 p.s.i. This pressure will leak out of the hole and you eventaully loose heat & get noise.If you got a pinhole leak in tank.With the main off.Slow it down with duct tape or a rag if you can and leave water on.

If there is no leak anywhere in the system [pipes & radiators] Check the emergency pressure relief valve. It usually is at the base of the boiler and drains to outside [15mm pipe] where, if the valve leaks, water drips can be seen.. Looks similar to the picture with your query
Renew the valve
You can take it apart and clean it but I've never found that to be successful in the long term

what kind of heater combi? if combi you may be pressurising boiler to high ie over 1 bar boiler may be blowing off through release valve check discharge pipe

If you are losing boiler pressure, it is probably not the expansion tank. Most of the time when these go bad they fill with water and cause a increase in boiler pressure, especially when the boiler is running. If you put a tire gauge on the end of the tank it should read between 10 and 15 psi. If this is the case then the expansion tank is fine. If the tank is fine then you may have a leak somewhere in the system. The perculating that you refer to could also be from the boiler being under filled. Make sure all zones are purged of air and the boiler pressure reads around 12 psi on the gauge. Hope this helps

there ic a low water cut-off on all boilers, also a over pressure switch that can shut down the unit. You should really call a service company out to look at the problem due to the potential of a serius problem with thee unit and see whats is the problem with the unit. Boilers can explode and do allot of damage to a person and property if this happ[ens. GOod Luck

Hi, it appears you have a defected relief valve. you can try one solution. lift the handle on the relief valve and let some water out. sometimes that can flush out materials thats blocking the stem in the valve. if it's still leaking it must be replace.

If this doesn’t work for you please write back. Thanks,