[lexluthor]

We just had a sprinkler system installed yesterday and I just noticed that the HW heater pressure relief valve is dripping hot water occasionally.

I had the boiler tech just come out and he said that I need to have an expansion tank installed on the HW heater and that he's certain that's the issue. He was unable to do it on the spot and suggested I find out why the sprinkler guys didn't do it.

Does that make sense?

Also, we are leaving on vacation tomorrow morning. I turned off the boiler and shut off the water to the boiler. But, I still want to run the sprinklers because we have a newly seeded lawn that will need water.

Will I be safe for the week that way? It's going to be 45-70 degrees out while we are gone.

 

[supers05]

Safe? Yes. Expansion tank needs to be down stream of any back flow preventer or check valve that creates an isolated system. This may mean at least one in the house. With the heater off, it's not really needed.

You can install the expansion tank yourself if you're willing to get your hands dirty. It's not terribly hard, especially with fittings like sharkbite

Cheers!

 

[lexluthor]

No problem while I was away.

Came back and turned on boiler again and later that evening had a funny mothball type smell in house. Called FD and they detected some low levels of CO and thought that the burner was putting out some CO when that kicked in. Does turning the boiler off for a week have anything to do with that?

Boiler tech installed the expansion tank. Confident that will remedy the problem with the overflow water dripping out. Now he's giving the boiler/burner a thorough cleaning.

He also tested the water pressure and said we are at around 85-87 or so and we should look into a plumber installing a pressure reducing valve. Is that something that would be recommended?

 

[how]

Your house water pressure is too high..Most new homes get adjusted to about 49 PSI while older homes with possible old black iron fittings still behind the walls will get up to 70PSI to compensate for the restrictive water flow.
Above that pressure..... tap washers, toilet valves, dishwasher & clothes washing solenoid valves, and especially hot water tanks...will get reduced lifespans.

The house pressure reducing valve should be installed after your house shut and your outside hose take off.
The sprinkler guys would not normally concern themselves with your HWT relief valve unless it was leaking while they were there....and you already have a house water pressure reducing valve that they turned up for that sprinkler system.

 

[supers05]

50-60psi is normal for around here. How is right. Might be hard to get it installed after the outside hose branch though. (in my house it's the last item on the run.)

Cheers!

 

[78Vette]

We just had a sprinkler system installed yesterday and I just noticed that the HW heater pressure relief valve is dripping hot water occasionally.

I had the boiler tech just come out and he said that I need to have an expansion tank installed on the HW heater and that he's certain that's the issue. He was unable to do it on the spot and suggested I find out why the sprinkler guys didn't do it.

Does that make sense?
.

I had the same problem and was told since i have a back-flow preventer
, the water has no place to go when it's heating up, causing the tip. Installing a small expansion tank was needed and done. No problems since.

 

[yuri]

I hate backflow preventers.:vs_mad:

We had HUGE ones in the hospital I worked in and nothing but problems with them and everywhere else. They also contribute to pressure drop in large bldgs.

I would have thought or guessed a pressure spike from when the solenoid valve on the sprinklers closed was causing water hammer and a arrestor was needed. However I don't have hw heat or do many resi boilers anymore. Looks like it was a expansion tank not arrestor to do the trick.:wink2:

 

[how]

I have never seen a residential hot water boiler without an expansion tank.
I have seen systems with blown expansion tanks still operate properly when they had old fashioned upright rads that also operated as expansion tanks when they got enough air in them
but
its a dodge between too much air causing an air lock and too little air causing the pressure relief valve to vent.