Plumbing help please

[ChrisCairns]

My son has an old, very old, house. (I think Chuck Leeper worked on it so you know how old it is). :biggrin:

My son had to fix some upstairs piping, old galvanized pipe, so turned off the water to the upstairs. Since that time his newer one year old hot water tank started to drip out of the relief valve. He replaced the valve, and it still leaked, then he thought the thermostat was bad and overheating the water, so he replaced that. Nada. The relief valve still leaks. We started to think that perhaps his turning off of the upstairs water has something to do with it, such as nowhere for the water to expand while it's heating.

Does this make sense? Does water need somewhere to expand? And what's normally done in a newer house for expansion.

Thanks.

 

[John Wilde]

My son has an old, very old, house. (I think Chuck Leeper worked on it so you know how old it is). :biggrin:

My son had to fix some upstairs piping, old galvanized pipe, so turned off the water to the upstairs. Since that time his newer one year old hot water tank started to drip out of the relief valve. He replaced the valve, and it still leaked, then he thought the thermostat was bad and overheating the water, so he replaced that. Nada. The relief valve still leaks. We started to think that perhaps his turning off of the upstairs water has something to do with it, such as nowhere for the water to expand while it's heating.

Does this make sense? Does water need somewhere to expand? And what's normally done in a newer house for expansion.

Thanks.

PM Ted A.

 

[gnxtc2]

BTW, it's not a hot water heater...it's a water heater. Why would want to heat the hot water. :tongue: :tongue: :tongue: :tongue: :tongue:

Billy T.
gnxtc2@aol.com

 

[S2V6RACER]

My son has an old, very old, house. (I think Chuck Leeper worked on it so you know how old it is). :biggrin:

My son had to fix some upstairs piping, old galvanized pipe, so turned off the water to the upstairs. Since that time his newer one year old hot water tank started to drip out of the relief valve. He replaced the valve, and it still leaked, then he thought the thermostat was bad and overheating the water, so he replaced that. Nada. The relief valve still leaks. We started to think that perhaps his turning off of the upstairs water has something to do with it, such as nowhere for the water to expand while it's heating.

Does this make sense? Does water need somewhere to expand? And what's normally done in a newer house for expansion.

Thanks.

It is feasible that if you have a water softener system with a check valve on the inlet side you could have a thermo expansion issue causing the T&P valve to drip. No way it's temp related, you would know. If you open a hot water tap the valve would stop dripping if it was pressure related. If you use the T&P as a drain point (you open it up to drain water) sometimes they don't seat back up again. Try to install a new valve, just because they are new doesn't mean they are good.

High city water pressure??? You can put a guage on the system and check the PSI also...

 

[John Larkin]

It is a temperature/pressure relief valve. 210° or 150 psi opens it, like a radiator cap. I read you can buy a pressure gauge that screws onto the drain valve for <$10 at Home Depot. I'd be buying one.

 

[ChrisCairns]

Thanks guys.

First, Billy T....that was hilarious yet true. (Although if you check my original post I didn't say hot water heater, I said tank. :biggrin: ) But we still both laughed at it.

Second, Ted. No water softener and my son said if he opened a tap the drip would stop. We both assumed it was pressure related. He just told me tonight he'd removed about 14 to 16 feet of the old galvanized pipe so we're also assuming it was THAT amount of pipe which was allowing for thermal expansion of the water. All the pipe would expand just a bit we think. Does that make sense? And now without the extra pipe, nothing to absorb the expansion.

Third, John. He went to buy one after work today. In our small town's small hardware store they didn't have one. But what he did was buy a herd of pvc and he's working on puttitng in a temporary homemade highfalluting "air expansion chamber." ( 5 feet of pvc straight up inside the wall, capped off to catch air inside and connected to a turn on valve thingy.)

Thanks gents for your help.

 

[S2V6RACER]

It is not a bad idea to install a thermo expansion tank. Make sure you get one for potable water the ones for heating systems will rust internally.

 

[ChrisCairns]

It's fixed. He installed what I described....a straight up pipe capped at the end so it holds air.

Hey, I may become a plumber....I suck at car crap. :tongue:

 

[S2V6RACER]

Chris, you still must have a check valve located somewhere between the street (if you have city water) and or well tank. You have a closed system and that isn't typical. Higher pressures should push back through the hot water tank to the cold water toward the pressure tank(if you have a well) or back through the meter toward the city water supply.

The code states you must address thermo expansion when present, the only way to do it to code is with a tank. Your air chamber will work for a while, but it will become waterlogged in a few weeks. They are no longer recognized methods of water hammer arresting and definately not thermo expansion, but it will work(temporarily). A good tank will run you around $40.00.

 

[ChrisCairns]

Chris, you still must have a check valve located somewhere between the street (if you have city water) and or well tank. You have a closed system and that isn't typical. Higher pressures should push back through the hot water tank to the cold water toward the pressure tank(if you have a well) or back through the meter toward the city water supply.

The code states you must address thermo expansion when present, the only way to do it to code is with a tank. Your air chamber will work for a while, but it will become waterlogged in a few weeks. They are no longer recognized methods of water hammer arresting and definately not thermo expansion, but it will work(temporarily). A good tank will run you around $40.00.

Thanks...I appreciate you answering once again. It's nice to hear from a real plumber.

It's city water, and we kicked around the idea that the expansion would go back to the street. At the same time I put the request for info here, we were asking customers who came into the store yesterday about plumbing....yes, small town, we do that. Anyway, one guy who was from the coast (big city) said the cities over there required a one way valve to STOP each house from putting water back into the system. I assume to stop the weidos from putting crap into the system and pushing it back for others to injest. We don't know if our small town requres this type of thing or if his house even has one.

So my still wondering brain, wonders why this 100+ year old house, albeit upgraded water system, was working fine until he took out the 15 or so feet of upstairs water pipes. All we could come up with was that the pipes going upstairs were expanding to accept the higher pressure of the expanding hot water. Hence the air-trapped water pipe.

It is temporary since he's now (today) putting back in the pipes he took out. The question is....will the system return to normal, i.e. not requiring an expansion tank as you suggest, or continue to leak at the tank.

I assume time wll tell, and maybe he'll have to put in the tank thingy if it continues to be a problem.

Thanks again, for replying.