ST-5 Water Heater Expansion Tank?

Question

A plumber came today to fix something, and he told me that I need to replace the water heater ST-5 expansion tank (I think it is 2 gallon size), since there is no air in there any more. The house was built in 2001. A friend of mine said he can do it for me. Questions:

1) What brand is a good brand to buy? I went to internet, it seems to point to Amtrol THERM-X-TROL ST-5 Expansion Tank, Model Number - ST-5.

2) Any plumbing supply company you recommend? I saw on ebay sell this brand for $32. Also at PlumberSurplus.com, sell it for $49

3) Do I need to buy any other accessories, when this tank is to be replaced? Such as connector or valve? What size? and what brand?

4) Anything else that I need to pay attention to?

Thanks for your help!!

Answer 1

You should be able to just buy a new one and screw the old one off. Amtrol is a good brand so you should be fine with that. Read the instructions for these tanks come preset from the factory. You wont need any other accessories except maybe teflon tape.

Answer 2

where are the last three guys getting there education. everything in the first and second answers was spot on. no one could have explained it better. the TPR or PRV are in no way designed to take the cushion from excess pressure in a closed system. the manufacturers tell you that from the get go. thats why the expansion tank is now required. if the system is not closed thats another story. the last 3 guys need to do there homework or stop posting there comments. your pointing people in the wrong direction and putting personal property and maybe more at risk. instances of water heaters exploding are rare indeed, but not out of the question. how many explosions would you be ok with. Im not ok with any. I install expansion tanks with every new water heater I put into service. Additionally I won t work on a WH that doesn t have a TE tank without installing one before I leave. that way no client can come back and claim that there WH was leaking or damaged and it was my fault because I worked on it last. If there not willing to pay for the expansion tank to be installed where there previously wasn t one in place then I don t do business with them. cudo s for the first 2 guys. keep pointing poeple in the right direction.

Answer 3

this is a simple replacement but if you can drain some of the water out of the tank IE: drain valve then that's your fix by removing water you replace it with air and that's what you need for thermal expansion also I have seen these tanks at Home Depot

Answer 4

should just screw on.. just pick one up at hd or lowes.. did he try to refill the tank with air? it could have a bad valve stem. read the label it should say what the pressure should be these are adjustable and could have been empty when installed