Hot water Tank question

[lawandorder]

Hello All- I have a Weil Mclain indirect hot water tank that is 4 years old. Is there any maintenance or service that should be done to this set-up. It hasnt been touched or looked at since it was installed. I seem to be using more hot water than normal with the oil burner running more than usual. We arent using any appliances more than usual not sure if there is anything that I should be doing as in preventitive maintence etc.. Thanks

 

[Nofossil]

Hello All- I have a Weil Mclain indirect hot water tank that is 4 years old. Is there any maintenance or service that should be done to this set-up. It hasnt been touched or looked at since it was installed. I seem to be using more hot water than normal with the oil burner running more than usual. We arent using any appliances more than usual not sure if there is anything that I should be doing as in preventitive maintence etc.. Thanks

Two things I can think of:

1) If you have hard water, the HX coil can get caked up on the DHW side. I don't know about yours, but the SuperStor uses a stainless steel pipe with thousands of little fins - almost like stainless steel fur. You can detect caking by looking at the temperature difference across the boiler side of the HX coil. It should be large - at least 20 degrees.

2) You can sometimes get thermosiphoning within the DHW lines. This can be detected by feeling the DHW pipe a few feet from the tank when not hot water has been used in a long time.

If you have hard water deposits, I'd suggest draining the tank and putting in 10 or 20 gallons of white vinegar. Let it sit for a couple of days - heat it up if you'd like. Shake the tank as much as you can, then drain and flush.

If you have thermosiphoning, you can install a 'cold trap' or get a little plastic valve that sits in the outlet and requires a little pressure to pop it open. I've seen them in hardware stores sold for this exact purpose.

 

[NHFarmer]

I believe the Weil Mclain tank is actually a tank within a tank. Mine started leaking around the top, the outer tank is steel and the inner tank is SS. Check on the warranty, mine had a lifetime warranty and they replaced it for free.

 

[Gooserider]

It is also possible that you have built up a lot of sediment in the bottom of the tank - It certainly wouldn't do any harm to try doing a flush out / drain on the tank to see...

Also there is a magnesium sacrificial anode rod in most tanks that is intended to protect the rest of the tank by corroding first... There are claims that tanks can be made to last much longer by replacing that rod periodically. 4 years old is a bit early to need to replace that rod, but again it would be a low cost thing to check...

Gooserider

 

[in hot water]

Most of those Weil tanks are a tank in tank design. They typically don't scale up like a coiled HX tank.

How hard is your water? How many gallons per day, month, or year gets run through it? Also the temperature on the boiler side has some effect on hard scale. Hotter the water the more the minerals precip out.

Not sure what you mean by you are using more hot water?

You can do a draindown test. Let the tank shut off, take a 5 gallon bucket and see how much hot water, at what temperature you get. the owners manual, or online spec will tell you what to expect.

then you could see how long it takes to recover with no HW draw.

Or measure the delta t across the supply and return to the boiler to see how much energy is being transfered from the boiler to the domestic.

You could have a thermostat problem, some of those Weils had a cheesey aquastat. IMO.

Or the pump or zone valve supplying the boiler to the tank?

Or the kids are taking a lot longer shower than normal

hr